Squashed 'third_party/git/' content from commit cb71568594

git-subtree-dir: third_party/git
git-subtree-split: cb715685942260375e1eb8153b0768a376e4ece7

48 files changed, 3105 insertions, 0 deletions

diff --git a/t/perf/.gitignore b/t/perf/.gitignore
new file mode 100644
index 000000000000..982eb8e3a949
--- /dev/null
+++ b/t/perf/.gitignore
@@ -0,0 +1,3 @@
+/build/
+/test-results/
+/trash directory*/
diff --git a/t/perf/Makefile b/t/perf/Makefile
new file mode 100644
index 000000000000..8c47155a7c86
--- /dev/null
+++ b/t/perf/Makefile
@@ -0,0 +1,15 @@
+-include ../../config.mak
+export GIT_TEST_OPTIONS
+
+all: perf
+
+perf: pre-clean
+	./run
+
+pre-clean:
+	rm -rf test-results
+
+clean:
+	rm -rf build "trash directory".* test-results
+
+.PHONY: all perf pre-clean clean
diff --git a/t/perf/README b/t/perf/README
new file mode 100644
index 000000000000..c7b70e2d28ba
--- /dev/null
+++ b/t/perf/README
@@ -0,0 +1,195 @@
+Git performance tests
+=====================
+
+This directory holds performance testing scripts for git tools.  The
+first part of this document describes the various ways in which you
+can run them.
+
+When fixing the tools or adding enhancements, you are strongly
+encouraged to add tests in this directory to cover what you are
+trying to fix or enhance.  The later part of this short document
+describes how your test scripts should be organized.
+
+
+Running Tests
+-------------
+
+The easiest way to run tests is to say "make".  This runs all
+the tests on the current git repository.
+
+    === Running 2 tests in this tree ===
+    [...]
+    Test                                     this tree
+    ---------------------------------------------------------
+    0001.1: rev-list --all                   0.54(0.51+0.02)
+    0001.2: rev-list --all --objects         6.14(5.99+0.11)
+    7810.1: grep worktree, cheap regex       0.16(0.16+0.35)
+    7810.2: grep worktree, expensive regex   7.90(29.75+0.37)
+    7810.3: grep --cached, cheap regex       3.07(3.02+0.25)
+    7810.4: grep --cached, expensive regex   9.39(30.57+0.24)
+
+You can compare multiple repositories and even git revisions with the
+'run' script:
+
+    $ ./run . origin/next /path/to/git-tree p0001-rev-list.sh
+
+where . stands for the current git tree.  The full invocation is
+
+    ./run [<revision|directory>...] [--] [<test-script>...]
+
+A '.' argument is implied if you do not pass any other
+revisions/directories.
+
+You can also manually test this or another git build tree, and then
+call the aggregation script to summarize the results:
+
+    $ ./p0001-rev-list.sh
+    [...]
+    $ ./run /path/to/other/git -- ./p0001-rev-list.sh
+    [...]
+    $ ./aggregate.perl . /path/to/other/git ./p0001-rev-list.sh
+
+aggregate.perl has the same invocation as 'run', it just does not run
+anything beforehand.
+
+You can set the following variables (also in your config.mak):
+
+    GIT_PERF_REPEAT_COUNT
+	Number of times a test should be repeated for best-of-N
+	measurements.  Defaults to 3.
+
+    GIT_PERF_MAKE_OPTS
+	Options to use when automatically building a git tree for
+	performance testing. E.g., -j6 would be useful. Passed
+	directly to make as "make $GIT_PERF_MAKE_OPTS".
+
+    GIT_PERF_MAKE_COMMAND
+	An arbitrary command that'll be run in place of the make
+	command, if set the GIT_PERF_MAKE_OPTS variable is
+	ignored. Useful in cases where source tree changes might
+	require issuing a different make command to different
+	revisions.
+
+	This can be (ab)used to monkeypatch or otherwise change the
+	tree about to be built. Note that the build directory can be
+	re-used for subsequent runs so the make command might get
+	executed multiple times on the same tree, but don't count on
+	any of that, that's an implementation detail that might change
+	in the future.
+
+    GIT_PERF_REPO
+    GIT_PERF_LARGE_REPO
+	Repositories to copy for the performance tests.  The normal
+	repo should be at least git.git size.  The large repo should
+	probably be about linux.git size for optimal results.
+	Both default to the git.git you are running from.
+
+You can also pass the options taken by ordinary git tests; the most
+useful one is:
+
+--root=<directory>::
+	Create "trash" directories used to store all temporary data during
+	testing under <directory>, instead of the t/ directory.
+	Using this option with a RAM-based filesystem (such as tmpfs)
+	can massively speed up the test suite.
+
+
+Naming Tests
+------------
+
+The performance test files are named as:
+
+	pNNNN-commandname-details.sh
+
+where N is a decimal digit.  The same conventions for choosing NNNN as
+for normal tests apply.
+
+
+Writing Tests
+-------------
+
+The perf script starts much like a normal test script, except it
+sources perf-lib.sh:
+
+	#!/bin/sh
+	#
+	# Copyright (c) 2005 Junio C Hamano
+	#
+
+	test_description='xxx performance test'
+	. ./perf-lib.sh
+
+After that you will want to use some of the following:
+
+	test_perf_fresh_repo    # sets up an empty repository
+	test_perf_default_repo  # sets up a "normal" repository
+	test_perf_large_repo    # sets up a "large" repository
+
+	test_perf_default_repo sub  # ditto, in a subdir "sub"
+
+        test_checkout_worktree  # if you need the worktree too
+
+At least one of the first two is required!
+
+You can use test_expect_success as usual. In both test_expect_success
+and in test_perf, running "git" points to the version that is being
+perf-tested. The $MODERN_GIT variable points to the git wrapper for the
+currently checked-out version (i.e., the one that matches the t/perf
+scripts you are running).  This is useful if your setup uses commands
+that only work with newer versions of git than what you might want to
+test (but obviously your new commands must still create a state that can
+be used by the older version of git you are testing).
+
+For actual performance tests, use
+
+	test_perf 'descriptive string' '
+		command1 &&
+		command2
+	'
+
+test_perf spawns a subshell, for lack of better options.  This means
+that
+
+* you _must_ export all variables that you need in the subshell
+
+* you _must_ flag all variables that you want to persist from the
+  subshell with 'test_export':
+
+	test_perf 'descriptive string' '
+		foo=$(git rev-parse HEAD) &&
+		test_export foo
+	'
+
+  The so-exported variables are automatically marked for export in the
+  shell executing the perf test.  For your convenience, test_export is
+  the same as export in the main shell.
+
+  This feature relies on a bit of magic using 'set' and 'source'.
+  While we have tried to make sure that it can cope with embedded
+  whitespace and other special characters, it will not work with
+  multi-line data.
+
+Rather than tracking the performance by run-time as `test_perf` does, you
+may also track output size by using `test_size`. The stdout of the
+function should be a single numeric value, which will be captured and
+shown in the aggregated output. For example:
+
+	test_perf 'time foo' '
+		./foo >foo.out
+	'
+
+	test_size 'output size'
+		wc -c <foo.out
+	'
+
+might produce output like:
+
+	Test                origin           HEAD
+	-------------------------------------------------------------
+	1234.1 time foo     0.37(0.79+0.02)  0.26(0.51+0.02) -29.7%
+	1234.2 output size             4.3M             3.6M -14.7%
+
+The item being measured (and its units) is up to the test; the context
+and the test title should make it clear to the user whether bigger or
+smaller numbers are better. Unlike test_perf, the test code will only be
+run once, since output sizes tend to be more deterministic than timings.
diff --git a/t/perf/aggregate.perl b/t/perf/aggregate.perl
new file mode 100755
index 000000000000..66554d216122
--- /dev/null
+++ b/t/perf/aggregate.perl
@@ -0,0 +1,357 @@
+#!/usr/bin/perl
+
+use lib '../../perl/build/lib';
+use strict;
+use warnings;
+use Getopt::Long;
+use Git;
+use Cwd qw(realpath);
+
+sub get_times {
+	my $name = shift;
+	open my $fh, "<", $name or return undef;
+	my $line = <$fh>;
+	return undef if not defined $line;
+	close $fh or die "cannot close $name: $!";
+	# times
+	if ($line =~ /^(?:(\d+):)?(\d+):(\d+(?:\.\d+)?) (\d+(?:\.\d+)?) (\d+(?:\.\d+)?)$/) {
+		my $rt = ((defined $1 ? $1 : 0.0)*60+$2)*60+$3;
+		return ($rt, $4, $5);
+	# size
+	} elsif ($line =~ /^\d+$/) {
+		return $&;
+	} else {
+		die "bad input line: $line";
+	}
+}
+
+sub relative_change {
+	my ($r, $firstr) = @_;
+	if ($firstr > 0) {
+		return sprintf "%+.1f%%", 100.0*($r-$firstr)/$firstr;
+	} elsif ($r == 0) {
+		return "=";
+	} else {
+		return "+inf";
+	}
+}
+
+sub format_times {
+	my ($r, $u, $s, $firstr) = @_;
+	# no value means we did not finish the test
+	if (!defined $r) {
+		return "<missing>";
+	}
+	# a single value means we have a size, not times
+	if (!defined $u) {
+		return format_size($r, $firstr);
+	}
+	# otherwise, we have real/user/system times
+	my $out = sprintf "%.2f(%.2f+%.2f)", $r, $u, $s;
+	$out .= ' ' . relative_change($r, $firstr) if defined $firstr;
+	return $out;
+}
+
+sub usage {
+	print <<EOT;
+./aggregate.perl [options] [--] [<dir_or_rev>...] [--] [<test_script>...] >
+
+  Options:
+    --codespeed          * Format output for Codespeed
+    --reponame    <str>  * Send given reponame to codespeed
+    --sort-by     <str>  * Sort output (only "regression" criteria is supported)
+    --subsection  <str>  * Use results from given subsection
+
+EOT
+	exit(1);
+}
+
+sub human_size {
+	my $n = shift;
+	my @units = ('', qw(K M G));
+	while ($n > 900 && @units > 1) {
+		$n /= 1000;
+		shift @units;
+	}
+	return $n unless length $units[0];
+	return sprintf '%.1f%s', $n, $units[0];
+}
+
+sub format_size {
+	my ($size, $first) = @_;
+	# match the width of a time: 0.00(0.00+0.00)
+	my $out = sprintf '%15s', human_size($size);
+	$out .= ' ' . relative_change($size, $first) if defined $first;
+	return $out;
+}
+
+my (@dirs, %dirnames, %dirabbrevs, %prefixes, @tests,
+    $codespeed, $sortby, $subsection, $reponame);
+
+Getopt::Long::Configure qw/ require_order /;
+
+my $rc = GetOptions("codespeed"     => \$codespeed,
+		    "reponame=s"    => \$reponame,
+		    "sort-by=s"     => \$sortby,
+		    "subsection=s"  => \$subsection);
+usage() unless $rc;
+
+while (scalar @ARGV) {
+	my $arg = $ARGV[0];
+	my $dir;
+	my $prefix = '';
+	last if -f $arg or $arg eq "--";
+	if (! -d $arg) {
+		my $rev = Git::command_oneline(qw(rev-parse --verify), $arg);
+		$dir = "build/".$rev;
+	} elsif ($arg eq '.') {
+		$dir = '.';
