Make grep 50x faster, 15.12.2013 14:33
Found this neat trick in Brendan Gregg's Blazing Performance with Flame Graphs talk.
Switching to LANG=C improved performance by 2000x
In a quick test I directly got a performance gain of factor 50.22.
This is quite an achievement for only changing one environment variable.
real:~# du -sh /var/log/querylog 148M /var/log/querylog real:~# time grep -i e /var/log/querylog > /dev/null real 0m12.807s user 0m12.437s sys 0m0.068s real:~# time LANG=C grep -i e /var/log/querylog > /dev/null real 0m0.255s user 0m0.196s sys 0m0.052s
I suspect that the performance gain may vary quite a lot depending on the search pattern. Also, please note that this trick only works when you know that the involved files and search patterns are ASCII only.
(via Standalone Sysadmin)