Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757773Ab3JOHl3 (ORCPT ); Tue, 15 Oct 2013 03:41:29 -0400 Received: from mail-ee0-f49.google.com ([74.125.83.49]:41810 "EHLO mail-ee0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757210Ab3JOHl1 (ORCPT ); Tue, 15 Oct 2013 03:41:27 -0400 Date: Tue, 15 Oct 2013 09:41:23 +0200 From: Ingo Molnar To: Joe Perches Cc: Eric Dumazet , Neil Horman , linux-kernel@vger.kernel.org, sebastien.dugue@bull.net, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org Subject: Re: [PATCH] x86: Run checksumming in parallel accross multiple alu's Message-ID: <20131015074123.GB25493@gmail.com> References: <1381510298-20572-1-git-send-email-nhorman@tuxdriver.com> <20131012172124.GA18241@gmail.com> <20131014202854.GH26880@hmsreliant.think-freely.org> <1381785560.2045.11.camel@edumazet-glaptop.roam.corp.google.com> <1381789127.2045.22.camel@edumazet-glaptop.roam.corp.google.com> <1381790278.16896.2.camel@joe-AO722> <1381790686.2045.24.camel@edumazet-glaptop.roam.corp.google.com> <1381790982.16896.7.camel@joe-AO722> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1381790982.16896.7.camel@joe-AO722> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1941 Lines: 51 * Joe Perches wrote: > On Mon, 2013-10-14 at 15:44 -0700, Eric Dumazet wrote: > > On Mon, 2013-10-14 at 15:37 -0700, Joe Perches wrote: > > > On Mon, 2013-10-14 at 15:18 -0700, Eric Dumazet wrote: > > > > attached patch brings much better results > > > > > > > > lpq83:~# ./netperf -H 7.7.8.84 -l 10 -Cc > > > > MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.8.84 () port 0 AF_INET > > > > Recv Send Send Utilization Service Demand > > > > Socket Socket Message Elapsed Send Recv Send Recv > > > > Size Size Size Time Throughput local remote local remote > > > > bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB > > > > > > > > 87380 16384 16384 10.00 8043.82 2.32 5.34 0.566 1.304 > > > > > > > > diff --git a/arch/x86/lib/csum-partial_64.c b/arch/x86/lib/csum-partial_64.c > > > [] > > > > @@ -68,7 +68,8 @@ static unsigned do_csum(const unsigned char *buff, unsigned len) > > > > zero = 0; > > > > count64 = count >> 3; > > > > while (count64) { > > > > - asm("addq 0*8(%[src]),%[res]\n\t" > > > > + asm("prefetch 5*64(%[src])\n\t" > > > > > > Might the prefetch size be too big here? > > > > To be effective, you need to prefetch well ahead of time. > > No doubt. So why did you ask then? > > 5*64 seems common practice (check arch/x86/lib/copy_page_64.S) > > 5 cachelines for some processors seems like a lot. What processors would that be? Most processors have hundreds of cachelines even in their L1 cache. Thousands in the L2 cache, up to hundreds of thousands. Thanks, Ingo -- 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/