Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756638AbYF0M5F (ORCPT ); Fri, 27 Jun 2008 08:57:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752085AbYF0M4w (ORCPT ); Fri, 27 Jun 2008 08:56:52 -0400 Received: from brmea-mail-3.Sun.COM ([192.18.98.34]:47285 "EHLO brmea-mail-3.sun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751782AbYF0M4v (ORCPT ); Fri, 27 Jun 2008 08:56:51 -0400 Date: Fri, 27 Jun 2008 08:54:12 -0400 From: David Collier-Brown Subject: Re: [RFC v1] Tunable sched_mc_power_savings=n In-reply-to: <20080627170514.7A88.KOSAKI.MOTOHIRO@jp.fujitsu.com> To: KOSAKI Motohiro Cc: Linux Kernel , Suresh B Siddha , Venkatesh Pallipadi , Ingo Molnar , Peter Zijlstra , Dipankar Sarma , Balbir Singh , Vatsa , Gautham R Shenoy Reply-to: davecb@sun.com Message-id: <4864E2F4.9080908@sun.com> MIME-version: 1.0 Content-type: text/plain; format=flowed; charset=us-ascii Content-transfer-encoding: 7BIT X-Accept-Language: en-us, en References: <20080625191100.GI21892@dirshya.in.ibm.com> <20080627170514.7A88.KOSAKI.MOTOHIRO@jp.fujitsu.com> User-Agent: Mozilla/5.0 (X11; U; SunOS sun4u; en-US; rv:1.7) Gecko/20041221 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1575 Lines: 40 KOSAKI Motohiro wrote: > Hi > > >>Advantages: >> >>* Enterprise workloads on large hardware configurations may need >> aggressive consolidation strategy >>* Performance impact on server is different from desktop or laptops. >> Interactivity is less of a concern on large enterprise servers while >> workload response times and performance per watt is more significant >>* Aggressive power savings even with marginal performance penalty is >> is a useful tunable for servers since it may provide good >> performance-per-watt at low utilisation >>* This tunable can influence other parts of scheduler like wakeup >> biasing for overall task consolidation > > > I'd like to know how many saving power. > if there are only small saving, I think this is not interesting feature. > > Do you expect how many percentage saving? > An experiment using DVFS on Xeon yeilded a 15-watt allowable reduction even under running a considerable TPC-W workload. Lesser loads allowed a 40-watt (out of 160) reduction. --dave -- David Collier-Brown | Always do right. This will gratify Sun Microsystems, Toronto | some people and astonish the rest davecb@sun.com | -- Mark Twain (905) 943-1983, cell: (647) 833-9377, (800) 555-9786 x56583 bridge: (877) 385-4099 code: 506 9191# -- 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/