linux-kernel - Re: [PATCH] x86: Change x86 to use generic find_next

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Message-ID: <87myp7zire.fsf@basil.nowhere.org>
Date:	09 Mar 2008 22:31:49 +0100
From:	Andi Kleen <andi@...stfloor.org>
To:	Alexander van Heukelum <heukelum@...lshack.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.com>,
	LKML <linux-kernel@...r.kernel.org>, heukelum@...tmail.fm
Subject: Re: [PATCH] x86: Change x86 to use generic find_next_bit

Alexander van Heukelum <heukelum@...lshack.com> writes:
> 
> Benchmark using: gcc -fomit-frame-pointer -Os. For each bitmap size 
> 1...512, for each possible bitmap with one bit set, for each possible 
> offset: find the position of the first bit starting at offset. If you 
> follow ;). Times include setup of the bitmap and checking of the 
> results.

BTW another comment: it would be far more sense if you did 
some profiling on what bitmap sizes a real kernel uses
(should be easy enough with some systemtap) and benchmarked
only that.

I doubt 1 bit bitmap searches are common for example ...

-Andi
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