From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Gautham R. Shenoy" Subject: [RFC/PATCH 0/2] powernv:cpuidle: Enable winkle idle state Date: Fri, 19 Aug 2016 03:56:53 +0530 Message-ID: Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+glppe-linuxppc-embedded-2=m.gmane.org@lists.ozlabs.org Sender: "Linuxppc-dev" To: "Rafael J. Wysocki" , Daniel Lezcano , Michael Ellerman , Benjamin Herrenschmidt , Michael Neuling , Paul Mackerras , Vaidyanathan Srinivasan Cc: linux-kernel@vger.kernel.org, "Gautham R. Shenoy" , linuxppc-dev@lists.ozlabs.org, Anton Blanchard , linux-pm@vger.kernel.org List-Id: linux-pm@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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3sFghB4CfzzDr5P for ; Fri, 19 Aug 2016 08:27:22 +1000 (AEST) Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u7IMNlwe112426 for ; Thu, 18 Aug 2016 18:27:20 -0400 Received: from e31.co.us.ibm.com (e31.co.us.ibm.com [32.97.110.149]) by mx0b-001b2d01.pphosted.com with ESMTP id 24wg7fmnvg-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 18 Aug 2016 18:27:19 -0400 Received: from localhost by e31.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 18 Aug 2016 16:27:19 -0600 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 Message-Id: List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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