Re: Bug#439931: grep: Enormous slowdown on AMD64

[Justin Pryzby]

tag 439827 upstream
forwarded 439827 address@hidden
thanks

This performance regression was reported for the new grep upload.

On Tue, Aug 28, 2007 at 04:51:07PM +0200, Gabor Gombas wrote:
> Package: grep
> Version: 2.5.3~dfsg-1
> Severity: important
> 
> 
> Hi,
> 
> After upgrading grep to 2.5.3~dfsg-1:
> 
> $ time grep '^foo b' bar >/dev/null
> 
> real    0m34.745s
> user    0m34.522s
> sys     0m0.032s
> 
> While in a 32-bit chroot on the same machine, same package version, same
> input file:
> 
> $ time grep '^foo b' bar >/dev/null
> 
> real    0m0.123s
> user    0m0.120s
> sys     0m0.000s
> 
> Both cases are cache-hot representative values of multiple measurements.
> The file searched is a ~30 MiB textfile. Up until yesterday the 64-bit
> version was a little faster... IMHO this nearly 300x slowdown makes 'grep'
> practically unusable for any serious work on AMD64.
> 
> Gabor
> 
> -- System Information:
> Debian Release: lenny/sid
>   APT prefers unstable
>   APT policy: (990, 'unstable'), (500, 'stable'), (101, 'experimental')
> Architecture: amd64 (x86_64)
> 
> Kernel: Linux 2.6.22.1
> Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
> Shell: /bin/sh linked to /bin/dash
> 
> Versions of packages grep depends on:
> ii  libc6                         2.6.1-1    GNU C Library: Shared libraries