From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Date: Thu, 09 Dec 2004 08:00:10 +0000 Subject: Re: page fault scalability patch V12 [0/7]: Overview and performance Message-Id: <41B8060A.4050402@yahoo.com.au> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Christoph Lameter Cc: Linus Torvalds , Hugh Dickins , akpm@osdl.org, Benjamin Herrenschmidt , linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org Christoph Lameter wrote: > Changes from V11->V12 of this patch: > - dump sloppy_rss in favor of list_rss (Linus' proposal) > - keep up against current Linus tree (patch is based on 2.6.10-rc2-bk14) > [snip] > For more than 8 cpus the page fault rate increases by orders > of magnitude. For more than 64 cpus the improvement in performace > is 10 times better. Those numbers are pretty impressive. I thought you'd said with earlier patches that performance was about doubled from 8 to 512 CPUS. Did I remember correctly? If so, where is the improvement coming from? The per-thread RSS I guess? On another note, these patches are basically only helpful to new anonymous page faults. I guess this is the main thing you are concerned about at the moment, but I wonder if you would see improvements with my patch to remove the ptl from the other types of faults as well? The downside of my patch - well the main downsides - compared to yours are its intrusiveness, and the extra cost involved in copy_page_range which yours appears not to require. As I've said earlier though, I wouldn't mind your patches going in. At least they should probably get into -mm soon, when Andrew has time (and after the 4level patches are sorted out). That wouldn't stop my patch (possibly) being merged some time after that if and when it was found worthy... From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261484AbULIIA2 (ORCPT ); Thu, 9 Dec 2004 03:00:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261492AbULIIA1 (ORCPT ); Thu, 9 Dec 2004 03:00:27 -0500 Received: from smtp201.mail.sc5.yahoo.com ([216.136.129.91]:54629 "HELO smtp201.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S261484AbULIIAS (ORCPT ); Thu, 9 Dec 2004 03:00:18 -0500 Message-ID: <41B8060A.4050402@yahoo.com.au> Date: Thu, 09 Dec 2004 19:00:10 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.3) Gecko/20041007 Debian/1.7.3-5 X-Accept-Language: en MIME-Version: 1.0 To: Christoph Lameter CC: Linus Torvalds , Hugh Dickins , akpm@osdl.org, Benjamin Herrenschmidt , linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: page fault scalability patch V12 [0/7]: Overview and performance tests References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Christoph Lameter wrote: > Changes from V11->V12 of this patch: > - dump sloppy_rss in favor of list_rss (Linus' proposal) > - keep up against current Linus tree (patch is based on 2.6.10-rc2-bk14) > [snip] > For more than 8 cpus the page fault rate increases by orders > of magnitude. For more than 64 cpus the improvement in performace > is 10 times better. Those numbers are pretty impressive. I thought you'd said with earlier patches that performance was about doubled from 8 to 512 CPUS. Did I remember correctly? If so, where is the improvement coming from? The per-thread RSS I guess? On another note, these patches are basically only helpful to new anonymous page faults. I guess this is the main thing you are concerned about at the moment, but I wonder if you would see improvements with my patch to remove the ptl from the other types of faults as well? The downside of my patch - well the main downsides - compared to yours are its intrusiveness, and the extra cost involved in copy_page_range which yours appears not to require. As I've said earlier though, I wouldn't mind your patches going in. At least they should probably get into -mm soon, when Andrew has time (and after the 4level patches are sorted out). That wouldn't stop my patch (possibly) being merged some time after that if and when it was found worthy... From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <41B8060A.4050402@yahoo.com.au> Date: Thu, 09 Dec 2004 19:00:10 +1100 From: Nick Piggin MIME-Version: 1.0 Subject: Re: page fault scalability patch V12 [0/7]: Overview and performance tests References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Linus Torvalds , Hugh Dickins , akpm@osdl.org, Benjamin Herrenschmidt , linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org List-ID: Christoph Lameter wrote: > Changes from V11->V12 of this patch: > - dump sloppy_rss in favor of list_rss (Linus' proposal) > - keep up against current Linus tree (patch is based on 2.6.10-rc2-bk14) > [snip] > For more than 8 cpus the page fault rate increases by orders > of magnitude. For more than 64 cpus the improvement in performace > is 10 times better. Those numbers are pretty impressive. I thought you'd said with earlier patches that performance was about doubled from 8 to 512 CPUS. Did I remember correctly? If so, where is the improvement coming from? The per-thread RSS I guess? On another note, these patches are basically only helpful to new anonymous page faults. I guess this is the main thing you are concerned about at the moment, but I wonder if you would see improvements with my patch to remove the ptl from the other types of faults as well? The downside of my patch - well the main downsides - compared to yours are its intrusiveness, and the extra cost involved in copy_page_range which yours appears not to require. As I've said earlier though, I wouldn't mind your patches going in. At least they should probably get into -mm soon, when Andrew has time (and after the 4level patches are sorted out). That wouldn't stop my patch (possibly) being merged some time after that if and when it was found worthy... -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org