From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758027AbYDUDz7 (ORCPT ); Sun, 20 Apr 2008 23:55:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754660AbYDUDzt (ORCPT ); Sun, 20 Apr 2008 23:55:49 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:39497 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754476AbYDUDzi (ORCPT ); Sun, 20 Apr 2008 23:55:38 -0400 Date: Sun, 20 Apr 2008 15:33:17 -0700 From: Arjan van de Ven To: Andi Kleen Cc: Daniel Hazelton , Adrian Bunk , Alan Cox , Shawn Bohrer , Ingo Molnar , Andrew Morton , Linux Kernel Mailing List , Thomas Gleixner Subject: Re: x86: 4kstacks default Message-ID: <20080420153317.3c85db8e@laptopd505.fenrus.org> In-Reply-To: <480BA12A.4000307@firstfloor.org> References: <200804181737.m3IHbabI010051@hera.kernel.org> <20080420104444.GI1595@cs181133002.pp.htv.fi> <87y778aezh.fsf@basil.nowhere.org> <200804201144.33308.dhazelton@enter.net> <480B7CB2.3080002@firstfloor.org> <20080420114845.77bf3fed@laptopd505.fenrus.org> <480BA12A.4000307@firstfloor.org> Organization: Intel X-Mailer: Claws Mail 3.2.0 (GTK+ 2.12.5; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 20 Apr 2008 22:01:46 +0200 Andi Kleen wrote: > > > > These are real customer workloads; java based "many things going > > on" at a time showed several thousands of threads fin the system (a > > dozen or two per request, multiplied by the number of outstanding > > connections) for *real customers*. > > Several thousands or 50k? Several thousands sounds large, but not > entirely unreasonable, but it is far from 50k. it is you who keeps putting up the 50k argument. What I'm talking about is in the 10k to 20k range; and that is actual workloads by real customers. > > > That you don't take that serious, fair, you can take serious > > whatever you want. > > No I don't take 50k threads on 32bit serious. And I hope you do not > either. [ removed a bunch of stuff about 50k again ] > > > was the observation that fragmentation is fundamentally unsolvable. > > Where was that observation? it was in the commit message from me you quoted, and was rather widely discussed at the time. It's also basic math; the Linux VM gets to deal with both short and long lasting allocations; no matter how hard you try to get some degree of fragmentation; especially due to the 15:1 acceleration you get due to the lowmem issue. And before you say "you should use 64 bit on such machines"; I would love it if more people used 64 bit linux. Sadly the adoption rate of that is not very good still.... by far ;( > > > Yes 2.4 sucked a lot more than 2.6 does. But even 2.6 will (and > > does) have fragmentation issues. We don't have effective physical > > address based reclaim yet for higher order allocs. > > I don't see any evidence that there are serious order 1 fragmentation > issues on 2.6. I assume you're not asking me to give you customer confidential data from a previous job in public ;) >If you have any please post it. just like you're posting the evidence that 4k stacks overflows? Google scores: 1-order allocation failed 54000 pages do_IRQ: stack overflow 4560 pages -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org