+	} else {
+		$dir = realpath($arg);
+		$dirnames{$dir} = $dir;
+		$prefix .= 'bindir';
+	}
+	push @dirs, $dir;
+	$dirnames{$dir} ||= $arg;
+	$prefix .= $dir;
+	$prefix =~ tr/^a-zA-Z0-9/_/c;
+	$prefixes{$dir} = $prefix . '.';
+	shift @ARGV;
+}
+
+if (not @dirs) {
+	@dirs = ('.');
+}
+$dirnames{'.'} = $dirabbrevs{'.'} = "this tree";
+$prefixes{'.'} = '';
+
+shift @ARGV if scalar @ARGV and $ARGV[0] eq "--";
+
+@tests = @ARGV;
+if (not @tests) {
+	@tests = glob "p????-*.sh";
+}
+
+my $resultsdir = "test-results";
+
+if (! $subsection and
+    exists $ENV{GIT_PERF_SUBSECTION} and
+    $ENV{GIT_PERF_SUBSECTION} ne "") {
+	$subsection = $ENV{GIT_PERF_SUBSECTION};
+}
+
+if ($subsection) {
+	$resultsdir .= "/" . $subsection;
+}
+
+my @subtests;
+my %shorttests;
+for my $t (@tests) {
+	$t =~ s{(?:.*/)?(p(\d+)-[^/]+)\.sh$}{$1} or die "bad test name: $t";
+	my $n = $2;
+	my $fname = "$resultsdir/$t.subtests";
+	open my $fp, "<", $fname or die "cannot open $fname: $!";
+	for (<$fp>) {
+		chomp;
+		/^(\d+)$/ or die "malformed subtest line: $_";
+		push @subtests, "$t.$1";
+		$shorttests{"$t.$1"} = "$n.$1";
+	}
+	close $fp or die "cannot close $fname: $!";
+}
+
+sub read_descr {
+	my $name = shift;
+	open my $fh, "<", $name or return "<error reading description>";
+	binmode $fh, ":utf8" or die "PANIC on binmode: $!";
+	my $line = <$fh>;
+	close $fh or die "cannot close $name";
+	chomp $line;
+	return $line;
+}
+
+sub have_duplicate {
+	my %seen;
+	for (@_) {
+		return 1 if exists $seen{$_};
+		$seen{$_} = 1;
+	}
+	return 0;
+}
+sub have_slash {
+	for (@_) {
+		return 1 if m{/};
+	}
+	return 0;
+}
+
+sub display_dir {
+	my ($d) = @_;
+	return exists $dirabbrevs{$d} ? $dirabbrevs{$d} : $dirnames{$d};
+}
+
+sub print_default_results {
+	my %descrs;
+	my $descrlen = 4; # "Test"
+	for my $t (@subtests) {
+		$descrs{$t} = $shorttests{$t}.": ".read_descr("$resultsdir/$t.descr");
+		$descrlen = length $descrs{$t} if length $descrs{$t}>$descrlen;
+	}
+
+	my %newdirabbrevs = %dirabbrevs;
+	while (!have_duplicate(values %newdirabbrevs)) {
+		%dirabbrevs = %newdirabbrevs;
+		last if !have_slash(values %dirabbrevs);
+		%newdirabbrevs = %dirabbrevs;
+		for (values %newdirabbrevs) {
+			s{^[^/]*/}{};
+		}
+	}
+
+	my %times;
+	my @colwidth = ((0)x@dirs);
+	for my $i (0..$#dirs) {
+		my $w = length display_dir($dirs[$i]);
+		$colwidth[$i] = $w if $w > $colwidth[$i];
+	}
+	for my $t (@subtests) {
+		my $firstr;
+		for my $i (0..$#dirs) {
+			my $d = $dirs[$i];
+			my $base = "$resultsdir/$prefixes{$d}$t";
+			$times{$prefixes{$d}.$t} = [];
+			foreach my $type (qw(times size)) {
+				if (-e "$base.$type") {
+					$times{$prefixes{$d}.$t} = [get_times("$base.$type")];
+					last;
+				}
+			}
+			my ($r,$u,$s) = @{$times{$prefixes{$d}.$t}};
+			my $w = length format_times($r,$u,$s,$firstr);
+			$colwidth[$i] = $w if $w > $colwidth[$i];
+			$firstr = $r unless defined $firstr;
+		}
+	}
+	my $totalwidth = 3*@dirs+$descrlen;
+	$totalwidth += $_ for (@colwidth);
+
+	printf "%-${descrlen}s", "Test";
+	for my $i (0..$#dirs) {
+		printf "   %-$colwidth[$i]s", display_dir($dirs[$i]);
+	}
+	print "\n";
+	print "-"x$totalwidth, "\n";
+	for my $t (@subtests) {
+		printf "%-${descrlen}s", $descrs{$t};
+		my $firstr;
+		for my $i (0..$#dirs) {
+			my $d = $dirs[$i];
+			my ($r,$u,$s) = @{$times{$prefixes{$d}.$t}};
+			printf "   %-$colwidth[$i]s", format_times($r,$u,$s,$firstr);
+			$firstr = $r unless defined $firstr;
+		}
+		print "\n";
+	}
+}
+
+sub print_sorted_results {
+	my ($sortby) = @_;
+
+	if ($sortby ne "regression") {
+		print "Only 'regression' is supported as '--sort-by' argument\n";
+		usage();
+	}
+
+	my @evolutions;
+	for my $t (@subtests) {
+		my ($prevr, $prevu, $prevs, $prevrev);
+		for my $i (0..$#dirs) {
+			my $d = $dirs[$i];
+			my ($r, $u, $s) = get_times("$resultsdir/$prefixes{$d}$t.times");
+			if ($i > 0 and defined $r and defined $prevr and $prevr > 0) {
+				my $percent = 100.0 * ($r - $prevr) / $prevr;
+				push @evolutions, { "percent"  => $percent,
+						    "test"     => $t,
+						    "prevrev"  => $prevrev,
+						    "rev"      => $d,
+						    "prevr"    => $prevr,
+						    "r"        => $r,
+						    "prevu"    => $prevu,
+						    "u"        => $u,
+						    "prevs"    => $prevs,
+						    "s"        => $s};
+			}
+			($prevr, $prevu, $prevs, $prevrev) = ($r, $u, $s, $d);
+		}
+	}
+
+	my @sorted_evolutions = sort { $b->{percent} <=> $a->{percent} } @evolutions;
+
+	for my $e (@sorted_evolutions) {
+		printf "%+.1f%%", $e->{percent};
+		print " " . $e->{test};
+		print " " . format_times($e->{prevr}, $e->{prevu}, $e->{prevs});
+		print " " . format_times($e->{r}, $e->{u}, $e->{s});
+		print " " . display_dir($e->{prevrev});
+		print " " . display_dir($e->{rev});
+		print "\n";
+	}
+}
+
+sub print_codespeed_results {
+	my ($subsection) = @_;
+
+	my $project = "Git";
+
+	my $executable = `uname -s -m`;
+	chomp $executable;
+
+	if ($subsection) {
+		$executable .= ", " . $subsection;
+	}
+
+	my $environment;
+	if ($reponame) {
+		$environment = $reponame;
+	} elsif (exists $ENV{GIT_PERF_REPO_NAME} and $ENV{GIT_PERF_REPO_NAME} ne "") {
+		$environment = $ENV{GIT_PERF_REPO_NAME};
+	} else {
+		$environment = `uname -r`;
+		chomp $environment;
+	}
+
+	my @data;
+
+	for my $t (@subtests) {
+		for my $d (@dirs) {
+			my $commitid = $prefixes{$d};
+			$commitid =~ s/^build_//;
+			$commitid =~ s/\.$//;
+			my ($result_value, $u, $s) = get_times("$resultsdir/$prefixes{$d}$t.times");
+
+			my %vals = (
+				"commitid" => $commitid,
+				"project" => $project,
+				"branch" => $dirnames{$d},
+				"executable" => $executable,
+				"benchmark" => $shorttests{$t} . " " . read_descr("$resultsdir/$t.descr"),
+				"environment" => $environment,
+				"result_value" => $result_value,
+			    );
+			push @data, \%vals;
+		}
+	}
+
+	require JSON;
+	print JSON::to_json(\@data, {utf8 => 1, pretty => 1, canonical => 1}), "\n";
+}
+
+binmode STDOUT, ":utf8" or die "PANIC on binmode: $!";
+
+if ($codespeed) {
+	print_codespeed_results($subsection);
+} elsif (defined $sortby) {
+	print_sorted_results($sortby);
+} else {
+	print_default_results();
+}
diff --git a/t/perf/bisect_regression b/t/perf/bisect_regression
new file mode 100755
index 000000000000..a94d9955d012
--- /dev/null
+++ b/t/perf/bisect_regression
@@ -0,0 +1,73 @@
+#!/bin/sh
+
+# Read a line coming from `./aggregate.perl --sort-by regression ...`
+# and automatically bisect to find the commit responsible for the
+# performance regression.
+#
+# Lines from `./aggregate.perl --sort-by regression ...` look like:
+#
+# +100.0% p7821-grep-engines-fixed.1 0.04(0.10+0.03) 0.08(0.11+0.08) v2.14.3 v2.15.1
+# +33.3% p7820-grep-engines.1 0.03(0.08+0.02) 0.04(0.08+0.02) v2.14.3 v2.15.1
+#
+
+die () {
+	echo >&2 "error: $*"
+	exit 1
+}
+
+while [ $# -gt 0 ]; do
+	arg="$1"
+	case "$arg" in
+	--help)
+		echo "usage: $0 [--config file] [--subsection subsection]"
+		exit 0
+		;;
+	--config)
+		shift
+		GIT_PERF_CONFIG_FILE=$(cd "$(dirname "$1")"; pwd)/$(basename "$1")
+		export GIT_PERF_CONFIG_FILE
+		shift ;;
+	--subsection)
+		shift
+		GIT_PERF_SUBSECTION="$1"
+		export GIT_PERF_SUBSECTION
+		shift ;;
+	--*)
+		die "unrecognised option: '$arg'" ;;
+	*)
+		die "unknown argument '$arg'"
+		;;
+	esac
+done
+
+read -r regression subtest oldtime newtime oldrev newrev
+
+test_script=$(echo "$subtest" | sed -e 's/\(.*\)\.[0-9]*$/\1.sh/')
+test_number=$(echo "$subtest" | sed -e 's/.*\.\([0-9]*\)$/\1/')
+
+# oldtime and newtime are decimal number, not integers
+
+oldtime=$(echo "$oldtime" | sed -e 's/^\([0-9]\+\.[0-9]\+\).*$/\1/')
+newtime=$(echo "$newtime" | sed -e 's/^\([0-9]\+\.[0-9]\+\).*$/\1/')
+
+test $(echo "$newtime" "$oldtime" | awk '{ print ($1 > $2) }') = 1 ||
+	die "New time '$newtime' shoud be greater than old time '$oldtime'"
+
+tmpdir=$(mktemp -d -t bisect_regression_XXXXXX) || die "Failed to create temp directory"
+echo "$oldtime" >"$tmpdir/oldtime" || die "Failed to write to '$tmpdir/oldtime'"
+echo "$newtime" >"$tmpdir/newtime" || die "Failed to write to '$tmpdir/newtime'"
+
+# Bisecting must be performed from the top level directory (even with --no-checkout)
+(
+	toplevel_dir=$(git rev-parse --show-toplevel) || die "Failed to find top level directory"
+	cd "$toplevel_dir" || die "Failed to cd into top level directory '$toplevel_dir'"
+
+	git bisect start --no-checkout "$newrev" "$oldrev" || die "Failed to start bisecting"
+
+	git bisect run t/perf/bisect_run_script "$test_script" "$test_number" "$tmpdir"
+	res="$?"
+
+	git bisect reset
+
+	exit "$res"
+)
diff --git a/t/perf/bisect_run_script b/t/perf/bisect_run_script
new file mode 100755
index 000000000000..3ebaf1552148
--- /dev/null
+++ b/t/perf/bisect_run_script
@@ -0,0 +1,53 @@
+#!/bin/sh
+
+script="$1"
+test_number="$2"
+info_dir="$3"
+
+# This aborts the bisection immediately
+die () {
+	echo >&2 "error: $*"
+	exit 255
+}
+
+bisect_head=$(git rev-parse --verify BISECT_HEAD) || die "Failed to find BISECT_HEAD ref"
+
+script_number=$(echo "$script" | sed -e "s/^p\([0-9]*\).*\$/\1/") || die "Failed to get script number for '$script'"
+
+oldtime=$(cat "$info_dir/oldtime") || die "Failed to access '$info_dir/oldtime'"
+newtime=$(cat "$info_dir/newtime") || die "Failed to access '$info_dir/newtime'"
+
+cd t/perf || die "Failed to cd into 't/perf'"
+
+result_file="$info_dir/perf_${script_number}_${bisect_head}_results.txt"
+
+GIT_PERF_DIRS_OR_REVS="$bisect_head"
+export GIT_PERF_DIRS_OR_REVS
+
+# Don't use codespeed
+GIT_PERF_CODESPEED_OUTPUT=
+GIT_PERF_SEND_TO_CODESPEED=
+export GIT_PERF_CODESPEED_OUTPUT
+export GIT_PERF_SEND_TO_CODESPEED
+
+./run "$script" >"$result_file" 2>&1 || die "Failed to run perf test '$script'"
+
+rtime=$(sed -n "s/^$script_number\.$test_number:.*\([0-9]\+\.[0-9]\+\)(.*).*\$/\1/p" "$result_file")
+
+echo "newtime: $newtime"
+echo "rtime: $rtime"
+echo "oldtime: $oldtime"
+
+# Compare ($newtime - $rtime) with ($rtime - $oldtime)
+# Times are decimal number, not integers
+
+if test $(echo "$newtime" "$rtime" "$oldtime" | awk '{ print ($1 - $2 > $2 - $3) }') = 1
+then
+	# Current commit is considered "good/old"
+	echo "$rtime" >"$info_dir/oldtime"
+	exit 0
+else
+	# Current commit is considered "bad/new"
+	echo "$rtime" >"$info_dir/newtime"
+	exit 1
+fi
diff --git a/t/perf/lib-pack.sh b/t/perf/lib-pack.sh
new file mode 100644
index 000000000000..d3865db286fc
--- /dev/null
+++ b/t/perf/lib-pack.sh
@@ -0,0 +1,25 @@
+# Helpers for dealing with large numbers of packs.
