From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932438Ab2AJTBo (ORCPT ); Tue, 10 Jan 2012 14:01:44 -0500 Received: from mga11.intel.com ([192.55.52.93]:56069 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756558Ab2AJTBm (ORCPT ); Tue, 10 Jan 2012 14:01:42 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="105628404" Subject: Re: [PATCH] x86,sched: Fix sched_smt_power_savings totally broken From: Suresh Siddha Reply-To: Suresh Siddha To: svaidy@linux.vnet.ibm.com Cc: Youquan Song , Peter Zijlstra , linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com, akpm@linux-foundation.org, stable@vger.kernel.org, arjan@linux.intel.com, len.brown@intel.com, anhua.xu@intel.com, chaohong.guo@intel.com, Youquan Song In-Reply-To: <20120110165129.GC17432@dirshya.in.ibm.com> References: <1326099367-4166-1-git-send-email-youquan.song@intel.com> <1326103578.2442.50.camel@twins> <20120110001445.GA20542@linux-youquan.bj.intel.com> <1326107156.2442.59.camel@twins> <20120110055856.GA23741@linux-youquan.bj.intel.com> <1326153163.2366.7.camel@sbsiddha-mobl2> <20120110165426.GA20681@linux-youquan.bj.intel.com> <20120110165129.GC17432@dirshya.in.ibm.com> Content-Type: text/plain; charset="UTF-8" Organization: Intel Date: Tue, 10 Jan 2012 11:01:13 -0800 Message-ID: <1326222073.6283.9.camel@sbsiddha-mobl2> Mime-Version: 1.0 X-Mailer: Evolution 2.32.3 (2.32.3-1.fc14) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2012-01-10 at 22:21 +0530, Vaidyanathan Srinivasan wrote: > * Youquan Song [2012-01-10 11:54:26]: > > > > > > Youquan, As far as I know both the > > > sched_smt_power_savings/sched_mc_power_savings are broken for atleast an > > > year. > > > > > > Have you checked the state of 'sched_mc_power_savings' to see if it is > > > working or gets addressed with your proposed patches? > > Thanks Suresh! > > > > We have verified that sched_mc_power_savings works well in mainline and > > -tip tree, only sched_smt_power_savings broken. > > Hi Suresh, > > My testing also shows that sched_mc works find and only sched_smt > suffers from the group capacity problem at the core level. > No. I just checked and it doesn't work as intended. On a 2 socket 8-core SMT system, I ran 8 cpu hoggers and just toggled 'sched_mc_power_savings' between 0 and 1 multiple times. Irrespective of the value, those 8 hoggers are distributed evenly between two sockets - 4 each and doesn't change their positions. So I can bet it doesn't work. thanks, suresh