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| author | Eelco Dolstra <eelco.dolstra@logicblox.com> | 2012-06-29T18·26-0400 |
|---|---|---|
| committer | Eelco Dolstra <eelco.dolstra@logicblox.com> | 2012-06-29T19·24-0400 |
| commit | 4911a10a4e51102a21a5d123a852c75d2ec92dbc (patch) | |
| tree | 6e02ca6d92cc037efc89801960f4997a7d54e168 /corepkgs/nar.nix | |
| parent | 49cd7387ad6546571ca31a41f208091b482defaa (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 'corepkgs/nar.nix')
| -rw-r--r-- | corepkgs/nar.nix | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/corepkgs/nar.nix b/corepkgs/nar.nix index 4747dc31def2..c5155dcc917c 100644 --- a/corepkgs/nar.nix +++ b/corepkgs/nar.nix @@ -8,14 +8,15 @@ let echo "packing ‘$storePath’..." mkdir $out - dst=$out/tmp.nar.bz2 + dst=$out/tmp.nar.xz set -o pipefail - nix-store --dump "$storePath" | ${bzip2} > $dst + nix-store --dump "$storePath" | ${xz} -9 > $dst - nix-hash --flat --type $hashAlgo --base32 $dst > $out/narbz2-hash + hash=$(nix-hash --flat --type $hashAlgo --base32 $dst) + echo -n $hash > $out/nar-compressed-hash - mv $out/tmp.nar.bz2 $out/$(cat $out/narbz2-hash).nar.bz2 + mv $dst $out/$hash.nar.xz ''; in |