I recently noticed CentOS 5.3′s
sort is way slower than Ubuntu 9.04′s. Apparently the i18n patch used in coreutils-5.97 CentOS rpm is a performance killer:
$ LANG=C time -p sort --buffer-size=128M -n -k1 -k2 test.info > /dev/null real 92.58 user 86.04 sys 6.52 $ time -p sort --buffer-size=128M -n -k1 -k2 test.info > /dev/null real 463.04 user 456.01 sys 6.64
grep and other locale sensitive utilities have similar issue.
BTW, if your disk is slow,
--buffer-size is a parameter you might want to play with to optimize performance. By default
sort uses very conservative buffer size while your seemingly used memory is actually just used for cache. [ref]