From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 16 May 2006 15:51:35 +0200 From: Andreas Mohr Subject: Re: [patch 00/14] remap_file_pages protection support Message-ID: <20060516135135.GA28995@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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4469D3F8.8020305@yahoo.com.au> Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Valerie Henson , Ulrich Drepper , Blaisorblade , Andrew Morton , linux-kernel@vger.kernel.org, Linux Memory Management , Val Henson List-ID: Hi, On Tue, May 16, 2006 at 11:30:32PM +1000, Nick Piggin wrote: > I also tried running kbuild under UML, and could not make find_vma take > much time either [in this case, the per-thread vma cache patch roughly > doubles the number of hits, from about 15%->30% (in the host)]. > > So I guess it's time to go back into my hole. If anyone does come across > a find_vma constrained workload (especially with threads), I'd be very > interested. 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. Profiling done on 512MB UP Athlon and P3/700, 2.6.16ish, current Debian. Sorry for the foggy report, I don't have those logs here right now. So yes, improving that part should help in general, but I cannot quite say that my machines are "constrained" by it. But you probably knew that already, otherwise you wouldn't have poked in there... ;) 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