From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268078AbUHXBxL (ORCPT ); Mon, 23 Aug 2004 21:53:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267464AbUHXBxJ (ORCPT ); Mon, 23 Aug 2004 21:53:09 -0400 Received: from mustang.oldcity.dca.net ([216.158.38.3]:39841 "HELO mustang.oldcity.dca.net") by vger.kernel.org with SMTP id S267425AbUHXBtV (ORCPT ); Mon, 23 Aug 2004 21:49:21 -0400 Subject: Re: [patch] voluntary-preempt-2.6.8.1-P8 From: Lee Revell To: Ingo Molnar Cc: linux-kernel In-Reply-To: <20040823210151.GA10949@elte.hu> References: <20040816040515.GA13665@elte.hu> <1092654819.5057.18.camel@localhost> <20040816113131.GA30527@elte.hu> <20040816120933.GA4211@elte.hu> <1092716644.876.1.camel@krustophenia.net> <20040817080512.GA1649@elte.hu> <20040819073247.GA1798@elte.hu> <20040820133031.GA13105@elte.hu> <20040820195540.GA31798@elte.hu> <20040821140501.GA4189@elte.hu> <20040823210151.GA10949@elte.hu> Content-Type: text/plain Message-Id: <1093312154.862.17.camel@krustophenia.net> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Mon, 23 Aug 2004 21:49:14 -0400 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2004-08-23 at 17:01, Ingo Molnar wrote: > - reduce netdev_max_backlog to 8 (Mark H Johnson) > On my system this setting has absolutely no effect on the skb related latencies. I tested setting netdev_max_backlog to every power of two between 1 and 128, and regardless of this setting, I can produce a 450-600 usec latency with: ping -s 65507 -f $DEFAULT_GATEWAY Looks like skb_checksum is the problem. Here is one of the traces: http://krustophenia.net/testresults.php?dataset=2.6.8.1-P8#/var/www/2.6.8.1-P8/trace14.txt Lee