+
+# create $1 nonsense packs, each with a single blob
+create_packs () {
+	perl -le '
+		my ($n) = @ARGV;
+		for (1..$n) {
+			print "blob";
+			print "data <<EOF";
+			print "$_";
+			print "EOF";
+			print "checkpoint"
+		}
+	' "$@" |
+	git fast-import
+}
+
+# create a large number of packs, disabling any gc which might
+# cause us to repack them
+setup_many_packs () {
+	git config gc.auto 0 &&
+	git config gc.autopacklimit 0 &&
+	git config fastimport.unpacklimit 0 &&
+	create_packs 500
+}
diff --git a/t/perf/min_time.perl b/t/perf/min_time.perl
new file mode 100755
index 000000000000..c1a2717e0772
--- /dev/null
+++ b/t/perf/min_time.perl
@@ -0,0 +1,21 @@
+#!/usr/bin/perl
+
+my $minrt = 1e100;
+my $min;
+
+while (<>) {
+	# [h:]m:s.xx U.xx S.xx
+	/^(?:(\d+):)?(\d+):(\d+(?:\.\d+)?) (\d+(?:\.\d+)?) (\d+(?:\.\d+)?)$/
+		or die "bad input line: $_";
+	my $rt = ((defined $1 ? $1 : 0.0)*60+$2)*60+$3;
+	if ($rt < $minrt) {
+		$min = $_;
+		$minrt = $rt;
+	}
+}
+
+if (!defined $min) {
+	die "no input found";
+}
+
+print $min;
diff --git a/t/perf/p0000-perf-lib-sanity.sh b/t/perf/p0000-perf-lib-sanity.sh
new file mode 100755
index 000000000000..002c21e52a67
--- /dev/null
+++ b/t/perf/p0000-perf-lib-sanity.sh
@@ -0,0 +1,57 @@
+#!/bin/sh
+
+test_description='Tests whether perf-lib facilities work'
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_perf 'test_perf_default_repo works' '
+	foo=$(git rev-parse HEAD) &&
+	test_export foo
+'
+
+test_checkout_worktree
+
+test_perf 'test_checkout_worktree works' '
+	wt=$(find . | wc -l) &&
+	idx=$(git ls-files | wc -l) &&
+	test $wt -gt $idx
+'
+
+baz=baz
+test_export baz
+
+test_expect_success 'test_export works' '
+	echo "$foo" &&
+	test "$foo" = "$(git rev-parse HEAD)" &&
+	echo "$baz" &&
+	test "$baz" = baz
+'
+
+test_perf 'export a weird var' '
+	bar="weird # variable" &&
+	test_export bar
+'
+
+test_perf 'éḿíẗ ńöń-ÁŚĆÍÍ ćḧáŕáćẗéŕś' 'true'
+
+test_expect_success 'test_export works with weird vars' '
+	echo "$bar" &&
+	test "$bar" = "weird # variable"
+'
+
+test_perf 'important variables available in subshells' '
+	test -n "$HOME" &&
+	test -n "$TEST_DIRECTORY" &&
+	test -n "$TRASH_DIRECTORY" &&
+	test -n "$GIT_BUILD_DIR"
+'
+
+test_perf 'test-lib-functions correctly loaded in subshells' '
+	: >a &&
+	test_path_is_file a &&
+	: >b &&
+	test_cmp a b
+'
+
+test_done
diff --git a/t/perf/p0001-rev-list.sh b/t/perf/p0001-rev-list.sh
new file mode 100755
index 000000000000..3042a85666ce
--- /dev/null
+++ b/t/perf/p0001-rev-list.sh
@@ -0,0 +1,48 @@
+#!/bin/sh
+
+test_description="Tests history walking performance"
+
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_perf 'rev-list --all' '
+	git rev-list --all >/dev/null
+'
+
+test_perf 'rev-list --all --objects' '
+	git rev-list --all --objects >/dev/null
+'
+
+test_perf 'rev-list --parents' '
+	git rev-list --parents HEAD >/dev/null
+'
+
+test_expect_success 'create dummy file' '
+	echo unlikely-to-already-be-there >dummy &&
+	git add dummy &&
+	git commit -m dummy
+'
+
+test_perf 'rev-list -- dummy' '
+	git rev-list HEAD -- dummy
+'
+
+test_perf 'rev-list --parents -- dummy' '
+	git rev-list --parents HEAD -- dummy
+'
+
+test_expect_success 'create new unreferenced commit' '
+	commit=$(git commit-tree HEAD^{tree} -p HEAD) &&
+	test_export commit
+'
+
+test_perf 'rev-list $commit --not --all' '
+	git rev-list $commit --not --all >/dev/null
+'
+
+test_perf 'rev-list --objects $commit --not --all' '
+	git rev-list --objects $commit --not --all >/dev/null
+'
+
+test_done
diff --git a/t/perf/p0002-read-cache.sh b/t/perf/p0002-read-cache.sh
new file mode 100755
index 000000000000..cdd105a59452
--- /dev/null
+++ b/t/perf/p0002-read-cache.sh
@@ -0,0 +1,14 @@
+#!/bin/sh
+
+test_description="Tests performance of reading the index"
+
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+count=1000
+test_perf "read_cache/discard_cache $count times" "
+	test-tool read-cache $count
+"
+
+test_done
diff --git a/t/perf/p0003-delta-base-cache.sh b/t/perf/p0003-delta-base-cache.sh
new file mode 100755
index 000000000000..62369eaaf0d9
--- /dev/null
+++ b/t/perf/p0003-delta-base-cache.sh
@@ -0,0 +1,31 @@
+#!/bin/sh
+
+test_description='Test operations that emphasize the delta base cache.
+
+We look at both "log --raw", which should put only trees into the delta cache,
+and "log -Sfoo --raw", which should look at both trees and blobs.
+
+Any effects will be emphasized if the test repository is fully packed (loose
+objects obviously do not use the delta base cache at all). It is also
+emphasized if the pack has long delta chains (e.g., as produced by "gc
+--aggressive"), though cache is still quite noticeable even with the default
+depth of 50.
+
+The setting of core.deltaBaseCacheLimit in the source repository is also
+relevant (depending on the size of your test repo), so be sure it is consistent
+between runs.
+'
+. ./perf-lib.sh
+
+test_perf_large_repo
+
+# puts mostly trees into the delta base cache
+test_perf 'log --raw' '
+	git log --raw >/dev/null
+'
+
+test_perf 'log -S' '
+	git log --raw -Sfoo >/dev/null
+'
+
+test_done
diff --git a/t/perf/p0004-lazy-init-name-hash.sh b/t/perf/p0004-lazy-init-name-hash.sh
new file mode 100755
index 000000000000..1afc08fe7f19
--- /dev/null
+++ b/t/perf/p0004-lazy-init-name-hash.sh
@@ -0,0 +1,56 @@
+#!/bin/sh
+
+test_description='Tests multi-threaded lazy_init_name_hash'
+. ./perf-lib.sh
+
+test_perf_large_repo
+test_checkout_worktree
+
+test_expect_success 'verify both methods build the same hashmaps' '
+	test-tool lazy-init-name-hash --dump --single >out.single &&
+	if test-tool lazy-init-name-hash --dump --multi >out.multi
+	then
+		test_set_prereq REPO_BIG_ENOUGH_FOR_MULTI &&
+		sort <out.single >sorted.single &&
+		sort <out.multi >sorted.multi &&
+		test_cmp sorted.single sorted.multi
+	fi
+'
+
+test_expect_success 'calibrate' '
+	entries=$(wc -l <out.single) &&
+
+	case $entries in
+	?) count=1000000 ;;
+	??) count=100000 ;;
+	???) count=10000 ;;
+	????) count=1000 ;;
+	?????) count=100 ;;
+	??????) count=10 ;;
+	*) count=1 ;;
+	esac &&
+	export count &&
+
+	case $entries in
+	1) entries_desc="1 entry" ;;
+	*) entries_desc="$entries entries" ;;
+	esac &&
+
+	case $count in
+	1) count_desc="1 round" ;;
+	*) count_desc="$count rounds" ;;
+	esac &&
+
+	desc="$entries_desc, $count_desc" &&
+	export desc
+'
+
+test_perf "single-threaded, $desc" "
+	test-tool lazy-init-name-hash --single --count=$count
+"
+
+test_perf REPO_BIG_ENOUGH_FOR_MULTI "multi-threaded, $desc" "
+	test-tool lazy-init-name-hash --multi --count=$count
+"
+
+test_done
diff --git a/t/perf/p0005-status.sh b/t/perf/p0005-status.sh
new file mode 100755
index 000000000000..0b0aa9858f5d
--- /dev/null
+++ b/t/perf/p0005-status.sh
@@ -0,0 +1,49 @@
+#!/bin/sh
+#
+# This test measures the performance of various read-tree
+# and status operations.  It is primarily interested in
+# the algorithmic costs of index operations and recursive
+# tree traversal -- and NOT disk I/O on thousands of files.
+
+test_description="Tests performance of read-tree"
+
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+# If the test repo was generated by ./repos/many-files.sh
+# then we know something about the data shape and branches,
+# so we can isolate testing to the ballast-related commits
+# and setup sparse-checkout so we don't have to populate
+# the ballast files and directories.
+#
+# Otherwise, we make some general assumptions about the
+# repo and consider the entire history of the current
+# branch to be the ballast.
+
+test_expect_success "setup repo" '
+	if git rev-parse --verify refs/heads/p0006-ballast^{commit}
+	then
+		echo Assuming synthetic repo from many-files.sh
+		git branch br_base            master
+		git branch br_ballast         p0006-ballast
+		git config --local core.sparsecheckout 1
+		cat >.git/info/sparse-checkout <<-EOF
+		/*
+		!ballast/*
+		EOF
+	else
+		echo Assuming non-synthetic repo...
+		git branch br_base            $(git rev-list HEAD | tail -n 1)
+		git branch br_ballast         HEAD
+	fi &&
+	git checkout -q br_ballast &&
+	nr_files=$(git ls-files | wc -l)
+'
+
+test_perf "read-tree status br_ballast ($nr_files)" '
+	git read-tree HEAD &&
+	git status
+'
+
+test_done
diff --git a/t/perf/p0006-read-tree-checkout.sh b/t/perf/p0006-read-tree-checkout.sh
new file mode 100755
index 000000000000..78cc23fe2f32
--- /dev/null
+++ b/t/perf/p0006-read-tree-checkout.sh
@@ -0,0 +1,67 @@
+#!/bin/sh
+#
+# This test measures the performance of various read-tree
+# and checkout operations.  It is primarily interested in
+# the algorithmic costs of index operations and recursive
+# tree traversal -- and NOT disk I/O on thousands of files.
+
+test_description="Tests performance of read-tree"
+
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+# If the test repo was generated by ./repos/many-files.sh
+# then we know something about the data shape and branches,
+# so we can isolate testing to the ballast-related commits
+# and setup sparse-checkout so we don't have to populate
+# the ballast files and directories.
+#
+# Otherwise, we make some general assumptions about the
+# repo and consider the entire history of the current
+# branch to be the ballast.
+
+test_expect_success "setup repo" '
+	if git rev-parse --verify refs/heads/p0006-ballast^{commit}
+	then
+		echo Assuming synthetic repo from many-files.sh
+		git branch br_base            master
+		git branch br_ballast         p0006-ballast^
+		git branch br_ballast_alias   p0006-ballast^
+		git branch br_ballast_plus_1  p0006-ballast
+		git config --local core.sparsecheckout 1
+		cat >.git/info/sparse-checkout <<-EOF
+		/*
+		!ballast/*
+		EOF
+	else
+		echo Assuming non-synthetic repo...
+		git branch br_base            $(git rev-list HEAD | tail -n 1)
+		git branch br_ballast         HEAD^ || error "no ancestor commit from current head"
+		git branch br_ballast_alias   HEAD^
+		git branch br_ballast_plus_1  HEAD
+	fi &&
+	git checkout -q br_ballast &&
+	nr_files=$(git ls-files | wc -l)
+'
+
+test_perf "read-tree br_base br_ballast ($nr_files)" '
+	git read-tree -m br_base br_ballast -n
+'
+
+test_perf "switch between br_base br_ballast ($nr_files)" '
+	git checkout -q br_base &&
+	git checkout -q br_ballast
+'
+
+test_perf "switch between br_ballast br_ballast_plus_1 ($nr_files)" '
+	git checkout -q br_ballast_plus_1 &&
+	git checkout -q br_ballast
+'
+
+test_perf "switch between aliases ($nr_files)" '
+	git checkout -q br_ballast_alias &&
+	git checkout -q br_ballast
+'
+
+test_done
diff --git a/t/perf/p0007-write-cache.sh b/t/perf/p0007-write-cache.sh
new file mode 100755
index 000000000000..09595264f09f
--- /dev/null
+++ b/t/perf/p0007-write-cache.sh
@@ -0,0 +1,29 @@
+#!/bin/sh
+
+test_description="Tests performance of writing the index"
+
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_expect_success "setup repo" '
+	if git rev-parse --verify refs/heads/p0006-ballast^{commit}
+	then
+		echo Assuming synthetic repo from many-files.sh
+		git config --local core.sparsecheckout 1
+		cat >.git/info/sparse-checkout <<-EOF
+		/*
+		!ballast/*
+		EOF
+	else
+		echo Assuming non-synthetic repo...
