From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 5 Apr 2007 01:32:25 -0700 From: Andrew Morton Subject: Re: missing madvise functionality Message-Id: <20070405013225.4135b76d.akpm@linux-foundation.org> In-Reply-To: <4614A7B1.60808@redhat.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: Jakub Jelinek , Ulrich Drepper , Andi Kleen , Linux Kernel , linux-mm@kvack.org, Hugh Dickins List-ID: 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. -- 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