Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753471AbYC3OMc (ORCPT ); Sun, 30 Mar 2008 10:12:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752262AbYC3OMX (ORCPT ); Sun, 30 Mar 2008 10:12:23 -0400 Received: from fg-out-1718.google.com ([72.14.220.156]:55046 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752257AbYC3OMW (ORCPT ); Sun, 30 Mar 2008 10:12:22 -0400 Message-ID: <47EF9FC2.3050901@colorfullife.com> Date: Sun, 30 Mar 2008 16:12:18 +0200 From: Manfred Spraul User-Agent: Thunderbird 2.0.0.12 (X11/20080226) MIME-Version: 1.0 To: Mike Galbraith CC: Linux Kernel Mailing List , paulmck@linux.vnet.ibm.com, Nadia Derbey , Andrew Morton , Peter Zijlstra , Pavel Emelianov Subject: Re: Scalability requirements for sysv ipc (+namespaces broken with SEM_UNDO) References: <47E382DB.70503@colorfullife.com> <47E3ADE3.4030304@bull.net> <47E3B924.3000304@colorfullife.com> <20080321141339.GB9618@linux.vnet.ibm.com> <47E3DD8C.4000904@colorfullife.com> <1206164608.3659.11.camel@marge.simson.net> <47E4DB06.3020003@colorfullife.com> <1206186832.4545.1.camel@marge.simson.net> <47E51637.8060102@colorfullife.com> <47E55945.10109@colorfullife.com> <1206460206.4414.21.camel@marge.simson.net> In-Reply-To: <1206460206.4414.21.camel@marge.simson.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1023 Lines: 28 Mike Galbraith wrote: > On Sat, 2008-03-22 at 20:08 +0100, Manfred Spraul wrote: > > >> just the normal performance of 2.6.25-rc3 is abyssimal, 55 to 60% slower >> than 2.6.18.8: >> > > After manually reverting 3e148c79938aa39035669c1cfa3ff60722134535, > 2.6.25.git scaled linearly We can't just revert that patch: with IDR, a global lock is mandatory :-( We must either revert the whole idea of using IDR or live with the reduced scalability. Actually, there are further bugs: the undo structures are not namespace-aware, thus semop with SEM_UNDO, unshare, create new array with same id, but more semaphores, another semop with SEM_UNDO will corrupt kernel memory :-( I'll try to clean up the bugs first, then I'll look at the scalability again. -- Manfred -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/