+	fi &&
+	nr_files=$(git ls-files | wc -l)
+'
+
+count=3
+test_perf "write_locked_index $count times ($nr_files files)" "
+	test-tool write-cache $count
+"
+
+test_done
diff --git a/t/perf/p0071-sort.sh b/t/perf/p0071-sort.sh
new file mode 100755
index 000000000000..6e924f5fa3f9
--- /dev/null
+++ b/t/perf/p0071-sort.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+
+test_description='Basic sort performance tests'
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_expect_success 'setup' '
+	git ls-files --stage "*.[ch]" "*.sh" |
+	cut -f2 -d" " |
+	git cat-file --batch >unsorted
+'
+
+test_perf 'sort(1)' '
+	sort <unsorted >expect
+'
+
+test_perf 'string_list_sort()' '
+	test-tool string-list sort <unsorted >actual
+'
+
+test_expect_success 'string_list_sort() sorts like sort(1)' '
+	test_cmp_bin expect actual
+'
+
+test_done
diff --git a/t/perf/p0100-globbing.sh b/t/perf/p0100-globbing.sh
new file mode 100755
index 000000000000..dd18a9ce2b11
--- /dev/null
+++ b/t/perf/p0100-globbing.sh
@@ -0,0 +1,43 @@
+#!/bin/sh
+
+test_description="Tests pathological globbing performance
+
+Shows how Git's globbing performance performs when given the sort of
+pathological patterns described in at https://research.swtch.com/glob
+"
+
+. ./perf-lib.sh
+
+test_globs_big='10 25 50 75 100'
+test_globs_small='1 2 3 4 5 6'
+
+test_perf_fresh_repo
+
+test_expect_success 'setup' '
+	for i in $(test_seq 1 100)
+	do
+		printf "a" >>refname &&
+		for j in $(test_seq 1 $i)
+		do
+			printf "a*" >>refglob.$i
+		done &&
+		echo b >>refglob.$i
+	done &&
+	test_commit test $(cat refname).t "" $(cat refname).t
+'
+
+for i in $test_globs_small
+do
+	test_perf "refglob((a*)^nb) against tag (a^100).t; n = $i" '
+		git for-each-ref "refs/tags/$(cat refglob.'$i')b"
+	'
+done
+
+for i in $test_globs_small
+do
+	test_perf "fileglob((a*)^nb) against file (a^100).t; n = $i" '
+		git ls-files "$(cat refglob.'$i')b"
+	'
+done
+
+test_done
diff --git a/t/perf/p1450-fsck.sh b/t/perf/p1450-fsck.sh
new file mode 100755
index 000000000000..ae1b84198bbc
--- /dev/null
+++ b/t/perf/p1450-fsck.sh
@@ -0,0 +1,13 @@
+#!/bin/sh
+
+test_description='Test fsck performance'
+
+. ./perf-lib.sh
+
+test_perf_large_repo
+
+test_perf 'fsck' '
+	git fsck
+'
+
+test_done
diff --git a/t/perf/p1451-fsck-skip-list.sh b/t/perf/p1451-fsck-skip-list.sh
new file mode 100755
index 000000000000..c2b97d2487bb
--- /dev/null
+++ b/t/perf/p1451-fsck-skip-list.sh
@@ -0,0 +1,40 @@
+#!/bin/sh
+
+test_description='Test fsck skipList performance'
+
+. ./perf-lib.sh
+
+test_perf_fresh_repo
+
+n=1000000
+
+test_expect_success "setup $n bad commits" '
+	for i in $(test_seq 1 $n)
+	do
+		echo "commit refs/heads/master" &&
+		echo "committer C <c@example.com> 1234567890 +0000" &&
+		echo "data <<EOF" &&
+		echo "$i.Q." &&
+		echo "EOF"
+	done | q_to_nul | git fast-import
+'
+
+skip=0
+while test $skip -le $n
+do
+	test_expect_success "create skipList for $skip bad commits" '
+		git log --format=%H --max-count=$skip |
+		sort >skiplist
+	'
+
+	test_perf "fsck with $skip skipped bad commits" '
+		git -c fsck.skipList=skiplist fsck
+	'
+
+	case $skip in
+	0) skip=1 ;;
+	*) skip=${skip}0 ;;
+	esac
+done
+
+test_done
diff --git a/t/perf/p3400-rebase.sh b/t/perf/p3400-rebase.sh
new file mode 100755
index 000000000000..d202aaed06fc
--- /dev/null
+++ b/t/perf/p3400-rebase.sh
@@ -0,0 +1,56 @@
+#!/bin/sh
+
+test_description='Tests rebase performance'
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_expect_success 'setup rebasing on top of a lot of changes' '
+	git checkout -f -B base &&
+	git checkout -B to-rebase &&
+	git checkout -B upstream &&
+	for i in $(seq 100)
+	do
+		# simulate huge diffs
+		echo change$i >unrelated-file$i &&
+		seq 1000 >>unrelated-file$i &&
+		git add unrelated-file$i &&
+		test_tick &&
+		git commit -m commit$i unrelated-file$i &&
+		echo change$i >unrelated-file$i &&
+		seq 1000 | tac >>unrelated-file$i &&
+		git add unrelated-file$i &&
+		test_tick &&
+		git commit -m commit$i-reverse unrelated-file$i ||
+		break
+	done &&
+	git checkout to-rebase &&
+	test_commit our-patch interesting-file
+'
+
+test_perf 'rebase on top of a lot of unrelated changes' '
+	git rebase --onto upstream HEAD^ &&
+	git rebase --onto base HEAD^
+'
+
+test_expect_success 'setup rebasing many changes without split-index' '
+	git config core.splitIndex false &&
+	git checkout -B upstream2 to-rebase &&
+	git checkout -B to-rebase2 upstream
+'
+
+test_perf 'rebase a lot of unrelated changes without split-index' '
+	git rebase --onto upstream2 base &&
+	git rebase --onto base upstream2
+'
+
+test_expect_success 'setup rebasing many changes with split-index' '
+	git config core.splitIndex true
+'
+
+test_perf 'rebase a lot of unrelated changes with split-index' '
+	git rebase --onto upstream2 base &&
+	git rebase --onto base upstream2
+'
+
+test_done
diff --git a/t/perf/p3404-rebase-interactive.sh b/t/perf/p3404-rebase-interactive.sh
new file mode 100755
index 000000000000..88f47de282c1
--- /dev/null
+++ b/t/perf/p3404-rebase-interactive.sh
@@ -0,0 +1,36 @@
+#!/bin/sh
+
+test_description='Tests rebase -i performance'
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+# This commit merges a sufficiently long topic branch for reasonable
+# performance testing
+branch_merge=ba5312da19c6fdb6c6747d479f58932aae6e900c^{commit}
+export branch_merge
+
+git rev-parse --verify $branch_merge >/dev/null 2>&1 || {
+	skip_all='skipping because $branch_merge was not found'
+	test_done
+}
+
+write_script swap-first-two.sh <<\EOF
+case "$1" in
+*/COMMIT_EDITMSG)
+	mv "$1" "$1".bak &&
+	sed -e '1{h;d}' -e 2G <"$1".bak >"$1"
+	;;
+esac
+EOF
+
+test_expect_success 'setup' '
+	git config core.editor "\"$PWD"/swap-first-two.sh\" &&
+	git checkout -f $branch_merge^2
+'
+
+test_perf 'rebase -i' '
+	git rebase -i $branch_merge^
+'
+
+test_done
diff --git a/t/perf/p4000-diff-algorithms.sh b/t/perf/p4000-diff-algorithms.sh
new file mode 100755
index 000000000000..7e00c9da47d7
--- /dev/null
+++ b/t/perf/p4000-diff-algorithms.sh
@@ -0,0 +1,29 @@
+#!/bin/sh
+
+test_description="Tests diff generation performance"
+
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_perf 'log -3000 (baseline)' '
+	git log -3000 >/dev/null
+'
+
+test_perf 'log --raw -3000 (tree-only)' '
+	git log --raw -3000 >/dev/null
+'
+
+test_perf 'log -p -3000 (Myers)' '
+	git log -p -3000 >/dev/null
+'
+
+test_perf 'log -p -3000 --histogram' '
+	git log -p -3000 --histogram >/dev/null
+'
+
+test_perf 'log -p -3000 --patience' '
+	git log -p -3000 --patience >/dev/null
+'
+
+test_done
diff --git a/t/perf/p4001-diff-no-index.sh b/t/perf/p4001-diff-no-index.sh
new file mode 100755
index 000000000000..683be6984f5a
--- /dev/null
+++ b/t/perf/p4001-diff-no-index.sh
@@ -0,0 +1,22 @@
+#!/bin/sh
+
+test_description="Test diff --no-index performance"
+
+. ./perf-lib.sh
+
+test_perf_large_repo
+test_checkout_worktree
+
+file1=$(git ls-files | tail -n 2 | head -1)
+file2=$(git ls-files | tail -n 1 | head -1)
+
+test_expect_success "empty files, so they take no time to diff" "
+	echo >$file1 &&
+	echo >$file2
+"
+
+test_perf "diff --no-index" "
+	git diff --no-index $file1 $file2 >/dev/null
+"
+
+test_done
diff --git a/t/perf/p4205-log-pretty-formats.sh b/t/perf/p4205-log-pretty-formats.sh
new file mode 100755
index 000000000000..7c26f4f33788
--- /dev/null
+++ b/t/perf/p4205-log-pretty-formats.sh
@@ -0,0 +1,16 @@
+#!/bin/sh
+
+test_description='Tests the performance of various pretty format placeholders'
+
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+for format in %H %h %T %t %P %p %h-%h-%h
+do
+	test_perf "log with $format" "
+		git log --format=\"$format\" >/dev/null
+	"
+done
+
+test_done
diff --git a/t/perf/p4211-line-log.sh b/t/perf/p4211-line-log.sh
new file mode 100755
index 000000000000..392bcc0e51f8
--- /dev/null
+++ b/t/perf/p4211-line-log.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+
+test_description='Tests log -L performance'
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+# Pick a file to log pseudo-randomly.  The sort key is the blob hash,
+# so it is stable.
+test_expect_success 'select a file' '
+	git ls-tree HEAD | grep ^100644 |
+	sort -k 3 | head -1 | cut -f 2 >filelist
+'
+
+file=$(cat filelist)
+export file
+
+test_perf 'git rev-list --topo-order (baseline)' '
+	git rev-list --topo-order HEAD >/dev/null
+'
+
+test_perf 'git log --follow (baseline for -M)' '
+	git log --oneline --follow -- "$file" >/dev/null
+'
+
+test_perf 'git log -L (renames off)' '
+	git log --no-renames -L 1:"$file" >/dev/null
+'
+
+test_perf 'git log -L (renames on)' '
+	git log -M -L 1:"$file" >/dev/null
+'
+
+test_perf 'git log --oneline --raw --parents' '
+	git log --oneline --raw --parents >/dev/null
+'
+
+test_perf 'git log --oneline --raw --parents -1000' '
+	git log --oneline --raw --parents -1000 >/dev/null
+'
+
+test_done
diff --git a/t/perf/p4220-log-grep-engines.sh b/t/perf/p4220-log-grep-engines.sh
new file mode 100755
index 000000000000..2bc47ded4d11
--- /dev/null
+++ b/t/perf/p4220-log-grep-engines.sh
@@ -0,0 +1,53 @@
+#!/bin/sh
+
+test_description="Comparison of git-log's --grep regex engines
+
+Set GIT_PERF_4220_LOG_OPTS in the environment to pass options to
+git-grep. Make sure to include a leading space,
+e.g. GIT_PERF_4220_LOG_OPTS=' -i'. Some options to try:
+
+	-i
+	--invert-grep
+	-i --invert-grep
+"
+
+. ./perf-lib.sh
+
+test_perf_large_repo
+test_checkout_worktree
+
+for pattern in \
+	'how.to' \
+	'^how to' \
+	'[how] to' \
+	'\(e.t[^ ]*\|v.ry\) rare' \
+	'm\(ú\|u\)lt.b\(æ\|y\)te'
+do
+	for engine in basic extended perl
+	do
+		if test $engine != "basic"
+		then
+			# Poor man's basic -> extended converter.
+			pattern=$(echo $pattern | sed 's/\\//g')
+		fi
+		if test $engine = "perl" && ! test_have_prereq PCRE
+		then
+			prereq="PCRE"
+		else
+			prereq=""
+		fi
+		test_perf $prereq "$engine log$GIT_PERF_4220_LOG_OPTS --grep='$pattern'" "
+			git -c grep.patternType=$engine log --pretty=format:%h$GIT_PERF_4220_LOG_OPTS --grep='$pattern' >'out.$engine' || :
+		"
+	done
+
+	test_expect_success "assert that all engines found the same for$GIT_PERF_4220_LOG_OPTS '$pattern'" '
+		test_cmp out.basic out.extended &&
+		if test_have_prereq PCRE
+		then
+			test_cmp out.basic out.perl
+		fi
+	'
+done
+
+test_done
diff --git a/t/perf/p4221-log-grep-engines-fixed.sh b/t/perf/p4221-log-grep-engines-fixed.sh
new file mode 100755
index 000000000000..060971265a9c
--- /dev/null
+++ b/t/perf/p4221-log-grep-engines-fixed.sh
@@ -0,0 +1,44 @@
+#!/bin/sh
+
+test_description="Comparison of git-log's --grep regex engines with -F
+
+Set GIT_PERF_4221_LOG_OPTS in the environment to pass options to
+git-grep. Make sure to include a leading space,
+e.g. GIT_PERF_4221_LOG_OPTS=' -i'. Some options to try:
+
+	-i
+	--invert-grep
+	-i --invert-grep
+"
+
+. ./perf-lib.sh
+
+test_perf_large_repo
+test_checkout_worktree
+
+for pattern in 'int' 'uncommon' 'æ'
+do
+	for engine in fixed basic extended perl
+	do
+		if test $engine = "perl" && ! test_have_prereq PCRE
+		then
+			prereq="PCRE"
+		else
+			prereq=""
+		fi
+		test_perf $prereq "$engine log$GIT_PERF_4221_LOG_OPTS --grep='$pattern'" "
+			git -c grep.patternType=$engine log --pretty=format:%h$GIT_PERF_4221_LOG_OPTS --grep='$pattern' >'out.$engine' || :
+		"
+	done
+
+	test_expect_success "assert that all engines found the same for$GIT_PERF_4221_LOG_OPTS '$pattern'" '
+		test_cmp out.fixed out.basic &&
+		test_cmp out.fixed out.extended &&
+		if test_have_prereq PCRE
+		then
+			test_cmp out.fixed out.perl
+		fi
+	'
+done
+
+test_done
diff --git a/t/perf/p5302-pack-index.sh b/t/perf/p5302-pack-index.sh
new file mode 100755
index 000000000000..a9b3e112d982
--- /dev/null
+++ b/t/perf/p5302-pack-index.sh
@@ -0,0 +1,52 @@
+#!/bin/sh
+
+test_description="Tests index-pack performance"
+
+. ./perf-lib.sh
+
+test_perf_large_repo
+
+test_expect_success 'repack' '
+	git repack -ad &&
+	PACK=$(ls .git/objects/pack/*.pack | head -n1) &&
+	test -f "$PACK" &&
+	export PACK
+'
+
+test_perf 'index-pack 0 threads' '
+	rm -rf repo.git &&
+	git init --bare repo.git &&
+	GIT_DIR=repo.git git index-pack --threads=1 --stdin < $PACK
+'
+
+test_perf 'index-pack 1 thread ' '
+	rm -rf repo.git &&
+	git init --bare repo.git &&
+	GIT_DIR=repo.git GIT_FORCE_THREADS=1 git index-pack --threads=1 --stdin < $PACK
+'
+
+test_perf 'index-pack 2 threads' '
+	rm -rf repo.git &&
+	git init --bare repo.git &&
+	GIT_DIR=repo.git git index-pack --threads=2 --stdin < $PACK
+'
+
+test_perf 'index-pack 4 threads' '
+	rm -rf repo.git &&
+	git init --bare repo.git &&
+	GIT_DIR=repo.git git index-pack --threads=4 --stdin < $PACK
+'
+
+test_perf 'index-pack 8 threads' '
+	rm -rf repo.git &&
+	git init --bare repo.git &&
+	GIT_DIR=repo.git git index-pack --threads=8 --stdin < $PACK
+'
+
+test_perf 'index-pack default number of threads' '
+	rm -rf repo.git &&
+	git init --bare repo.git &&
+	GIT_DIR=repo.git git index-pack --stdin < $PACK
+'
+
+test_done
diff --git a/t/perf/p5303-many-packs.sh b/t/perf/p5303-many-packs.sh
new file mode 100755
index 000000000000..377985194116
--- /dev/null
+++ b/t/perf/p5303-many-packs.sh
@@ -0,0 +1,87 @@
+#!/bin/sh
+
+test_description='performance with large numbers of packs'
+. ./perf-lib.sh
+
+test_perf_large_repo
+
+# A real many-pack situation would probably come from having a lot of pushes
+# over time. We don't know how big each push would be, but we can fake it by
+# just walking the first-parent chain and having every 5 commits be their own
+# "push". This isn't _entirely_ accurate, as real pushes would have some
+# duplicate objects due to thin-pack fixing, but it's a reasonable
+# approximation.
