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authorEelco Dolstra <eelco.dolstra@logicblox.com>2012-08-13T03·29-0400
committerEelco Dolstra <eelco.dolstra@logicblox.com>2012-08-13T03·29-0400
commite82767910c649f160d6701e47f606f3b8dde4b29 (patch)
treea951e469b37adfe3db1485a0bc8996ac4cc51416 /src/libutil
parent325d1cfebf6c8ad391dc318f984feb3e5731aa5a (diff)
Add some basic profiling support to the evaluator
Setting the environment variable NIX_COUNT_CALLS to 1 enables some
basic profiling in the evaluator.  It will count calls to functions
and primops as well as evaluations of attributes.

For example, to see where evaluation of a NixOS configuration spends
its time:

$ NIX_SHOW_STATS=1 NIX_COUNT_CALLS=1 ./src/nix-instantiate/nix-instantiate '<nixos>' -A system --readonly-mode
...
calls to 39 primops:
    239532 head
    233962 tail
    191252 hasAttr
...
calls to 1595 functions:
    224157 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/lists.nix:17:19'
    221767 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/lists.nix:17:14'
    221767 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/lists.nix:17:10'
...
evaluations of 7088 attributes:
    167377 undefined position
    132459 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/attrsets.nix:119:41'
     47322 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/attrsets.nix:13:21'
...
Diffstat (limited to 'src/libutil')
-rw-r--r--src/libutil/util.hh3
1 files changed, 3 insertions, 0 deletions
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index edb7c0fa6c60..dc38a53ca2fe 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -17,6 +17,9 @@ namespace nix {
 #define foreach(it_type, it, collection)                                \
     for (it_type it = (collection).begin(); it != (collection).end(); ++it)
 
+#define foreach_reverse(it_type, it, collection)                                \
+    for (it_type it = (collection).rbegin(); it != (collection).rend(); ++it)
+
 
 /* Return an environment variable. */
 string getEnv(const string & key, const string & def = "");