Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965234AbXAJXTI (ORCPT ); Wed, 10 Jan 2007 18:19:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965237AbXAJXTH (ORCPT ); Wed, 10 Jan 2007 18:19:07 -0500 Received: from omx2-ext.sgi.com ([192.48.171.19]:36786 "EHLO omx2.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S965234AbXAJXTG (ORCPT ); Wed, 10 Jan 2007 18:19:06 -0500 Date: Thu, 11 Jan 2007 10:18:48 +1100 From: David Chinner To: Christoph Lameter Cc: David Chinner , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [REGRESSION] 2.6.19/2.6.20-rc3 buffered write slowdown Message-ID: <20070110231848.GS33919298@melbourne.sgi.com> References: <20070110223731.GC44411608@melbourne.sgi.com> <20070110230855.GF44411608@melbourne.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1165 Lines: 32 On Wed, Jan 10, 2007 at 03:12:02PM -0800, Christoph Lameter wrote: > On Thu, 11 Jan 2007, David Chinner wrote: > > > Well, pdflush appears to be doing very little on both 2.6.18 and > > 2.6.20-rc3. In both cases kswapd is consuming 10-20% of a CPU and > > all of the pdflush threads combined (I've seen up to 7 active at > > once) use maybe 1-2% of cpu time. This occurs regardless of the > > dirty_ratio setting. > > That sounds a bit much for kswapd. How many nodes? Any cpusets in use? It's an x86-64 box - an XE 240 - 4 core, 16GB RAM, single node, no cpusets. > A upper maximum on the number of pdflush threads exists at 8. Are these > multiple files or single file transfers? See the test case i posted - a single file write per filesystem, three filesystems being written to at once, all on different, unshared block devices. Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group - 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/