+#
+# And then all of the rest of the objects can go in a single packfile that
+# represents the state before any of those pushes (actually, we'll generate
+# that first because in such a setup it would be the oldest pack, and we sort
+# the packs by reverse mtime inside git).
+repack_into_n () {
+	rm -rf staging &&
+	mkdir staging &&
+
+	git rev-list --first-parent HEAD |
+	sed -n '1~5p' |
+	head -n "$1" |
+	perl -e 'print reverse <>' \
+	>pushes
+
+	# create base packfile
+	head -n 1 pushes |
+	git pack-objects --delta-base-offset --revs staging/pack
+
+	# and then incrementals between each pair of commits
+	last= &&
+	while read rev
+	do
+		if test -n "$last"; then
+			{
+				echo "$rev" &&
+				echo "^$last"
+			} |
+			git pack-objects --delta-base-offset --revs \
+				staging/pack || return 1
+		fi
+		last=$rev
+	done <pushes &&
+
+	# and install the whole thing
+	rm -f .git/objects/pack/* &&
+	mv staging/* .git/objects/pack/
+}
+
+# Pretend we just have a single branch and no reflogs, and that everything is
+# in objects/pack; that makes our fake pack-building via repack_into_n()
+# much simpler.
+test_expect_success 'simplify reachability' '
+	tip=$(git rev-parse --verify HEAD) &&
+	git for-each-ref --format="option no-deref%0adelete %(refname)" |
+	git update-ref --stdin &&
+	rm -rf .git/logs &&
+	git update-ref refs/heads/master $tip &&
+	git symbolic-ref HEAD refs/heads/master &&
+	git repack -ad
+'
+
+for nr_packs in 1 50 1000
+do
+	test_expect_success "create $nr_packs-pack scenario" '
+		repack_into_n $nr_packs
+	'
+
+	test_perf "rev-list ($nr_packs)" '
+		git rev-list --objects --all >/dev/null
+	'
+
+	# This simulates the interesting part of the repack, which is the
+	# actual pack generation, without smudging the on-disk setup
+	# between trials.
+	test_perf "repack ($nr_packs)" '
+		git pack-objects --keep-true-parents \
+		  --honor-pack-keep --non-empty --all \
+		  --reflog --indexed-objects --delta-base-offset \
+		  --stdout </dev/null >/dev/null
+	'
+done
+
+test_done
diff --git a/t/perf/p5304-prune.sh b/t/perf/p5304-prune.sh
new file mode 100755
index 000000000000..83baedb8a492
--- /dev/null
+++ b/t/perf/p5304-prune.sh
@@ -0,0 +1,35 @@
+#!/bin/sh
+
+test_description='performance tests of prune'
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_expect_success 'remove reachable loose objects' '
+	git repack -ad
+'
+
+test_expect_success 'remove unreachable loose objects' '
+	git prune
+'
+
+test_expect_success 'confirm there are no loose objects' '
+	git count-objects | grep ^0
+'
+
+test_perf 'prune with no objects' '
+	git prune
+'
+
+test_expect_success 'repack with bitmaps' '
+	git repack -adb
+'
+
+# We have to create the object in each trial run, since otherwise
+# runs after the first see no object and just skip the traversal entirely!
+test_perf 'prune with bitmaps' '
+	echo "probably not present in repo" | git hash-object -w --stdin &&
+	git prune
+'
+
+test_done
diff --git a/t/perf/p5310-pack-bitmaps.sh b/t/perf/p5310-pack-bitmaps.sh
new file mode 100755
index 000000000000..6a3a42531b05
--- /dev/null
+++ b/t/perf/p5310-pack-bitmaps.sh
@@ -0,0 +1,71 @@
+#!/bin/sh
+
+test_description='Tests pack performance using bitmaps'
+. ./perf-lib.sh
+
+test_perf_large_repo
+
+# note that we do everything through config,
+# since we want to be able to compare bitmap-aware
+# git versus non-bitmap git
+#
+# We intentionally use the deprecated pack.writebitmaps
+# config so that we can test against older versions of git.
+test_expect_success 'setup bitmap config' '
+	git config pack.writebitmaps true
+'
+
+test_perf 'repack to disk' '
+	git repack -ad
+'
+
+test_perf 'simulated clone' '
+	git pack-objects --stdout --all </dev/null >/dev/null
+'
+
+test_perf 'simulated fetch' '
+	have=$(git rev-list HEAD~100 -1) &&
+	{
+		echo HEAD &&
+		echo ^$have
+	} | git pack-objects --revs --stdout >/dev/null
+'
+
+test_perf 'pack to file' '
+	git pack-objects --all pack1 </dev/null >/dev/null
+'
+
+test_perf 'pack to file (bitmap)' '
+	git pack-objects --use-bitmap-index --all pack1b </dev/null >/dev/null
+'
+
+test_expect_success 'create partial bitmap state' '
+	# pick a commit to represent the repo tip in the past
+	cutoff=$(git rev-list HEAD~100 -1) &&
+	orig_tip=$(git rev-parse HEAD) &&
+
+	# now kill off all of the refs and pretend we had
+	# just the one tip
+	rm -rf .git/logs .git/refs/* .git/packed-refs &&
+	git update-ref HEAD $cutoff &&
+
+	# and then repack, which will leave us with a nice
+	# big bitmap pack of the "old" history, and all of
+	# the new history will be loose, as if it had been pushed
+	# up incrementally and exploded via unpack-objects
+	git repack -Ad &&
+
+	# and now restore our original tip, as if the pushes
+	# had happened
+	git update-ref HEAD $orig_tip
+'
+
+test_perf 'clone (partial bitmap)' '
+	git pack-objects --stdout --all </dev/null >/dev/null
+'
+
+test_perf 'pack to file (partial bitmap)' '
+	git pack-objects --use-bitmap-index --all pack2b </dev/null >/dev/null
+'
+
+test_done
diff --git a/t/perf/p5311-pack-bitmaps-fetch.sh b/t/perf/p5311-pack-bitmaps-fetch.sh
new file mode 100755
index 000000000000..47c3fd7581cc
--- /dev/null
+++ b/t/perf/p5311-pack-bitmaps-fetch.sh
@@ -0,0 +1,44 @@
+#!/bin/sh
+
+test_description='performance of fetches from bitmapped packs'
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_expect_success 'create bitmapped server repo' '
+	git config pack.writebitmaps true &&
+	git repack -ad
+'
+
+# simulate a fetch from a repository that last fetched N days ago, for
+# various values of N. We do so by following the first-parent chain,
+# and assume the first entry in the chain that is N days older than the current
+# HEAD is where the HEAD would have been then.
+for days in 1 2 4 8 16 32 64 128; do
+	title=$(printf '%10s' "($days days)")
+	test_expect_success "setup revs from $days days ago" '
+		now=$(git log -1 --format=%ct HEAD) &&
+		then=$(($now - ($days * 86400))) &&
+		tip=$(git rev-list -1 --first-parent --until=$then HEAD) &&
+		{
+			echo HEAD &&
+			echo ^$tip
+		} >revs
+	'
+
+	test_perf "server $title" '
+		git pack-objects --stdout --revs \
+				 --thin --delta-base-offset \
+				 <revs >tmp.pack
+	'
+
+	test_size "size   $title" '
+		wc -c <tmp.pack
+	'
+
+	test_perf "client $title" '
+		git index-pack --stdin --fix-thin <tmp.pack
+	'
+done
+
+test_done
diff --git a/t/perf/p5550-fetch-tags.sh b/t/perf/p5550-fetch-tags.sh
new file mode 100755
index 000000000000..d0e0e019ea36
--- /dev/null
+++ b/t/perf/p5550-fetch-tags.sh
@@ -0,0 +1,78 @@
+#!/bin/sh
+
+test_description='performance of tag-following with many tags
+
+This tests a fairly pathological case, so rather than rely on a real-world
+case, we will construct our own repository. The situation is roughly as
+follows.
+
+The parent repository has a large number of tags which are disconnected from
+the rest of history. That makes them candidates for tag-following, but we never
+actually grab them (and thus they will impact each subsequent fetch).
+
+The child repository is a clone of parent, without the tags, and is at least
+one commit behind the parent (meaning that we will fetch one object and then
+examine the tags to see if they need followed). Furthermore, it has a large
+number of packs.
+
+The exact values of "large" here are somewhat arbitrary; I picked values that
+start to show a noticeable performance problem on my machine, but without
+taking too long to set up and run the tests.
+'
+. ./perf-lib.sh
+. "$TEST_DIRECTORY/perf/lib-pack.sh"
+
+# make a long nonsense history on branch $1, consisting of $2 commits, each
+# with a unique file pointing to the blob at $2.
+create_history () {
+	perl -le '
+		my ($branch, $n, $blob) = @ARGV;
+		for (1..$n) {
+			print "commit refs/heads/$branch";
+			print "committer nobody <nobody@example.com> now";
+			print "data 4";
+			print "foo";
+			print "M 100644 $blob $_";
+		}
+	' "$@" |
+	git fast-import --date-format=now
+}
+
+# make a series of tags, one per commit in the revision range given by $@
+create_tags () {
+	git rev-list "$@" |
+	perl -lne 'print "create refs/tags/$. $_"' |
+	git update-ref --stdin
+}
+
+test_expect_success 'create parent and child' '
+	git init parent &&
+	git -C parent commit --allow-empty -m base &&
+	git clone parent child &&
+	git -C parent commit --allow-empty -m trigger-fetch
+'
+
+test_expect_success 'populate parent tags' '
+	(
+		cd parent &&
+		blob=$(echo content | git hash-object -w --stdin) &&
+		create_history cruft 3000 $blob &&
+		create_tags cruft &&
+		git branch -D cruft
+	)
+'
+
+test_expect_success 'create child packs' '
+	(
+		cd child &&
+		setup_many_packs
+	)
+'
+
+test_perf 'fetch' '
+	# make sure there is something to fetch on each iteration
+	git -C child update-ref -d refs/remotes/origin/master &&
+	git -C child fetch
+'
+
+test_done
diff --git a/t/perf/p5551-fetch-rescan.sh b/t/perf/p5551-fetch-rescan.sh
new file mode 100755
index 000000000000..b99dc23e328d
--- /dev/null
+++ b/t/perf/p5551-fetch-rescan.sh
@@ -0,0 +1,55 @@
+#!/bin/sh
+
+test_description='fetch performance with many packs
+
+It is common for fetch to consider objects that we might not have, and it is an
+easy mistake for the code to use a function like `parse_object` that might
+give the correct _answer_ on such an object, but do so slowly (due to
+re-scanning the pack directory for lookup failures).
+
+The resulting performance drop can be hard to notice in a real repository, but
+becomes quite large in a repository with a large number of packs. So this
+test creates a more pathological case, since any mistakes would produce a more
+noticeable slowdown.
+'
+. ./perf-lib.sh
+. "$TEST_DIRECTORY"/perf/lib-pack.sh
+
+test_expect_success 'create parent and child' '
+	git init parent &&
+	git clone parent child
+'
+
+
+test_expect_success 'create refs in the parent' '
+	(
+		cd parent &&
+		git commit --allow-empty -m foo &&
+		head=$(git rev-parse HEAD) &&
+		test_seq 1000 |
+		sed "s,.*,update refs/heads/& $head," |
+		$MODERN_GIT update-ref --stdin
+	)
+'
+
+test_expect_success 'create many packs in the child' '
+	(
+		cd child &&
+		setup_many_packs
+	)
+'
+
+test_perf 'fetch' '
+	# start at the same state for each iteration
+	obj=$($MODERN_GIT -C parent rev-parse HEAD) &&
+	(
+		cd child &&
+		$MODERN_GIT for-each-ref --format="delete %(refname)" refs/remotes |
+		$MODERN_GIT update-ref --stdin &&
+		rm -vf .git/objects/$(echo $obj | sed "s|^..|&/|") &&
+
+		git fetch
+	)
+'
+
+test_done
diff --git a/t/perf/p5600-clone-reference.sh b/t/perf/p5600-clone-reference.sh
new file mode 100755
index 000000000000..68fed663479d
--- /dev/null
+++ b/t/perf/p5600-clone-reference.sh
@@ -0,0 +1,27 @@
+#!/bin/sh
+
+test_description='speed of clone --reference'
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_expect_success 'create shareable repository' '
+	git clone --bare . shared.git
+'
+
+test_expect_success 'advance base repository' '
+	# Do not use test_commit here; its test_tick will
+	# use some ancient hard-coded date. The resulting clock
+	# skew will cause pack-objects to traverse in a very
+	# sub-optimal order, skewing the results.
