From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751425AbVKAXHt (ORCPT ); Tue, 1 Nov 2005 18:07:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751426AbVKAXHt (ORCPT ); Tue, 1 Nov 2005 18:07:49 -0500 Received: from amdext4.amd.com ([163.181.251.6]:20444 "EHLO amdext4.amd.com") by vger.kernel.org with ESMTP id S1751425AbVKAXHs (ORCPT ); Tue, 1 Nov 2005 18:07:48 -0500 X-Server-Uuid: 5FC0E2DF-CD44-48CD-883A-0ED95B391E89 Date: Tue, 1 Nov 2005 16:10:51 -0700 From: "Jordan Crouse" To: "Alan Cox" cc: linux-kernel@vger.kernel.org, info-linux@ldcmail.amd.com Subject: Re: AMD Geode GX/LX Support (Refreshed) Message-ID: <20051101231051.GM9947@cosmic.amd.com> References: <20051028154430.GB19854@cosmic.amd.com> <1130711970.32734.13.camel@localhost.localdomain> MIME-Version: 1.0 In-Reply-To: <1130711970.32734.13.camel@localhost.localdomain> User-Agent: Mutt/1.5.11 X-WSS-ID: 6F792AB622C4154630-01-01 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > config X86_USE_PPRO_CHECKSUM > Does this mean you've now done actual performance analysis on whether > this is a good idea for Geode GX/LX ? Ok - here is some data that should put your mind at ease. I pulled the checksum functions from the kernel, stuck them in userland, and ran each one N times at a variety of byte sizes (where N=10,000), took the start and stop times with gettimeofday(), and added it all up. The results for the Geode LX platfrom are below. I think the data shows that the ppro checksum is indeed useful on the Geode LX platform (and the GX should have similar results, since the pipelines are pretty close). Unless I made a really boneheaded mistake in my app, I think we should leave X86_USE_PPRO_CHECKSUM enabled for Geode GX/LX. Jordan Starting non-ppro test.... Bytes Time Avg (usec/run) ---------------------------- 16 2029 0.202900 32 1666 0.166600 64 2548 0.254800 128 3429 0.342900 256 5268 0.526800 512 8781 0.878100 1024 16031 1.603100 2048 30548 3.054800 4096 59265 5.926500 Total time: 129565 Starting ppro test.... Bytes Time Avg (usec/run) ---------------------------- 16 1579 0.157900 32 1655 0.165500 64 1841 0.184100 128 2721 0.272100 256 3582 0.358200 512 5264 0.526400 1024 8900 0.890000 2048 15919 1.591900 4096 29369 2.936900 Total time: 70830