Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030494AbXBTWRX (ORCPT ); Tue, 20 Feb 2007 17:17:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030214AbXBTWRW (ORCPT ); Tue, 20 Feb 2007 17:17:22 -0500 Received: from outpost.ds9a.nl ([213.244.168.210]:39938 "EHLO outpost.ds9a.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030193AbXBTWRV (ORCPT ); Tue, 20 Feb 2007 17:17:21 -0500 Date: Tue, 20 Feb 2007 23:17:20 +0100 From: bert hubert To: Rick Jones Cc: Evgeniy Polyakov , Josef Sipek , Andi Kleen , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: all syscalls initially taking 4usec on a P4? Re: nonblocking UDPv4 recvfrom() taking 4usec @ 3GHz? Message-ID: <20070220221719.GA16263@outpost.ds9a.nl> Mail-Followup-To: bert hubert , Rick Jones , Evgeniy Polyakov , Josef Sipek , Andi Kleen , netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20070219231447.GA4400@outpost.ds9a.nl> <20070220162714.GA3245@outpost.ds9a.nl> <20070220164124.GA24930@2ka.mipt.ru> <20070220184242.GA30077@filer.fsl.cs.sunysb.edu> <20070220184859.GA1949@2ka.mipt.ru> <20070220193319.GA8800@outpost.ds9a.nl> <45DB6FD8.4050106@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45DB6FD8.4050106@hp.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1273 Lines: 31 On Tue, Feb 20, 2007 at 02:02:00PM -0800, Rick Jones wrote: > The slope appears to be flattening-out the farther out to the right it > goes. Perhaps that is the length of time it takes to take all the > requisite cache misses. The rate of flattening out appears to correlate with the number of processes running, even though the system is otherwise >99.5% idle during my measurements. With only 'gdm' running, things flatten out slowly, iow, it takes longer delays to see recvfrom slow down. With only 1 process running (init=bash), the graph is nearly flat. >From this, it is probable that even an idle GNOME desktop (Ubunty Edgy Eft) is under fierce cache pressure, enough to blow away my meagre 1MB in a matter of milliseconds. I'm trying to figure out which processes have the most impact, I had already killed anything non-essential. But that still leaves 140 pids. Bert -- http://www.PowerDNS.com Open source, database driven DNS Software http://netherlabs.nl Open and Closed source services - 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/