+	echo content >new-file-that-does-not-exist &&
+	git add new-file-that-does-not-exist &&
+	git commit -m "new commit"
+'
+
+test_perf 'clone --reference' '
+	rm -rf dst.git &&
+	git clone --no-local --bare --reference shared.git . dst.git
+'
+
+test_done
diff --git a/t/perf/p5600-partial-clone.sh b/t/perf/p5600-partial-clone.sh
new file mode 100755
index 000000000000..3e04bd2ae1d6
--- /dev/null
+++ b/t/perf/p5600-partial-clone.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+
+test_description='performance of partial clones'
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_expect_success 'enable server-side config' '
+	git config uploadpack.allowFilter true &&
+	git config uploadpack.allowAnySHA1InWant true
+'
+
+test_perf 'clone without blobs' '
+	rm -rf bare.git &&
+	git clone --no-local --bare --filter=blob:none . bare.git
+'
+
+test_perf 'checkout of result' '
+	rm -rf worktree &&
+	mkdir -p worktree/.git &&
+	tar -C bare.git -cf - . | tar -C worktree/.git -xf - &&
+	git -C worktree config core.bare false &&
+	git -C worktree checkout -f
+'
+
+test_done
diff --git a/t/perf/p7000-filter-branch.sh b/t/perf/p7000-filter-branch.sh
new file mode 100755
index 000000000000..b029586ccb2c
--- /dev/null
+++ b/t/perf/p7000-filter-branch.sh
@@ -0,0 +1,24 @@
+#!/bin/sh
+
+test_description='performance of filter-branch'
+. ./perf-lib.sh
+
+test_perf_default_repo
+test_checkout_worktree
+
+test_expect_success 'mark bases for tests' '
+	git tag -f tip &&
+	git tag -f base HEAD~100
+'
+
+test_perf 'noop filter' '
+	git checkout --detach tip &&
+	git filter-branch -f base..HEAD
+'
+
+test_perf 'noop prune-empty' '
+	git checkout --detach tip &&
+	git filter-branch -f --prune-empty base..HEAD
+'
+
+test_done
diff --git a/t/perf/p7300-clean.sh b/t/perf/p7300-clean.sh
new file mode 100755
index 000000000000..7c1888a27e7f
--- /dev/null
+++ b/t/perf/p7300-clean.sh
@@ -0,0 +1,35 @@
+#!/bin/sh
+
+test_description="Test git-clean performance"
+
+. ./perf-lib.sh
+
+test_perf_default_repo
+test_checkout_worktree
+
+test_expect_success 'setup untracked directory with many sub dirs' '
+	rm -rf 500_sub_dirs 100000_sub_dirs clean_test_dir &&
+	mkdir 500_sub_dirs 100000_sub_dirs clean_test_dir &&
+	for i in $(test_seq 1 500)
+	do
+		mkdir 500_sub_dirs/dir$i || return $?
+	done &&
+	for i in $(test_seq 1 200)
+	do
+		cp -r 500_sub_dirs 100000_sub_dirs/dir$i || return $?
+	done
+'
+
+test_perf 'clean many untracked sub dirs, check for nested git' '
+	git clean -n -q -f -d 100000_sub_dirs/
+'
+
+test_perf 'clean many untracked sub dirs, ignore nested git' '
+	git clean -n -q -f -f -d 100000_sub_dirs/
+'
+
+test_perf 'ls-files -o' '
+	git ls-files -o
+'
+
+test_done
diff --git a/t/perf/p7519-fsmonitor.sh b/t/perf/p7519-fsmonitor.sh
new file mode 100755
index 000000000000..def7ecdbc786
--- /dev/null
+++ b/t/perf/p7519-fsmonitor.sh
@@ -0,0 +1,183 @@
+#!/bin/sh
+
+test_description="Test core.fsmonitor"
+
+. ./perf-lib.sh
+
+#
+# Performance test for the fsmonitor feature which enables git to talk to a
+# file system change monitor and avoid having to scan the working directory
+# for new or modified files.
+#
+# By default, the performance test will utilize the Watchman file system
+# monitor if it is installed.  If Watchman is not installed, it will use a
+# dummy integration script that does not report any new or modified files.
+# The dummy script has very little overhead which provides optimistic results.
+#
+# The performance test will also use the untracked cache feature if it is
+# available as fsmonitor uses it to speed up scanning for untracked files.
+#
+# There are 3 environment variables that can be used to alter the default
+# behavior of the performance test:
+#
+# GIT_PERF_7519_UNTRACKED_CACHE: used to configure core.untrackedCache
+# GIT_PERF_7519_SPLIT_INDEX: used to configure core.splitIndex
+# GIT_PERF_7519_FSMONITOR: used to configure core.fsMonitor
+#
+# The big win for using fsmonitor is the elimination of the need to scan the
+# working directory looking for changed and untracked files. If the file
+# information is all cached in RAM, the benefits are reduced.
+#
+# GIT_PERF_7519_DROP_CACHE: if set, the OS caches are dropped between tests
+#
+
+test_perf_large_repo
+test_checkout_worktree
+
+test_lazy_prereq UNTRACKED_CACHE '
+	{ git update-index --test-untracked-cache; ret=$?; } &&
+	test $ret -ne 1
+'
+
+test_lazy_prereq WATCHMAN '
+	command -v watchman
+'
+
+if test_have_prereq WATCHMAN
+then
+	# Convert unix style paths to escaped Windows style paths for Watchman
+	case "$(uname -s)" in
+	MSYS_NT*)
+	  GIT_WORK_TREE="$(cygpath -aw "$PWD" | sed 's,\\,/,g')"
+	  ;;
+	*)
+	  GIT_WORK_TREE="$PWD"
+	  ;;
+	esac
+fi
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"
+then
+	# When using GIT_PERF_7519_DROP_CACHE, GIT_PERF_REPEAT_COUNT must be 1 to
+	# generate valid results. Otherwise the caching that happens for the nth
+	# run will negate the validity of the comparisons.
+	if test "$GIT_PERF_REPEAT_COUNT" -ne 1
+	then
+		echo "warning: Setting GIT_PERF_REPEAT_COUNT=1" >&2
+		GIT_PERF_REPEAT_COUNT=1
+	fi
+fi
+
+test_expect_success "setup for fsmonitor" '
+	# set untrackedCache depending on the environment
+	if test -n "$GIT_PERF_7519_UNTRACKED_CACHE"
+	then
+		git config core.untrackedCache "$GIT_PERF_7519_UNTRACKED_CACHE"
+	else
+		if test_have_prereq UNTRACKED_CACHE
+		then
+			git config core.untrackedCache true
+		else
+			git config core.untrackedCache false
+		fi
+	fi &&
+
+	# set core.splitindex depending on the environment
+	if test -n "$GIT_PERF_7519_SPLIT_INDEX"
+	then
+		git config core.splitIndex "$GIT_PERF_7519_SPLIT_INDEX"
+	fi &&
+
+	# set INTEGRATION_SCRIPT depending on the environment
+	if test -n "$GIT_PERF_7519_FSMONITOR"
+	then
+		INTEGRATION_SCRIPT="$GIT_PERF_7519_FSMONITOR"
+	else
+		#
+		# Choose integration script based on existence of Watchman.
+		# If Watchman exists, watch the work tree and attempt a query.
+		# If everything succeeds, use Watchman integration script,
+		# else fall back to an empty integration script.
+		#
+		mkdir .git/hooks &&
+		if test_have_prereq WATCHMAN
+		then
+			INTEGRATION_SCRIPT=".git/hooks/fsmonitor-watchman" &&
+			cp "$TEST_DIRECTORY/../templates/hooks--fsmonitor-watchman.sample" "$INTEGRATION_SCRIPT" &&
+			watchman watch "$GIT_WORK_TREE" &&
+			watchman watch-list | grep -q -F "$GIT_WORK_TREE"
+		else
+			INTEGRATION_SCRIPT=".git/hooks/fsmonitor-empty" &&
+			write_script "$INTEGRATION_SCRIPT"<<-\EOF
+			EOF
+		fi
+	fi &&
+
+	git config core.fsmonitor "$INTEGRATION_SCRIPT" &&
+	git update-index --fsmonitor
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-tool drop-caches
+fi
+
+test_perf "status (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-tool drop-caches
+fi
+
+test_perf "status -uno (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status -uno
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-tool drop-caches
+fi
+
+test_perf "status -uall (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status -uall
+'
+
+test_expect_success "setup without fsmonitor" '
+	unset INTEGRATION_SCRIPT &&
+	git config --unset core.fsmonitor &&
+	git update-index --no-fsmonitor
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-tool drop-caches
+fi
+
+test_perf "status (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-tool drop-caches
+fi
+
+test_perf "status -uno (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status -uno
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-tool drop-caches
+fi
+
+test_perf "status -uall (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status -uall
+'
+
+if test_have_prereq WATCHMAN
+then
+	watchman watch-del "$GIT_WORK_TREE" >/dev/null 2>&1 &&
+
+	# Work around Watchman bug on Windows where it holds on to handles
+	# preventing the removal of the trash directory
+	watchman shutdown-server >/dev/null 2>&1
+fi
+
+test_done
diff --git a/t/perf/p7810-grep.sh b/t/perf/p7810-grep.sh
new file mode 100755
index 000000000000..9f4ade639f74
--- /dev/null
+++ b/t/perf/p7810-grep.sh
@@ -0,0 +1,23 @@
+#!/bin/sh
+
+test_description="git-grep performance in various modes"
+
+. ./perf-lib.sh
+
+test_perf_large_repo
+test_checkout_worktree
+
+test_perf 'grep worktree, cheap regex' '
+	git grep some_nonexistent_string || :
+'
+test_perf 'grep worktree, expensive regex' '
+	git grep "^.* *some_nonexistent_string$" || :
+'
+test_perf 'grep --cached, cheap regex' '
+	git grep --cached some_nonexistent_string || :
+'
+test_perf 'grep --cached, expensive regex' '
+	git grep --cached "^.* *some_nonexistent_string$" || :
+'
+
+test_done
diff --git a/t/perf/p7820-grep-engines.sh b/t/perf/p7820-grep-engines.sh
new file mode 100755
index 000000000000..8b09c5bf328b
--- /dev/null
+++ b/t/perf/p7820-grep-engines.sh
@@ -0,0 +1,88 @@
+#!/bin/sh
+
+test_description="Comparison of git-grep's regex engines
+
+Set GIT_PERF_7820_GREP_OPTS in the environment to pass options to
+git-grep. Make sure to include a leading space,
+e.g. GIT_PERF_7820_GREP_OPTS=' -i'. Some options to try:
+
+	-i
+	-w
+	-v
+	-vi
+	-vw
+	-viw
+
+If GIT_PERF_GREP_THREADS is set to a list of threads (e.g. '1 4 8'
+etc.) we will test the patterns under those numbers of threads.
+"
+
+. ./perf-lib.sh
+
+test_perf_large_repo
+test_checkout_worktree
+
+if test -n "$GIT_PERF_GREP_THREADS"
+then
+	test_set_prereq PERF_GREP_ENGINES_THREADS
+fi
+
+for pattern in \
+	'how.to' \
+	'^how to' \
+	'[how] to' \
+	'\(e.t[^ ]*\|v.ry\) rare' \
+	'm\(ú\|u\)lt.b\(æ\|y\)te'
+do
+	for engine in basic extended perl
+	do
+		if test $engine != "basic"
+		then
+			# Poor man's basic -> extended converter.
+			pattern=$(echo "$pattern" | sed 's/\\//g')
+		fi
+		if test $engine = "perl" && ! test_have_prereq PCRE
+		then
+			prereq="PCRE"
+		else
+			prereq=""
+		fi
+		if ! test_have_prereq PERF_GREP_ENGINES_THREADS
+		then
+			test_perf $prereq "$engine grep$GIT_PERF_7820_GREP_OPTS '$pattern'" "
+				git -c grep.patternType=$engine grep$GIT_PERF_7820_GREP_OPTS -- '$pattern' >'out.$engine' || :
+			"
+		else
+			for threads in $GIT_PERF_GREP_THREADS
+			do
+				test_perf PTHREADS,$prereq "$engine grep$GIT_PERF_7820_GREP_OPTS '$pattern' with $threads threads" "
+					git -c grep.patternType=$engine -c grep.threads=$threads grep$GIT_PERF_7820_GREP_OPTS -- '$pattern' >'out.$engine.$threads' || :
+				"
+			done
+		fi
+	done
+
+	if ! test_have_prereq PERF_GREP_ENGINES_THREADS
+	then
+		test_expect_success "assert that all engines found the same for$GIT_PERF_7820_GREP_OPTS '$pattern'" '
+			test_cmp out.basic out.extended &&
+			if test_have_prereq PCRE
+			then
+				test_cmp out.basic out.perl
+			fi
+		'
+	else
+		for threads in $GIT_PERF_GREP_THREADS
+		do
+			test_expect_success PTHREADS "assert that all engines found the same for$GIT_PERF_7820_GREP_OPTS '$pattern' under threading" "
+				test_cmp out.basic.$threads out.extended.$threads &&
+				if test_have_prereq PCRE
+				then
+					test_cmp out.basic.$threads out.perl.$threads
+				fi
+			"
+		done
+	fi
+done
+
+test_done
diff --git a/t/perf/p7821-grep-engines-fixed.sh b/t/perf/p7821-grep-engines-fixed.sh
new file mode 100755
index 000000000000..61e41b82cffa
--- /dev/null
+++ b/t/perf/p7821-grep-engines-fixed.sh
@@ -0,0 +1,74 @@
+#!/bin/sh
+
+test_description="Comparison of git-grep's regex engines with -F
+
+Set GIT_PERF_7821_GREP_OPTS in the environment to pass options to
+git-grep. Make sure to include a leading space,
+e.g. GIT_PERF_7821_GREP_OPTS=' -w'. See p7820-grep-engines.sh for more
+options to try.
