* Sami Liedes <slie...@cc.hut.fi>, 2011-07-02, 14:39:
I believe merely using lzop could give a 2-4x speedup:
------------------------------------------------------------
$ time gzip -d <ftp.fi.debian.org_debian_dists_unstable_Contents-amd64.gz
>/dev/null
real 0m1.608s
user 0m1.584s
sys 0m0.016s
$ time lzop -d <ftp.fi.debian.org_debian_dists_unstable_Contents-amd64.lzo
>/dev/null
real 0m0.382s
user 0m0.356s
sys 0m0.024s
------------------------------------------------------------
You could achieve further speedup by using the -F option:
$ time gzip -dc < dists/unstable/main/Contents-amd64.gz > /dev/null
real 0m2.197s
user 0m2.184s
sys 0m0.012s
$ time lzop -dc < dists/unstable/main/Contents-amd64.lzo > /dev/null
real 0m0.475s
user 0m0.448s
sys 0m0.028s
$ time lzop -dFc < dists/unstable/main/Contents-amd64.lzo > /dev/null
real 0m0.266s
user 0m0.232s
sys 0m0.032s
That's only twice slower than reading uncompressed file:
$ time cat dists/unstable/main/Contents-amd64 > /dev/null
real 0m0.130s
user 0m0.000s
sys 0m0.128s
However, that's only because the files are already cached. If I drop
caches before running the commands, lzop wins:
$ time cat dists/unstable/main/Contents-amd64 > /dev/null
real 0m1.495s
user 0m0.000s
sys 0m0.224s
$ time lzop -dFc < dists/unstable/main/Contents-amd64.lzo > /dev/null
real 0m0.370s
user 0m0.264s
sys 0m0.020s
--
Jakub Wilk
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