0000758: grep extremely slow - BusyBox Bug and Patch Tracking

BusyBox Bug and Patch Tracking

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Category

Severity

Reproducibility

Date Submitted

Last Update

0000758

[BusyBox] Other

major

always

02-28-06 00:24

03-09-06 14:25

Reporter

rfelker

View Status

public

Assigned To

BusyBox

Priority

normal

Resolution

fixed

Status

closed

Product Version

Summary

0000758: grep extremely slow

Description

time ./busybox grep a.*b ~/Mail/saved > /dev/null
real 0m19.583s
user 0m19.337s
sys 0m0.097s

time grep a.*b ~/Mail/saved > /dev/null
real 0m0.379s
user 0m0.283s
sys 0m0.083s

This is because the busybox version insists on recompiling the regex over and over on each line. Fixing it is a matter of just calling regcomp once and keeping the regex. It's trivial for the case of only one pattern, but requires a tradeoff between memory and performance for the case of many patterns.

Additional Information

My comparison isn't quit fair since the two times are with different regex implementations. However the current grep code is still obviously wrong.

Attached Files

Relationships

Notes
(0001146) vodz 02-28-06 02:11	Ok. See 14361 SVN revision.

Issue History
Date Modified	Username	Field	Change
02-28-06 00:24	rfelker	New Issue
02-28-06 00:24	rfelker	Status	new => assigned
02-28-06 00:24	rfelker	Assigned To	=> BusyBox
02-28-06 02:11	vodz	Note Added: 0001146
02-28-06 02:11	vodz	Status	assigned => resolved
02-28-06 02:11	vodz	Resolution	open => fixed
03-09-06 14:25	landley	Status	resolved => closed