+
+If GIT_PERF_7821_THREADS is set to a list of threads (e.g. '1 4 8'
+etc.) we will test the patterns under those numbers of threads.
+"
+
+. ./perf-lib.sh
+
+test_perf_large_repo
+test_checkout_worktree
+
+if test -n "$GIT_PERF_GREP_THREADS"
+then
+	test_set_prereq PERF_GREP_ENGINES_THREADS
+fi
+
+for pattern in 'int' 'uncommon' 'æ'
+do
+	for engine in fixed basic extended perl
+	do
+		if test $engine = "perl" && ! test_have_prereq PCRE
+		then
+			prereq="PCRE"
+		else
+			prereq=""
+		fi
+		if ! test_have_prereq PERF_GREP_ENGINES_THREADS
+		then
+			test_perf $prereq "$engine grep$GIT_PERF_7821_GREP_OPTS $pattern" "
+				git -c grep.patternType=$engine grep$GIT_PERF_7821_GREP_OPTS $pattern >'out.$engine' || :
+			"
+		else
+			for threads in $GIT_PERF_GREP_THREADS
+			do
+				test_perf PTHREADS,$prereq "$engine grep$GIT_PERF_7821_GREP_OPTS $pattern with $threads threads" "
+					git -c grep.patternType=$engine -c grep.threads=$threads grep$GIT_PERF_7821_GREP_OPTS $pattern >'out.$engine.$threads' || :
+				"
+			done
+		fi
+	done
+
+	if ! test_have_prereq PERF_GREP_ENGINES_THREADS
+	then
+		test_expect_success "assert that all engines found the same for$GIT_PERF_7821_GREP_OPTS $pattern" '
+			test_cmp out.fixed out.basic &&
+			test_cmp out.fixed out.extended &&
+			if test_have_prereq PCRE
+			then
+				test_cmp out.fixed out.perl
+			fi
+		'
+	else
+		for threads in $GIT_PERF_GREP_THREADS
+		do
+			test_expect_success PTHREADS "assert that all engines found the same for$GIT_PERF_7821_GREP_OPTS $pattern under threading" "
+				test_cmp out.fixed.$threads out.basic.$threads &&
+				test_cmp out.fixed.$threads out.extended.$threads &&
+				if test_have_prereq PCRE
+				then
+					test_cmp out.fixed.$threads out.perl.$threads
+				fi
+			"
+		done
+	fi
+done
+
+test_done
diff --git a/t/perf/perf-lib.sh b/t/perf/perf-lib.sh
new file mode 100644
index 000000000000..b58a43ea4364
--- /dev/null
+++ b/t/perf/perf-lib.sh
@@ -0,0 +1,247 @@
+# Performance testing framework.  Each perf script starts much like
+# a normal test script, except it sources this library instead of
+# test-lib.sh.  See t/perf/README for documentation.
+#
+# Copyright (c) 2011 Thomas Rast
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see http://www.gnu.org/licenses/ .
+
+# These variables must be set before the inclusion of test-lib.sh below,
+# because it will change our working directory.
+TEST_DIRECTORY=$(pwd)/..
+TEST_OUTPUT_DIRECTORY=$(pwd)
+
+TEST_NO_CREATE_REPO=t
+TEST_NO_MALLOC_CHECK=t
+
+. ../test-lib.sh
+
+if test -n "$GIT_TEST_INSTALLED" -a -z "$PERF_SET_GIT_TEST_INSTALLED"
+then
+	error "Do not use GIT_TEST_INSTALLED with the perf tests.
+
+Instead use:
+
+    ./run <path-to-git> -- <tests>
+
+See t/perf/README for details."
+fi
+
+# Variables from test-lib that are normally internal to the tests; we
+# need to export them for test_perf subshells
+export TEST_DIRECTORY TRASH_DIRECTORY GIT_BUILD_DIR GIT_TEST_CMP
+
+MODERN_GIT=$GIT_BUILD_DIR/bin-wrappers/git
+export MODERN_GIT
+
+perf_results_dir=$TEST_OUTPUT_DIRECTORY/test-results
+test -n "$GIT_PERF_SUBSECTION" && perf_results_dir="$perf_results_dir/$GIT_PERF_SUBSECTION"
+mkdir -p "$perf_results_dir"
+rm -f "$perf_results_dir"/$(basename "$0" .sh).subtests
+
+die_if_build_dir_not_repo () {
+	if ! ( cd "$TEST_DIRECTORY/.." &&
+		    git rev-parse --build-dir >/dev/null 2>&1 ); then
+		error "No $1 defined, and your build directory is not a repo"
+	fi
+}
+
+if test -z "$GIT_PERF_REPO"; then
+	die_if_build_dir_not_repo '$GIT_PERF_REPO'
+	GIT_PERF_REPO=$TEST_DIRECTORY/..
+fi
+if test -z "$GIT_PERF_LARGE_REPO"; then
+	die_if_build_dir_not_repo '$GIT_PERF_LARGE_REPO'
+	GIT_PERF_LARGE_REPO=$TEST_DIRECTORY/..
+fi
+
+test_perf_do_repo_symlink_config_ () {
+	test_have_prereq SYMLINKS || git config core.symlinks false
+}
+
+test_perf_create_repo_from () {
+	test "$#" = 2 ||
+	BUG "not 2 parameters to test-create-repo"
+	repo="$1"
+	source="$2"
+	source_git="$("$MODERN_GIT" -C "$source" rev-parse --git-dir)"
+	objects_dir="$("$MODERN_GIT" -C "$source" rev-parse --git-path objects)"
+	mkdir -p "$repo/.git"
+	(
+		cd "$source" &&
+		{ cp -Rl "$objects_dir" "$repo/.git/" 2>/dev/null ||
+			cp -R "$objects_dir" "$repo/.git/"; } &&
+		for stuff in "$source_git"/*; do
+			case "$stuff" in
+				*/objects|*/hooks|*/config|*/commondir)
+					;;
+				*)
+					cp -R "$stuff" "$repo/.git/" || exit 1
+					;;
+			esac
+		done
+	) &&
+	(
+		cd "$repo" &&
+		"$MODERN_GIT" init -q &&
+		test_perf_do_repo_symlink_config_ &&
+		mv .git/hooks .git/hooks-disabled 2>/dev/null &&
+		if test -f .git/index.lock
+		then
+			# We may be copying a repo that can't run "git
+			# status" due to a locked index. Since we have
+			# a copy it's fine to remove the lock.
+			rm .git/index.lock
+		fi
+	) || error "failed to copy repository '$source' to '$repo'"
+}
+
+# call at least one of these to establish an appropriately-sized repository
+test_perf_fresh_repo () {
+	repo="${1:-$TRASH_DIRECTORY}"
+	"$MODERN_GIT" init -q "$repo" &&
+	(
+		cd "$repo" &&
+		test_perf_do_repo_symlink_config_
+	)
+}
+
+test_perf_default_repo () {
+	test_perf_create_repo_from "${1:-$TRASH_DIRECTORY}" "$GIT_PERF_REPO"
+}
+test_perf_large_repo () {
+	if test "$GIT_PERF_LARGE_REPO" = "$GIT_BUILD_DIR"; then
+		echo "warning: \$GIT_PERF_LARGE_REPO is \$GIT_BUILD_DIR." >&2
+		echo "warning: This will work, but may not be a sufficiently large repo" >&2
+		echo "warning: for representative measurements." >&2
+	fi
+	test_perf_create_repo_from "${1:-$TRASH_DIRECTORY}" "$GIT_PERF_LARGE_REPO"
+}
+test_checkout_worktree () {
+	git checkout-index -u -a ||
+	error "git checkout-index failed"
+}
+
+# Performance tests should never fail.  If they do, stop immediately
+immediate=t
+
+# Perf tests require GNU time
+case "$(uname -s)" in Darwin) GTIME="${GTIME:-gtime}";; esac
+GTIME="${GTIME:-/usr/bin/time}"
+
+test_run_perf_ () {
+	test_cleanup=:
+	test_export_="test_cleanup"
+	export test_cleanup test_export_
+	"$GTIME" -f "%E %U %S" -o test_time.$i "$SHELL" -c '
+. '"$TEST_DIRECTORY"/test-lib-functions.sh'
+test_export () {
+	[ $# != 0 ] || return 0
+	test_export_="$test_export_\\|$1"
+	shift
+	test_export "$@"
+}
+'"$1"'
+ret=$?
+set | sed -n "s'"/'/'\\\\''/g"';s/^\\($test_export_\\)/export '"'&'"'/p" >test_vars
+exit $ret' >&3 2>&4
+	eval_ret=$?
+
+	if test $eval_ret = 0 || test -n "$expecting_failure"
+	then
+		test_eval_ "$test_cleanup"
+		. ./test_vars || error "failed to load updated environment"
+	fi
+	if test "$verbose" = "t" && test -n "$HARNESS_ACTIVE"; then
+		echo ""
+	fi
+	return "$eval_ret"
+}
+
+test_wrapper_ () {
+	test_wrapper_func_=$1; shift
+	test_start_
+	test "$#" = 3 && { test_prereq=$1; shift; } || test_prereq=
+	test "$#" = 2 ||
+	BUG "not 2 or 3 parameters to test-expect-success"
+	export test_prereq
+	if ! test_skip "$@"
+	then
+		base=$(basename "$0" .sh)
+		echo "$test_count" >>"$perf_results_dir"/$base.subtests
+		echo "$1" >"$perf_results_dir"/$base.$test_count.descr
+		base="$perf_results_dir"/"$PERF_RESULTS_PREFIX$(basename "$0" .sh)"."$test_count"
+		"$test_wrapper_func_" "$@"
+	fi
+
+	test_finish_
+}
+
+test_perf_ () {
+	if test -z "$verbose"; then
+		printf "%s" "perf $test_count - $1:"
+	else
+		echo "perf $test_count - $1:"
+	fi
+	for i in $(test_seq 1 $GIT_PERF_REPEAT_COUNT); do
+		say >&3 "running: $2"
+		if test_run_perf_ "$2"
+		then
+			if test -z "$verbose"; then
+				printf " %s" "$i"
+			else
+				echo "* timing run $i/$GIT_PERF_REPEAT_COUNT:"
+			fi
+		else
+			test -z "$verbose" && echo
+			test_failure_ "$@"
+			break
+		fi
+	done
+	if test -z "$verbose"; then
+		echo " ok"
+	else
+		test_ok_ "$1"
+	fi
+	"$TEST_DIRECTORY"/perf/min_time.perl test_time.* >"$base".times
+}
+
+test_perf () {
+	test_wrapper_ test_perf_ "$@"
+}
+
+test_size_ () {
+	say >&3 "running: $2"
+	if test_eval_ "$2" 3>"$base".size; then
+		test_ok_ "$1"
+	else
+		test_failure_ "$@"
+	fi
+}
+
+test_size () {
+	test_wrapper_ test_size_ "$@"
+}
+
+# We extend test_done to print timings at the end (./run disables this
+# and does it after running everything)
+test_at_end_hook_ () {
+	if test -z "$GIT_PERF_AGGREGATING_LATER"; then
+		( cd "$TEST_DIRECTORY"/perf && ./aggregate.perl $(basename "$0") )
+	fi
+}
+
+test_export () {
+	export "$@"
+}
diff --git a/t/perf/repos/.gitignore b/t/perf/repos/.gitignore
new file mode 100644
index 000000000000..72e3dc3e1947
--- /dev/null
+++ b/t/perf/repos/.gitignore
@@ -0,0 +1 @@
+gen-*/
diff --git a/t/perf/repos/inflate-repo.sh b/t/perf/repos/inflate-repo.sh
new file mode 100755
index 000000000000..fcfc992b5b02
--- /dev/null
+++ b/t/perf/repos/inflate-repo.sh
@@ -0,0 +1,85 @@
+#!/bin/sh
+# Inflate the size of an EXISTING repo.
+#
+# This script should be run inside the worktree of a TEST repo.
+# It will use the contents of the current HEAD to generate a
+# commit containing copies of the current worktree such that the
+# total size of the commit has at least <target_size> files.
+#
+# Usage: [-t target_size] [-b branch_name]
+
+set -e
+
+target_size=10000
+branch_name=p0006-ballast
+ballast=ballast
+
+while test "$#" -ne 0
+do
+    case "$1" in
+	-b)
+	    shift;
+	    test "$#" -ne 0 || { echo 'error: -b requires an argument' >&2; exit 1; }
+	    branch_name=$1;
+	    shift ;;
+	-t)
+	    shift;
+	    test "$#" -ne 0 || { echo 'error: -t requires an argument' >&2; exit 1; }
+	    target_size=$1;
+	    shift ;;
+	*)
+	    echo "error: unknown option '$1'" >&2; exit 1 ;;
+    esac
+done
+
+git ls-tree -r HEAD >GEN_src_list
+nr_src_files=$(cat GEN_src_list | wc -l)
+
+src_branch=$(git symbolic-ref --short HEAD)
+
+echo "Branch $src_branch initially has $nr_src_files files."
+
+if test $target_size -le $nr_src_files
+then
+    echo "Repository already exceeds target size $target_size."
+    rm GEN_src_list
+    exit 1
+fi
+
+# Create well-known branch and add 1 file change to start
+# if off before the ballast.
+git checkout -b $branch_name HEAD
+echo "$target_size" > inflate-repo.params
+git add inflate-repo.params
+git commit -q -m params
+
+# Create ballast for in our branch.
+copy=1
+nr_files=$nr_src_files
+while test $nr_files -lt $target_size
+do
+    sed -e "s|	|	$ballast/$copy/|" <GEN_src_list |
+	git update-index --index-info
+
+    nr_files=$(expr $nr_files + $nr_src_files)
+    copy=$(expr $copy + 1)
+done
+rm GEN_src_list
+git commit -q -m "ballast"
+
+# Modify 1 file and commit.
