Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752100Ab3FCGFb (ORCPT ); Mon, 3 Jun 2013 02:05:31 -0400 Received: from mout.gmx.net ([212.227.15.15]:57483 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751100Ab3FCGFX (ORCPT ); Mon, 3 Jun 2013 02:05:23 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX1+wGNJBNNWw1O3O2izXjRBRKJdmksdOM2uGMA11A+ d/iiYvo/JamXd1 Message-ID: <1370239514.5988.117.camel@marge.simpson.net> Subject: Re: [RFC PATCH] sched: smart wake-affine From: Mike Galbraith To: Michael Wang Cc: LKML , Ingo Molnar , Peter Zijlstra , Alex Shi , Namhyung Kim , Paul Turner , Andrew Morton , "Nikunj A. Dadhania" , Ram Pai Date: Mon, 03 Jun 2013 08:05:14 +0200 In-Reply-To: <51AC2EA2.7030106@linux.vnet.ibm.com> References: <51A43B16.9080801@linux.vnet.ibm.com> <51ABFF6A.60206@linux.vnet.ibm.com> <1370228941.5988.66.camel@marge.simpson.net> <51AC0CD4.9070302@linux.vnet.ibm.com> <1370231597.5988.79.camel@marge.simpson.net> <51AC2121.1060903@linux.vnet.ibm.com> <1370236944.5988.108.camel@marge.simpson.net> <51AC2EA2.7030106@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1733 Lines: 39 On Mon, 2013-06-03 at 13:50 +0800, Michael Wang wrote: > On 06/03/2013 01:22 PM, Mike Galbraith wrote: > [snip] > >> > >> I agree that this idea, in other work, 'stop wake-affine when current is > >> busy with wakeup' may miss the chance to bring benefit, although I could > >> not find such workload, but I can't do promise... > > > > Someday we'll find the perfect balance... likely the day before the sun > > turns into a red giant and melts the earth. > > Won't take so long ;-) > > I would like to stop the regression on pgbench firstly, as PeterZ > mentioned, if someone reported other regressions, we will know what is > missing, if fix is possible, we fix it, if cost is too high, then I say > we ignore the illegal income, after all, we could not benefit one in the > cost of sacrifice others... > > I'd like to fix the problem ASAP, it's really a big, urgent problem on > my point of view, but doesn't win enough attentions as I thought it will... I fully agree that it's a problem, but not that it's a regression. The "we became too buddy-centric" problem has existed for a long time, it's just that pgbench in 1:N mode shows us how much that pull pull pull can cost us in scalability. A much more interesting pgbench test (imho) would be with one server per socket. 1 server (mother of all work) driving a multi-socket sized load is just silly, can't possibly scale, so it's important that improving 1:N pgbench (we can, and need to) doesn't harm sane loads. -Mike -- 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/