Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753830AbYC3PVu (ORCPT ); Sun, 30 Mar 2008 11:21:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752623AbYC3PVk (ORCPT ); Sun, 30 Mar 2008 11:21:40 -0400 Received: from eth7959.sa.adsl.internode.on.net ([150.101.82.22]:35216 "EHLO hawking.rebel.net.au" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752386AbYC3PVk (ORCPT ); Sun, 30 Mar 2008 11:21:40 -0400 Message-ID: <47EFB008.5080706@davidnewall.com> Date: Mon, 31 Mar 2008 01:51:44 +1030 From: David Newall User-Agent: Thunderbird 2.0.0.12 (X11/20080227) MIME-Version: 1.0 To: Manfred Spraul CC: Mike Galbraith , 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> <47EF9FC2.3050901@colorfullife.com> In-Reply-To: <47EF9FC2.3050901@colorfullife.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1160 Lines: 26 Manfred Spraul wrote: > 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 :-( You should revert it all. The scalability problem isn't good, but from what you're saying, the idea isn't ready yet. Revert it all, fix the problems at your leisure, and submit new patches then. -- 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/