[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
bug#17700: [PATCH] dfa: speed-up for a pattern that many atoms are caten
bug#17700: [PATCH] dfa: speed-up for a pattern that many atoms are catenated
Fri, 06 Jun 2014 07:49:22 +0900
Paul Eggert wrote:
> It seems to me that much of the performance benefit comes from using a
> faster implementation of strstr, and that the DFA code will be better
> off if it simply uses the system strstr rather than rolling its own.
`lookfor' isn't terminated by `\-'\0' in istrstr(), but strstr() requires
it. So I wasn't replace it to strstr();
after `grep: undo part of previous change', no longer faster.
$ printf '%02048d\n' 0 | time -p src/grep -f - /dev/null
master : real 5.74 user 5.40 sys 0.17
my patch: real 0.08 user 0.04 sys 0.04