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From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: Alan Cox <alc@cs.rice.edu>
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Date: Fri, 20 Aug 2010 21:27:44 +0200
In-Reply-To: <4C6D5302.4030602@cs.rice.edu> (Alan Cox's message of "Thu, 19
	Aug 2010 10:51:30 -0500")
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Cc: alc@freebsd.org, Dimitry Andric <dimitry@andric.com>, current@freebsd.org
Subject: Re: Official request: Please make GNU grep the default
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Alan Cox <alc@cs.rice.edu> writes:
> Here is what actually puzzles me about these results.  With
> traditional I/O, even after the optimizations to bsdgrep, the system
> time for gnugrep is still less than half that of the optimized
> bsdgrep.  I haven't looked at the changes, but I would have thought
> the system time for gnugrep and bsdgrep would be almost the same.

Two reasons:

1) BSD grep does tons of unnecessary memory-to-memory copy operations in
   grep_fgetln().

2) GNU grep has its own highly optimized regex code.

DES
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Dag-Erling Sm=C3=B8rgrav - des@des.no