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From: Andi Kleen <andi@firstfloor.org>
To: Alexander van Heukelum <heukelum@mailshack.com>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
	"H. Peter Anvin" <hpa@zytor.com>,
	LKML <linux-kernel@vger.kernel.org>,
	heukelum@fastmail.fm
Subject: Re: [PATCH] x86: Change x86 to use generic find_next_bit
Date: 09 Mar 2008 22:31:49 +0100	[thread overview]
Message-ID: <87myp7zire.fsf@basil.nowhere.org> (raw)
In-Reply-To: <20080309200103.GA895@mailshack.com>

Alexander van Heukelum <heukelum@mailshack.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

  parent reply	other threads:[~2008-03-09 21:32 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-09 20:01 [PATCH] x86: Change x86 to use generic find_next_bit Alexander van Heukelum
2008-03-09 20:10 ` Ingo Molnar
2008-03-09 21:03   ` Andi Kleen
2008-03-09 21:32     ` Andi Kleen
2008-03-09 21:13   ` Alexander van Heukelum
2008-03-10  6:29     ` Ingo Molnar
2008-03-09 20:11 ` Ingo Molnar
2008-03-09 20:31   ` Alexander van Heukelum
2008-03-09 20:51     ` Ingo Molnar
2008-03-09 21:29       ` Andi Kleen
2008-03-10 23:17       ` [RFC/PATCH] x86: Optimize find_next_(zero_)bit for small constant-size bitmaps Alexander van Heukelum
2008-03-11  9:56         ` Ingo Molnar
2008-03-11 15:17           ` [PATCH] " Alexander van Heukelum
2008-03-11 15:22             ` [RFC] non-x86: " Alexander van Heukelum
2008-03-11 15:23             ` [PATCH] x86: " Ingo Molnar
2008-03-09 20:28 ` [PATCH] x86: Change x86 to use generic find_next_bit Andi Kleen
2008-03-09 21:31 ` Andi Kleen [this message]
2008-03-13 12:44 ` Aneesh Kumar K.V
2008-03-13 14:27   ` Alexander van Heukelum

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