From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946098AbXDEIcg (ORCPT ); Thu, 5 Apr 2007 04:32:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1946099AbXDEIcg (ORCPT ); Thu, 5 Apr 2007 04:32:36 -0400 Received: from mx1.redhat.com ([66.187.233.31]:47295 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946098AbXDEIce (ORCPT ); Thu, 5 Apr 2007 04:32:34 -0400 Message-ID: <4614B3FB.2090405@redhat.com> Date: Thu, 05 Apr 2007 04:31:55 -0400 From: Rik van Riel Organization: Red Hat, Inc User-Agent: Thunderbird 1.5.0.7 (X11/20061008) MIME-Version: 1.0 To: Eric Dumazet CC: Jakub Jelinek , Ulrich Drepper , Andrew Morton , Andi Kleen , Linux Kernel , linux-mm@kvack.org, Hugh Dickins Subject: Re: missing madvise functionality References: <46128051.9000609@redhat.com> <46128CC2.9090809@redhat.com> <20070403172841.GB23689@one.firstfloor.org> <20070403125903.3e8577f4.akpm@linux-foundation.org> <4612B645.7030902@redhat.com> <20070403202937.GE355@devserv.devel.redhat.com> <4614A5CC.5080508@redhat.com> <20070405100848.db97d835.dada1@cosmosbay.com> In-Reply-To: <20070405100848.db97d835.dada1@cosmosbay.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Eric Dumazet wrote: > Could you please add this patch and see if it helps on your machine ? > > [PATCH] VM : mm_struct's mmap_cache should be close to mmap_sem > > Avoids cache line dirtying I could, but I already know it's not going to help much. How do I know this? I already have 66% idle time when running with my patch (and without Nick Piggin's patch to take the mmap_sem for reading only). Interestingly, despite the idle time increasing from 10% to 66%, throughput triples... Saving some CPU time will probably only increase the idle time, I see no reason your patch would reduce contention and increase throughput. I'm not saying your patch doesn't make sense - it probably does. I just suspect it would have zero impact on this particular scenario, because of the already huge idle time. -- Politics is the struggle between those who want to make their country the best in the world, and those who believe it already is. Each group calls the other unpatriotic. From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4614B3FB.2090405@redhat.com> Date: Thu, 05 Apr 2007 04:31:55 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: missing madvise functionality References: <46128051.9000609@redhat.com> <46128CC2.9090809@redhat.com> <20070403172841.GB23689@one.firstfloor.org> <20070403125903.3e8577f4.akpm@linux-foundation.org> <4612B645.7030902@redhat.com> <20070403202937.GE355@devserv.devel.redhat.com> <4614A5CC.5080508@redhat.com> <20070405100848.db97d835.dada1@cosmosbay.com> In-Reply-To: <20070405100848.db97d835.dada1@cosmosbay.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Eric Dumazet Cc: Jakub Jelinek , Ulrich Drepper , Andrew Morton , Andi Kleen , Linux Kernel , linux-mm@kvack.org, Hugh Dickins List-ID: Eric Dumazet wrote: > Could you please add this patch and see if it helps on your machine ? > > [PATCH] VM : mm_struct's mmap_cache should be close to mmap_sem > > Avoids cache line dirtying I could, but I already know it's not going to help much. How do I know this? I already have 66% idle time when running with my patch (and without Nick Piggin's patch to take the mmap_sem for reading only). Interestingly, despite the idle time increasing from 10% to 66%, throughput triples... Saving some CPU time will probably only increase the idle time, I see no reason your patch would reduce contention and increase throughput. I'm not saying your patch doesn't make sense - it probably does. I just suspect it would have zero impact on this particular scenario, because of the already huge idle time. -- Politics is the struggle between those who want to make their country the best in the world, and those who believe it already is. Each group calls the other unpatriotic. -- 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: email@kvack.org