From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 16 May 2006 18:47:43 +0200 From: Andreas Mohr Subject: Re: [patch 00/14] remap_file_pages protection support Message-ID: <20060516164743.GA23893@rhlx01.fht-esslingen.de> References: <20060430172953.409399000@zion.home.lan> <4456D5ED.2040202@yahoo.com.au> <200605030225.54598.blaisorblade@yahoo.it> <445CC949.7050900@redhat.com> <445D75EB.5030909@yahoo.com.au> <4465E981.60302@yahoo.com.au> <20060513181945.GC9612@goober> <4469D3F8.8020305@yahoo.com.au> <20060516135135.GA28995@rhlx01.fht-esslingen.de> <20060516163111.GK9612@goober> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060516163111.GK9612@goober> Sender: owner-linux-mm@kvack.org Return-Path: To: Valerie Henson Cc: Nick Piggin , Ulrich Drepper , Blaisorblade , Andrew Morton , linux-kernel@vger.kernel.org, Linux Memory Management , Val Henson List-ID: Hi, On Tue, May 16, 2006 at 09:31:12AM -0700, Valerie Henson wrote: > On Tue, May 16, 2006 at 03:51:35PM +0200, Andreas Mohr wrote: > > > > I cannot offer much other than some random confirmation that from my own > > oprofiling, whatever I did (often running a load test script consisting of > > launching 30 big apps at the same time), find_vma basically always showed up > > very prominently in the list of vmlinux-based code (always ranking within the > > top 4 or 5 kernel hotspots, such as timer interrupts, ACPI idle I/O etc.pp.). > > call-tracing showed it originating from mmap syscalls etc., and AFAIR quite > > some find_vma activity from oprofile itself. > > This is important: Which kernel? I had some traces still showing find_vma prominently during a profiling run just yesterday, with a very fresh 2.6.17-rc4-ck1 (IOW, basically 2.6.17-rc4). I added some cache prefetching in the list traversal a while ago, and IIRC that improved profiling times there, but cache prefetching is very often a bandaid in search for a real solution: a better data-handling algorithm. Andreas Mohr -- 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