Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 23 Aug 2002 10:41:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 23 Aug 2002 10:41:48 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.102]:48801 "EHLO e2.ny.us.ibm.com") by vger.kernel.org with ESMTP id ; Fri, 23 Aug 2002 10:41:45 -0400 Subject: Re: [Lse-tech] Re: (RFC): SKB Initialization To: haveblue@us.ibm.com Cc: Benjamin LaHaise , alan@lxorguk.ukuu.org.uk, "Bill Hartner" , davem@redhat.com, linux-kernel@vger.kernel.org, lse-tech@lists.sourceforge.net, lse-tech-admin@lists.sourceforge.net X-Mailer: Lotus Notes Release 5.0.7 March 21, 2001 Message-ID: From: "Mala Anand" Date: Fri, 23 Aug 2002 09:44:23 -0500 X-MIMETrack: Serialize by Router on D03NM123/03/M/IBM(Release 5.0.10 |March 22, 2002) at 08/23/2002 08:44:26 AM MIME-Version: 1.0 Content-type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1691 Lines: 54 Dave Hansen wrote.. >Mala Anand wrote: >> The third scope would be measuring this patch in a workload environment. >> We measured it in a web serving workload and found that we get 0.7% >> improvement. >First of all, the patch doesn't apply at all against the current >bitkeeper tree. I can post the exact one I used if you like. >I tried this under our Specweb99 setup. Here's a snippet of >readprofile with, then without the patch: >alloc:free ratio: 1.226 >(__kfree_skb+alloc_skb)/total = 3.14% >alloc:free ratio: 0.348 >(__kfree_skb+alloc_skb)/total = 2.79% >You can see the entire readprofile here: >http://www.sr71.net/~specweb99/run-specweb-100sec-2400-2.5.31-bk+4-kmap-08-22-2002-11.20.17/ >http://www.sr71.net/~specweb99/run-specweb-100sec-2400-2.5.31-bk+4-kmap-mala-08-22-2002-11.44.25/ >No, I don't know why I have so much idle time. Readprofile ticks are not as accurate as the cycles I measured. Moreover readprofile can give misleading information as it profiles on timer interrupts. The alloc_skb and __kfree_skb call memory management routines and interrupts are disabled in many parts of that code. So I don't trust the readprofile data. Regards, Mala Mala Anand IBM Linux Technology Center - Kernel Performance E-mail:manand@us.ibm.com http://www-124.ibm.com/developerworks/opensource/linuxperf http://www-124.ibm.com/developerworks/projects/linuxperf Phone:838-8088; Tie-line:678-8088 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/