From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264937AbTLKNab (ORCPT ); Thu, 11 Dec 2003 08:30:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264938AbTLKNab (ORCPT ); Thu, 11 Dec 2003 08:30:31 -0500 Received: from mail-05.iinet.net.au ([203.59.3.37]:63955 "HELO mail.iinet.net.au") by vger.kernel.org with SMTP id S264937AbTLKNaa (ORCPT ); Thu, 11 Dec 2003 08:30:30 -0500 Message-ID: <3FD8715F.9070304@cyberone.com.au> Date: Fri, 12 Dec 2003 00:30:07 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030827 Debian/1.4-3 X-Accept-Language: en MIME-Version: 1.0 To: William Lee Irwin III CC: linux-kernel , Ingo Molnar , Rusty Russell , Anton Blanchard , "Martin J. Bligh" , "Nakajima, Jun" , Mark Wong Subject: Re: [CFT][RFC] HT scheduler References: <3FD3FD52.7020001@cyberone.com.au> <20031208155904.GF19412@krispykreme> <3FD50456.3050003@cyberone.com.au> <20031209001412.GG19412@krispykreme> <3FD7F1B9.5080100@cyberone.com.au> <3FD81BA4.8070602@cyberone.com.au> <3FD8317B.4060207@cyberone.com.au> <20031211115222.GC8039@holomorphy.com> <3FD86C70.5000408@cyberone.com.au> <20031211132301.GD8039@holomorphy.com> In-Reply-To: <20031211132301.GD8039@holomorphy.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org William Lee Irwin III wrote: >William Lee Irwin III wrote: > >>>If this thing is heavily threaded, it could be mm->page_table_lock. >>> > >On Fri, Dec 12, 2003 at 12:09:04AM +1100, Nick Piggin wrote: > >>I'm not sure how threaded it is, probably very. Would inline spinlocks >>help show up mm->page_table_lock? >>It really looks like .text.lock.futex though, doesn't it? Would that be >>the hashed futex locks? I wonder why it suddenly goes downhill past about >>140 rooms though. >> > >It will get contention anyway if they're all pounding on the same futex. >OTOH, if they're all threads in the same process, they can hit other >problems. I'll try to find out more about hackbench. > Oh, sorry I was talking about volanomark. hackbench AFAIK doesn't use futexes at all, just pipes, and is not threaded at all, so it looks like a different problem to the volanomark one. hackbench runs into trouble at large numbers of tasks too though.