+echo "$target_size" >> inflate-repo.params
+git add inflate-repo.params
+git commit -q -m "ballast plus 1"
+
+nr_files=$(git ls-files | wc -l)
+
+# Checkout master to put repo in canonical state (because
+# the perf test may need to clone and enable sparse-checkout
+# before attempting to checkout a commit with the ballast
+# (because it may contain 100K directories and 1M files)).
+git checkout $src_branch
+
+echo "Repository inflated. Branch $branch_name has $nr_files files."
+
+exit 0
diff --git a/t/perf/repos/many-files.sh b/t/perf/repos/many-files.sh
new file mode 100755
index 000000000000..28720e4e1041
--- /dev/null
+++ b/t/perf/repos/many-files.sh
@@ -0,0 +1,110 @@
+#!/bin/sh
+# Generate test data repository using the given parameters.
+# When omitted, we create "gen-many-files-d-w-f.git".
+#
+# Usage: [-r repo] [-d depth] [-w width] [-f files]
+#
+# -r repo: path to the new repo to be generated
+# -d depth: the depth of sub-directories
+# -w width: the number of sub-directories at each level
+# -f files: the number of files created in each directory
+#
+# Note that all files will have the same SHA-1 and each
+# directory at a level will have the same SHA-1, so we
+# will potentially have a large index, but not a large
+# ODB.
+#
+# Ballast will be created under "ballast/".
+
+EMPTY_BLOB=e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
+
+set -e
+
+# (5, 10, 9) will create 999,999 ballast files.
+# (4, 10, 9) will create  99,999 ballast files.
+depth=5
+width=10
+files=9
+
+while test "$#" -ne 0
+do
+    case "$1" in
+	-r)
+	    shift;
+	    test "$#" -ne 0 || { echo 'error: -r requires an argument' >&2; exit 1; }
+	    repo=$1;
+	    shift ;;
+	-d)
+	    shift;
+	    test "$#" -ne 0 || { echo 'error: -d requires an argument' >&2; exit 1; }
+	    depth=$1;
+	    shift ;;
+	-w)
+	    shift;
+	    test "$#" -ne 0 || { echo 'error: -w requires an argument' >&2; exit 1; }
+	    width=$1;
+	    shift ;;
+	-f)
+	    shift;
+	    test "$#" -ne 0 || { echo 'error: -f requires an argument' >&2; exit 1; }
+	    files=$1;
+	    shift ;;
+	*)
+	    echo "error: unknown option '$1'" >&2; exit 1 ;;
+	esac
+done
+
+# Inflate the index with thousands of empty files.
+# usage: dir depth width files
+fill_index() {
+	awk -v arg_dir=$1 -v arg_depth=$2 -v arg_width=$3 -v arg_files=$4 '
+		function make_paths(dir, depth, width, files, f, w) {
+			for (f = 1; f <= files; f++) {
+				print dir "/file" f
+			}
+			if (depth > 0) {
+				for (w = 1; w <= width; w++) {
+					make_paths(dir "/dir" w, depth - 1, width, files)
+				}
+			}
+		}
+		END { make_paths(arg_dir, arg_depth, arg_width, arg_files) }
+		' </dev/null |
+	sed "s/^/100644 $EMPTY_BLOB	/" |
+	git update-index --index-info
+	return 0
+}
+
+[ -z "$repo" ] && repo=gen-many-files-$depth.$width.$files.git
+
+mkdir $repo
+cd $repo
+git init .
+
+# Create an initial commit just to define master.
+touch many-files.empty
+echo "$depth $width $files" >many-files.params
+git add many-files.*
+git commit -q -m params
+
+# Create ballast for p0006 based upon the given params and
+# inflate the index with thousands of empty files and commit.
+git checkout -b p0006-ballast
+fill_index "ballast" $depth $width $files
+git commit -q -m "ballast"
+
+nr_files=$(git ls-files | wc -l)
+
+# Modify 1 file and commit.
+echo "$depth $width $files" >>many-files.params
+git add many-files.params
+git commit -q -m "ballast plus 1"
+
+# Checkout master to put repo in canonical state (because
+# the perf test may need to clone and enable sparse-checkout
+# before attempting to checkout a commit with the ballast
+# (because it may contain 100K directories and 1M files)).
+git checkout master
+
+echo "Repository "$repo" ($depth, $width, $files) created.  Ballast $nr_files."
+exit 0
diff --git a/t/perf/run b/t/perf/run
new file mode 100755
index 000000000000..c7b86104e12a
--- /dev/null
+++ b/t/perf/run
@@ -0,0 +1,247 @@
+#!/bin/sh
+
+die () {
+	echo >&2 "error: $*"
+	exit 1
+}
+
+while [ $# -gt 0 ]; do
+	arg="$1"
+	case "$arg" in
+	--)
+		break ;;
+	--help)
+		echo "usage: $0 [--config file] [--subsection subsec] [other_git_tree...] [--] [test_scripts]"
+		exit 0 ;;
+	--config)
+		shift
+		GIT_PERF_CONFIG_FILE=$(cd "$(dirname "$1")"; pwd)/$(basename "$1")
+		export GIT_PERF_CONFIG_FILE
+		shift ;;
+	--subsection)
+		shift
+		GIT_PERF_SUBSECTION="$1"
+		export GIT_PERF_SUBSECTION
+		shift ;;
+	--*)
+		die "unrecognised option: '$arg'" ;;
+	*)
+		break ;;
+	esac
+done
+
+run_one_dir () {
+	if test $# -eq 0; then
+		set -- p????-*.sh
+	fi
+	echo "=== Running $# tests in ${GIT_TEST_INSTALLED:-this tree} ==="
+	for t in "$@"; do
+		./$t $GIT_TEST_OPTS
+	done
+}
+
+unpack_git_rev () {
+	rev=$1
+	echo "=== Unpacking $rev in build/$rev ==="
+	mkdir -p build/$rev
+	(cd "$(git rev-parse --show-cdup)" && git archive --format=tar $rev) |
+	(cd build/$rev && tar x)
+}
+
+build_git_rev () {
+	rev=$1
+	name="$2"
+	for config in config.mak config.mak.autogen config.status
+	do
+		if test -e "../../$config"
+		then
+			cp "../../$config" "build/$rev/"
+		fi
+	done
+	echo "=== Building $rev ($name) ==="
+	(
+		cd build/$rev &&
+		if test -n "$GIT_PERF_MAKE_COMMAND"
+		then
+			sh -c "$GIT_PERF_MAKE_COMMAND"
+		else
+			make $GIT_PERF_MAKE_OPTS
+		fi
+	) || die "failed to build revision '$mydir'"
+}
+
+set_git_test_installed () {
+	mydir=$1
+
+	mydir_abs=$(cd $mydir && pwd)
+	mydir_abs_wrappers="$mydir_abs_wrappers/bin-wrappers"
+	if test -d "$mydir_abs_wrappers"
+	then
+		GIT_TEST_INSTALLED=$mydir_abs_wrappers
+	else
+		# Older versions of git lacked bin-wrappers;
+		# fallback to the files in the root.
+		GIT_TEST_INSTALLED=$mydir_abs
+	fi
+	export GIT_TEST_INSTALLED
+	PERF_SET_GIT_TEST_INSTALLED=true
+	export PERF_SET_GIT_TEST_INSTALLED
+}
+
+run_dirs_helper () {
+	mydir=${1%/}
+	shift
+	while test $# -gt 0 -a "$1" != -- -a ! -f "$1"; do
+		shift
+	done
+	if test $# -gt 0 -a "$1" = --; then
+		shift
+	fi
+
+	PERF_RESULTS_PREFIX=
+	if test "$mydir" = "."
+	then
+		unset GIT_TEST_INSTALLED
+	elif test -d "$mydir"
+	then
+		PERF_RESULTS_PREFIX=bindir$(cd $mydir && printf "%s" "$(pwd)" | tr -c "[a-zA-Z0-9]" "_").
+		set_git_test_installed "$mydir"
+	else
+		rev=$(git rev-parse --verify "$mydir" 2>/dev/null) ||
+		die "'$mydir' is neither a directory nor a valid revision"
+		if [ ! -d build/$rev ]; then
+			unpack_git_rev $rev
+		fi
+		build_git_rev $rev "$mydir"
+		mydir=build/$rev
+
+		PERF_RESULTS_PREFIX=build_$rev.
+		set_git_test_installed "$mydir"
+	fi
+	export PERF_RESULTS_PREFIX
+
+	run_one_dir "$@"
+}
+
+run_dirs () {
+	while test $# -gt 0 -a "$1" != -- -a ! -f "$1"; do
+		run_dirs_helper "$@"
+		shift
+	done
+}
+
+get_subsections () {
+	section="$1"
+	test -z "$GIT_PERF_CONFIG_FILE" && return
+	git config -f "$GIT_PERF_CONFIG_FILE" --name-only --get-regex "$section\..*\.[^.]+" |
+	sed -e "s/$section\.\(.*\)\..*/\1/" | sort | uniq
+}
+
+get_var_from_env_or_config () {
+	env_var="$1"
+	conf_sec="$2"
+	conf_var="$3"
+	conf_opts="$4" # optional
+
+	# Do nothing if the env variable is already set
+	eval "test -z \"\${$env_var+x}\"" || return
+
+	test -z "$GIT_PERF_CONFIG_FILE" && return
+
+	# Check if the variable is in the config file
+	if test -n "$GIT_PERF_SUBSECTION"
+	then
+		var="$conf_sec.$GIT_PERF_SUBSECTION.$conf_var"
+		conf_value=$(git config $conf_opts -f "$GIT_PERF_CONFIG_FILE" "$var") &&
+		eval "$env_var=\"$conf_value\"" && return
+	fi
+	var="$conf_sec.$conf_var"
+	conf_value=$(git config $conf_opts -f "$GIT_PERF_CONFIG_FILE" "$var") &&
+	eval "$env_var=\"$conf_value\""
+}
+
+run_subsection () {
+	get_var_from_env_or_config "GIT_PERF_REPEAT_COUNT" "perf" "repeatCount" "--int"
+	: ${GIT_PERF_REPEAT_COUNT:=3}
+	export GIT_PERF_REPEAT_COUNT
+
+	get_var_from_env_or_config "GIT_PERF_DIRS_OR_REVS" "perf" "dirsOrRevs"
+	set -- $GIT_PERF_DIRS_OR_REVS "$@"
+
+	get_var_from_env_or_config "GIT_PERF_MAKE_COMMAND" "perf" "makeCommand"
+	get_var_from_env_or_config "GIT_PERF_MAKE_OPTS" "perf" "makeOpts"
+
+	get_var_from_env_or_config "GIT_PERF_REPO_NAME" "perf" "repoName"
+	export GIT_PERF_REPO_NAME
+
+	GIT_PERF_AGGREGATING_LATER=t
+	export GIT_PERF_AGGREGATING_LATER
+
+	if test $# = 0 -o "$1" = -- -o -f "$1"; then
+		set -- . "$@"
+	fi
+
+	codespeed_opt=
+	test "$GIT_PERF_CODESPEED_OUTPUT" = "true" && codespeed_opt="--codespeed"
+
+	run_dirs "$@"
+
+	if test -z "$GIT_PERF_SEND_TO_CODESPEED"
+	then
+		./aggregate.perl $codespeed_opt "$@"
+	else
+		json_res_file="test-results/$GIT_PERF_SUBSECTION/aggregate.json"
+		./aggregate.perl --codespeed "$@" | tee "$json_res_file"
+		send_data_url="$GIT_PERF_SEND_TO_CODESPEED/result/add/json/"
+		curl -v --request POST --data-urlencode "json=$(cat "$json_res_file")" "$send_data_url"
+	fi
+}
+
+get_var_from_env_or_config "GIT_PERF_CODESPEED_OUTPUT" "perf" "codespeedOutput" "--bool"
+get_var_from_env_or_config "GIT_PERF_SEND_TO_CODESPEED" "perf" "sendToCodespeed"
+
+cd "$(dirname $0)"
+. ../../GIT-BUILD-OPTIONS
+
+mkdir -p test-results
+get_subsections "perf" >test-results/run_subsections.names
+
+if test $(wc -l <test-results/run_subsections.names) -eq 0
+then
+	if test -n "$GIT_PERF_SUBSECTION"
+	then
+		if test -n "$GIT_PERF_CONFIG_FILE"
+		then
+			die "no subsections are defined in config file '$GIT_PERF_CONFIG_FILE'"
+		else
+			die "subsection '$GIT_PERF_SUBSECTION' defined without a config file"
+		fi
+	fi
+	(
+		run_subsection "$@"
+	)
+elif test -n "$GIT_PERF_SUBSECTION"
+then
+	egrep "^$GIT_PERF_SUBSECTION\$" test-results/run_subsections.names >/dev/null ||
+		die "subsection '$GIT_PERF_SUBSECTION' not found in '$GIT_PERF_CONFIG_FILE'"
+
+	egrep "^$GIT_PERF_SUBSECTION\$" test-results/run_subsections.names | while read -r subsec
+	do
+		(
+			GIT_PERF_SUBSECTION="$subsec"
+			export GIT_PERF_SUBSECTION
+			echo "======== Run for subsection '$GIT_PERF_SUBSECTION' ========"
+			run_subsection "$@"
+		)
+	done
+else
+	while read -r subsec
+	do
+		(
+			GIT_PERF_SUBSECTION="$subsec"
+			export GIT_PERF_SUBSECTION
+			echo "======== Run for subsection '$GIT_PERF_SUBSECTION' ========"
+			run_subsection "$@"
+		)
+	done <test-results/run_subsections.names
+fi