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[grep] about 200 times slower than Sed or Perl
From: |
Eduard Bloch |
Subject: |
[grep] about 200 times slower than Sed or Perl |
Date: |
Tue, 9 Mar 2004 11:44:47 +0100 |
User-agent: |
Mutt/1.5.5.1+cvs20040105i |
Hello,
today I tried to weed out some useles lines from a large log file and
was amazed to see that the current grep versions (and fgrep) are
slow like hell.
debian:/# time fgrep -v MAC /var/log/kern.log | tail
...
real 0m25.092s
user 0m24.902s
sys 0m0.006s
debian:/# time perl -pe 'undef $_ if /MAC/' < /var/log/kern.log | tail
...
real 0m0.148s
user 0m0.065s
sys 0m0.007s
I don't think that this is a bug in POSIX regexp implementation, since
Sed is much faster (but still 7 times slower than Perl, lol):
debian:/# time sed -e 's/MAC/foobar/' < /var/log/kern.log | tail
...
real 0m0.747s
user 0m0.719s
sys 0m0.016s
debian:/# time perl -pe 's/MAC/foobar/' < /var/log/kern.log | tail
...
real 0m0.123s
user 0m0.090s
sys 0m0.016s
MfG,
Eduard.
- [grep] about 200 times slower than Sed or Perl,
Eduard Bloch <=