linux-kernel - Re: [PATCH] x86: generic versions of find_first_(zero

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Message-ID: <20080407084351.GD3707@elte.hu>
Date:	Mon, 7 Apr 2008 10:43:51 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	dean gaudet <dean@...tic.org>
Cc:	Alexander van Heukelum <heukelum@...tmail.fm>,
	Alexander van Heukelum <heukelum@...lshack.com>,
	Andi Kleen <andi@...stfloor.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: generic versions of find_first_(zero_)bit,
	convert i386


* dean gaudet <dean@...tic.org> wrote:

> On Sun, 6 Apr 2008, Alexander van Heukelum wrote:
> 
> > The current generic implementation of ffz is O(lg(n)) already
> 
> it's O(lg(n)) time... the operations all depend on each other.
> 
> the implementation i pointed to is O(lg(n)) code space... and the time 
> depends on how parallel the machine is, they're not dependent on each 
> other.

yep, i'd suggest we gravitate towards such a no-dependencies 
implementation for the generic code - especially modern CPUs would be 
able to execute them rather efficiently.

	Ingo
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