From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [patch v7 0/21] sched: power aware scheduling Date: Tue, 30 Apr 2013 10:41:35 +0200 Message-ID: <20130430084135.GA21473@gmail.com> References: <1365040862-8390-1-git-send-email-alex.shi@intel.com> <516724F5.20504@kernel.org> <5167C9FA.8050406@intel.com> <20130412162348.GE2368@pd.tnic> <1365785311.5814.36.camel@marge.simpson.net> <516F19EE.5060309@kernel.org> <1366989087.30242.11.camel@marge.simpson.net> <1367298972.4616.41.camel@marge.simpson.net> <1367310625.4616.71.camel@marge.simpson.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-bk0-f46.google.com ([209.85.214.46]:56998 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759146Ab3D3Ilk (ORCPT ); Tue, 30 Apr 2013 04:41:40 -0400 Content-Disposition: inline In-Reply-To: <1367310625.4616.71.camel@marge.simpson.net> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Mike Galbraith Cc: Len Brown , Borislav Petkov , Alex Shi , mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, akpm@linux-foundation.org, arjan@linux.intel.com, pjt@google.com, namhyung@kernel.org, morten.rasmussen@arm.com, vincent.guittot@linaro.org, gregkh@linuxfoundation.org, preeti@linux.vnet.ibm.com, viresh.kumar@linaro.org, linux-kernel@vger.kernel.org, len.brown@intel.com, rafael.j.wysocki@intel.com, jkosina@suse.cz, clark.williams@gmail.com, tony.luck@intel.com, keescook@chromium.org, mgorman@suse.de, riel@redhat.com, Linux PM list * Mike Galbraith wrote: > On Tue, 2013-04-30 at 07:16 +0200, Mike Galbraith wrote: > > > Well now, that's not exactly what I expected to see for AIM7 compute. > > Filesystem is munching cycles otherwise used for compute when load is > > spread across the whole box vs consolidated. > > So AIM7 compute performance delta boils down to: powersaving stacks > tasks, so they pat single bit of spinning rust sequentially/gently. So AIM7 with real block IO improved, due to sequentiality. Does it improve if AIM7 works on an SSD, or into ramdisk? Which are the workloads where 'powersaving' mode hurts workload performance measurably? Thanks, Ingo