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authorEelco Dolstra <eelco.dolstra@logicblox.com>2012-06-29T18·26-0400
committerEelco Dolstra <eelco.dolstra@logicblox.com>2012-06-29T19·24-0400
commit4911a10a4e51102a21a5d123a852c75d2ec92dbc (patch)
tree6e02ca6d92cc037efc89801960f4997a7d54e168 /perl/lib/Nix/Config.pm.in
parent49cd7387ad6546571ca31a41f208091b482defaa (diff)
Use XZ compression in binary caches
XZ compresses significantly better than bzip2.  Here are the
compression ratios and execution times (using 4 cores in parallel) on
my /var/run/current-system (3.1 GiB):

  bzip2: total compressed size 849.56 MiB, 30.8% [2m08]
  xz -6: total compressed size 641.84 MiB, 23.4% [6m53]
  xz -7: total compressed size 621.82 MiB, 22.6% [7m19]
  xz -8: total compressed size 599.33 MiB, 21.8% [7m18]
  xz -9: total compressed size 588.18 MiB, 21.4% [7m40]

Note that compression takes much longer.  More importantly, however,
decompression is much faster:

  bzip2: 1m47.274s
  xz -6: 0m55.446s
  xz -7: 0m54.119s
  xz -8: 0m52.388s
  xz -9: 0m51.842s

The only downside to using -9 is that decompression takes a fair
amount (~65 MB) of memory.
Diffstat (limited to 'perl/lib/Nix/Config.pm.in')
-rw-r--r--perl/lib/Nix/Config.pm.in3
1 files changed, 2 insertions, 1 deletions
diff --git a/perl/lib/Nix/Config.pm.in b/perl/lib/Nix/Config.pm.in
index b6d346651807..5adc1ffba9e9 100644
--- a/perl/lib/Nix/Config.pm.in
+++ b/perl/lib/Nix/Config.pm.in
@@ -7,7 +7,8 @@ $manifestDir = $ENV{"NIX_MANIFESTS_DIR"} || "@localstatedir@/nix/manifests";
 $logDir = $ENV{"NIX_LOG_DIR"} || "@localstatedir@/log/nix";
 $confDir = $ENV{"NIX_CONF_DIR"} || "@sysconfdir@/nix";
 
-$bzip2 = $ENV{"NIX_BZIP2"} || "@bzip2@";
+$bzip2 = "@bzip2@";
+$xz = "@xz@";
 $curl = "@curl@";
 
 $useBindings = "@perlbindings@" eq "yes";