From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?utf-8?B?SsO2cm4=?= Engel Subject: Re: [RFC 00/26] Slab defragmentation V5 Date: Thu, 6 Sep 2007 22:34:12 +0200 Message-ID: <20070906203412.GB27657@lazybastard.org> References: <20070901014107.719506437@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Andy Whitcroft , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig , Mel Gorman , David Chinner To: Christoph Lameter Return-path: Received: from lazybastard.de ([212.112.238.170]:43547 "EHLO longford.lazybastard.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756597AbXIFUiH (ORCPT ); Thu, 6 Sep 2007 16:38:07 -0400 Content-Disposition: inline In-Reply-To: <20070901014107.719506437@sgi.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Fri, 31 August 2007 18:41:07 -0700, Christoph Lameter wrote: >=20 > The trouble with this patchset is that it is difficult to validate. > Activities are only performed when special load situations are encoun= tered. > Are there any tests that could give meaningful information about > the effectiveness of these measures? I have run various tests here > creating and deleting files and building kernels under low memory sit= uations > to trigger these reclaim mechanisms but how does one measure their > effectiveness? One could play with updatedb followed by a memhog. How much time passe= s and how many slab objects have to be freed before the memhog has allocated N% of physical memory? Both numbers are relevant. The first indicates how quickly pages are reclaimed from slab caches, while the second show how many objects remain cached for future lookups. Updated= b aside, caching objects is done for solid performance reasons. Creating a qemu image with little memory and a huge directory hierarchy filled with 0-byte files may be a nice test system. Unless you beat me to it I'll try to set it up once logfs is in merge-worthy shape. J=C3=B6rn --=20 A quarrel is quickly settled when deserted by one party; there is no battle unless there be two. -- Seneca - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html