From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <46151A05.3050505@redhat.com> Date: Thu, 05 Apr 2007 11:47:17 -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> <4614A7B1.60808@redhat.com> <20070405013225.4135b76d.akpm@linux-foundation.org> In-Reply-To: <20070405013225.4135b76d.akpm@linux-foundation.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Jakub Jelinek , Ulrich Drepper , Andi Kleen , Linux Kernel , linux-mm@kvack.org, Hugh Dickins List-ID: Andrew Morton wrote: > On Thu, 05 Apr 2007 03:39:29 -0400 Rik van Riel wrote: > >> Rik van Riel wrote: >> >>> MADV_DONTNEED, unpatched, 1000 loops >>> >>> real 0m13.672s >>> user 0m1.217s >>> sys 0m45.712s >>> >>> >>> MADV_DONTNEED, with patch, 1000 loops >>> >>> real 0m4.169s >>> user 0m2.033s >>> sys 0m3.224s >> I just noticed something fun with these numbers. >> >> Without the patch, the system (a quad core CPU) is 10% idle. >> >> With the patch, it is 66% idle - presumably I need Nick's >> mmap_sem patch. >> >> However, despite being 66% idle, the test still runs over >> 3 times as fast! > > Please quote the context switch rate when testing this stuff (I use vmstat 1). > I've seen it vary by a factor of 10,000 depending upon what's happening. About context switches 14000 per second. I'll go compile in Nick's patch to see if that makes things go faster. I expect it will. procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ r b swpd free buff cache si so bi bo in cs us sy id wa st 1 0 0 965232 250024 370848 0 0 0 0 1026 13914 13 21 67 0 0 1 0 0 965232 250024 370848 0 0 0 0 1018 14654 12 20 68 0 0 1 0 0 965232 250024 370848 0 0 0 0 1023 14006 12 21 67 0 0 -- 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