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grep 2.5.4 very slow with fixed pattern
From: |
Ethan Grammatikidis |
Subject: |
grep 2.5.4 very slow with fixed pattern |
Date: |
Thu, 11 Jun 2009 20:19:49 +0100 |
Hi, I just found grep being several orders of magnitude slower than Gnu sed for
doing the same task. I ran some timings, perhaps best if I just paste the
results. Grep is GNU grep 2.5.4, sed is GNU sed version 4.2, awk is GNU Awk
3.1.6. "9 grep" is plan9port grep, included for comparison.
$ wc -l deep-file-list
470485 deep-file-list
$ 9 grep ethan deep-file-list |wc -l
428065
$ time grep ethan deep-file-list > /dev/null
real 4m29.491s
user 4m29.366s
sys 0m0.080s
$ time grep -F ethan deep-file-list > /dev/null
real 4m27.740s
user 4m27.576s
sys 0m0.070s
$ time awk '/ethan/ {print}' deep-file-list > /dev/null
real 0m2.597s
user 0m2.570s
sys 0m0.017s
$ time sed -n /ethan/p deep-file-list > /dev/null
real 0m0.294s
user 0m0.273s
sys 0m0.020s
$ time 9 grep ethan deep-file-list > /dev/null
real 0m0.155s
user 0m0.140s
sys 0m0.017s
$
--
Ethan Grammatikidis
The lyf so short, the craft so long to lerne. -- Chaucer
- grep 2.5.4 very slow with fixed pattern,
Ethan Grammatikidis <=