nix-super/corepkgs/config.nix.in
Eelco Dolstra 4911a10a4e 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.
2012-06-29 15:24:52 -04:00

14 lines
292 B
Nix

let
fromEnv = var: def:
let val = builtins.getEnv var; in
if val != "" then val else def;
in {
perl = "@perl@";
shell = "@shell@";
coreutils = "@coreutils@";
bzip2 = "@bzip2@";
xz = "@xz@";
tar = "@tar@";
tr = "@tr@";
nixBinDir = fromEnv "NIX_BIN_DIR" "@bindir@";
}