Date: Fri, 2 May 2003 02:10:50 +0200
From: Willy Tarreau <willy@w.ods.org>
To: Thomas Schlichter <schlicht@uni-mannheim.de>
Cc: Willy TARREAU <willy@w.ods.org>, hugang <hugang@soulinfo.com>,
       linux-kernel@vger.kernel.org, akpm@digeo.com, dphillips@sistina.com
Subject: Re: [RFC][PATCH] Faster generic_fls
Message-ID: <20030502001050.GA25789@alpha.home.local>
References: <200304300446.24330.dphillips@sistina.com> <20030501225321.6b30e8dc.hugang@soulinfo.com> <20030501171627.GA1785@pcw.home.local> <200305020127.26279.schlicht@uni-mannheim.de>
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On Fri, May 02, 2003 at 01:27:16AM +0200, Thomas Schlichter wrote:
 
> So for me the table version seems to be the slowest one. The BSRL instruction 
> on the K6-III seems to be very slow, too. The tree and my shift version are 
> faster than the original version here...
> 
> That someone else can test my fls_shift version I'll provide it here again:

That's interesting Thomasr. I get 18.4 s on the Athlon here vs 32.3 for Daniel's
(I have broken my function at the moment so I cannot re-bench it right now, but
it should be near Daniel's). At first, I thought you had coded an FFS instead of
an FLS. But I realized it's valid, and is fast because one half of the numbers
tested will not even take one iteration.

Regards,
Willy

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