From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754332AbcHSDBF (ORCPT ); Thu, 18 Aug 2016 23:01:05 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:51254 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753827AbcHSDBC (ORCPT ); Thu, 18 Aug 2016 23:01:02 -0400 X-IBM-Helo: d03dlp02.boulder.ibm.com X-IBM-MailFrom: ego@linux.vnet.ibm.com From: "Gautham R. Shenoy" To: "Rafael J. Wysocki" , Daniel Lezcano , Michael Ellerman , Benjamin Herrenschmidt , Michael Neuling , Paul Mackerras , Vaidyanathan Srinivasan Cc: Anton Blanchard , linux-pm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, "Gautham R. Shenoy" Subject: [RFC/PATCH 0/2] powernv:cpuidle: Enable winkle idle state Date: Fri, 19 Aug 2016 03:56:53 +0530 X-Mailer: git-send-email 1.8.3.1 X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16081822-8235-0000-0000-00000904A4D4 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00005614; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000181; SDB=6.00746583; UDB=6.00352005; IPR=6.00519116; BA=6.00004668; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00012381; XFM=3.00000011; UTC=2016-08-18 22:27:17 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16081822-8236-0000-0000-000034150E45 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-08-18_09:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1608180299 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Gautham R. Shenoy" Hi, The patches in these series enable support for Winkle idle state in CPU-Idle. The first patch is a platform-independent CPU-Idle patch that allows CPU-Idle states to be disabled at start (Currently they are all enabled by default). The second patch adds the winkle enablement for powernv-cpuidle. By default, the winkle idle-state is disabled. It can be enabled by writing zero to the per-cpu cpuidle sysfs control file named "disable". This series has been lightly tested on a 2-socket POWER8 system and the machine was pretty stable while running kernbench and ebizzy. I didn't see any regressions with those. I haven't yet evaluated the impact that these patches might have on latency sensitive workloads. I hope to do that in a day or two. On the power-savings front, I could observe 6-8% additional power-savings when winkle state was enabled on an idle system with SMT=on. With SMT=off, additional idle power-savings observed with winkle enabled were greater than 15%. The numbers indicate that it might be worth the while to pursue this! Gautham R. Shenoy (2): cpuidle: Allow idle-states to be disabled at start powernv:cpuidle: Enable winkle idle state in CPU-Idle. drivers/cpuidle/cpuidle-powernv.c | 44 ++++++++++++++++++++++++++++++++------- drivers/cpuidle/cpuidle.c | 7 +++++++ include/linux/cpuidle.h | 7 ++++++- 3 files changed, 49 insertions(+), 9 deletions(-) -- 1.9.4