From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263134AbUB0WVv (ORCPT ); Fri, 27 Feb 2004 17:21:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263164AbUB0WVu (ORCPT ); Fri, 27 Feb 2004 17:21:50 -0500 Received: from fw.osdl.org ([65.172.181.6]:44948 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S263134AbUB0WVr (ORCPT ); Fri, 27 Feb 2004 17:21:47 -0500 Date: Fri, 27 Feb 2004 14:23:30 -0800 From: Andrew Morton To: "Martin J. Bligh" Cc: andrea@suse.de, riel@redhat.com, linux-kernel@vger.kernel.org Subject: Re: 2.4.23aa2 (bugfixes and important VM improvements for the high end) Message-Id: <20040227142330.4e72d9f4.akpm@osdl.org> In-Reply-To: <162060000.1077919387@flay> References: <20040227173250.GC8834@dualathlon.random> <20040227122936.4c1be1fd.akpm@osdl.org> <20040227211548.GI8834@dualathlon.random> <162060000.1077919387@flay> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i586-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org "Martin J. Bligh" wrote: > > > We can write a testcase ourself, it's pretty easy, just create a 2.7G > > file in /dev/shm, and mmap(MAP_SHARED) it from 1k processes and fault in > > all the pagetables from all tasks touching the shm vma. Then run a > > second copy until the machine starts swapping and see how thing goes. To > > do this you need probably 8G, this is why I didn't write the testcase > > myself yet ;). maybe I can simulate with less shm and less tasks on 1G > > boxes too, but the extreme lru effects of point 3 won't be visibile > > there, the very same software configuration works fine on 1/2G boxes on > > stock 2.4. problems showsup when the lru grows due the algorithm not > > contemplating million of dirty swapcache in a row at the end of the lru > > and some gigs of free cache ad the head of the lru. the rmap-only issues > > can also be tested with math, no testcase is needed for that. > > I don't have time at the moment to go write it at the moment, but I can certainly run it on large end hardware if that helps. I think just usemem -m 2700 -f test-file -r 10 -n 1000 will do it. I need to verify that. http://www.zip.com.au/~akpm/linux/patches/stuff/ext3-tools.tar.gz