From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934269Ab3BTJh6 (ORCPT ); Wed, 20 Feb 2013 04:37:58 -0500 Received: from mail-ee0-f53.google.com ([74.125.83.53]:56238 "EHLO mail-ee0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932714Ab3BTJh4 (ORCPT ); Wed, 20 Feb 2013 04:37:56 -0500 Date: Wed, 20 Feb 2013 10:37:51 +0100 From: Ingo Molnar To: Alex Shi Cc: torvalds@linux-foundation.org, mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, akpm@linux-foundation.org, arjan@linux.intel.com, bp@alien8.de, pjt@google.com, namhyung@kernel.org, efault@gmx.de, vincent.guittot@linaro.org, gregkh@linuxfoundation.org, preeti@linux.vnet.ibm.com, viresh.kumar@linaro.org, linux-kernel@vger.kernel.org, morten.rasmussen@arm.com Subject: Re: [patch v5 04/15] sched: add sched balance policies in kernel Message-ID: <20130220093751.GA2444@gmail.com> References: <1361164062-20111-1-git-send-email-alex.shi@intel.com> <1361164062-20111-5-git-send-email-alex.shi@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1361164062-20111-5-git-send-email-alex.shi@intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Alex Shi wrote: > Current scheduler behavior is just consider for larger > performance of system. So it try to spread tasks on more cpu > sockets and cpu cores > > To adding the consideration of power awareness, the patchset > adds 2 kinds of scheduler policy: powersaving and balance. > They will use runnable load util in scheduler balancing. The > current scheduling is taken as performance policy. > > performance: the current scheduling behaviour, try to spread tasks > on more CPU sockets or cores. performance oriented. > powersaving: will pack tasks into few sched group until all LCPU in the > group is full, power oriented. > balance : will pack tasks into few sched group until group_capacity > numbers CPU is full, balance between performance and > powersaving. Hm, so in a previous review I suggested keeping two main policies: power-saving and performance, plus a third, default policy, which automatically switches between these two if/when the kernel has information about whether a system is on battery or on AC - and picking 'performance' when it has no information. Such an automatic policy would obviously be useful to users - and that is what makes such a feature really interesting and a step forward. I think Peter expressed similar views: we don't want many knobs and states, we want two major goals plus an (optional but default enabled) automatism. Is your 'balance' policy implementing that suggestion? If not, why not? Thanks, Ingo