Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269581AbUI3WBb (ORCPT ); Thu, 30 Sep 2004 18:01:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269535AbUI3WBb (ORCPT ); Thu, 30 Sep 2004 18:01:31 -0400 Received: from fw.osdl.org ([65.172.181.6]:46782 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S269582AbUI3WAu (ORCPT ); Thu, 30 Sep 2004 18:00:50 -0400 Date: Thu, 30 Sep 2004 15:00:46 -0700 (PDT) From: Judith Lebzelter To: William Lee Irwin III cc: Judith Lebzelter , , , Subject: Re: OSDL aio-stress results on latest kernels show buffered random read issue In-Reply-To: <20040930004447.GI9106@holomorphy.com> Message-ID: 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: 1134 Lines: 36 On Wed, 29 Sep 2004, William Lee Irwin III wrote: > On Wed, Sep 29, 2004 at 04:29:08PM -0700, Judith Lebzelter wrote: > > There seems to be an issue with the reads. Usually, reads > > should be at least as fast as writes of the same type. > > Also, there seems to be a substantial drop-off in the performance > > of AIO buffered-random writes in the mm kernels. (14% on 2CPU, > > 40% on 4CPU) > > Okay, is it cpu time or idle/iowait? If it's cpu time, where do > profiles show it appears? Th CPU is not that busy: 2.6.9-rc2-mm4 Results and iostat outputs: http://khack.osdl.org/stp/297714/ http://khack.osdl.org/stp/297714/results/bufferrand/iostat.txt 2.6.9-rc2 Results and iostat outputs: http://khack.osdl.org/stp/297545/ http://khack.osdl.org/stp/297545/results/bufferrand/iostat.txt The iostat has the write stats followed by the reads, taken every 15 seconds. > > > -- wli > - 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/