From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751645AbbLUOuN (ORCPT ); Mon, 21 Dec 2015 09:50:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52720 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751392AbbLUOuJ (ORCPT ); Mon, 21 Dec 2015 09:50:09 -0500 From: Prarit Bhargava To: linux-kernel@vger.kernel.org Cc: Prarit Bhargava , "Rafael J. Wysocki" , Radivoje Jovanovic , Seiichi Ikarashi , Mathias Krause , Ajay Thomas Subject: [PATCH 2/3] powercap, intel_rapl, implement check for minimum time window Date: Mon, 21 Dec 2015 09:50:02 -0500 Message-Id: <1450709403-780-3-git-send-email-prarit@redhat.com> In-Reply-To: <1450709403-780-1-git-send-email-prarit@redhat.com> References: <1450184532-21150-1-git-send-email-prarit@redhat.com> <1450709403-780-1-git-send-email-prarit@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Using an small value for the time window results in a bogus value for the time window. For example, [root@intel-chiefriver-03 linux]# echo 950 > /sys/devices/virtual/powercap/intel-rapl/intel-rapl\:0/constraint_0_time_window_us; egrep ^ /sys/devices/virtual/powercap/intel-rapl/intel-rapl\:0/constraint_0_time_window_us -bash: echo: write error: Invalid argument /sys/devices/virtual/powercap/intel-rapl/intel-rapl:0/constraint_0_time_window_us:1:4501502475370496 The Intel ASDM doesn't explicitly define a minimum time window. The MSR_RAPL_POWER_UNIT register, read during initialization, does specify a minimum time window unit so that can be used as a lower bound for error checking. After this change the minimum time window is properly clamped: [root@intel-chiefriver-03 linux]# echo 950 > /sys/devices/virtual/powercap/intel-rapl/intel-rapl\:0/constraint_0_time_window_us; egrep ^ /sys/devices/virtual/powercap/intel-rapl/intel-rapl\:0/constraint_0_time_window_us -bash: echo: write error: Invalid argument /sys/devices/virtual/powercap/intel-rapl/intel-rapl:0/constraint_0_time_window_us:1:976 Cc: "Rafael J. Wysocki" Cc: Prarit Bhargava Cc: Radivoje Jovanovic Cc: Seiichi Ikarashi Cc: Mathias Krause Cc: Ajay Thomas Signed-off-by: Prarit Bhargava --- drivers/powercap/intel_rapl.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c index f765b2c..14753e5 100644 --- a/drivers/powercap/intel_rapl.c +++ b/drivers/powercap/intel_rapl.c @@ -516,6 +516,7 @@ static int set_time_window(struct powercap_zone *power_zone, int id, u64 window) { struct rapl_domain *rd; + struct rapl_package *rp; int ret = 0; u64 max_window; @@ -524,12 +525,18 @@ static int set_time_window(struct powercap_zone *power_zone, int id, if (ret < 0) goto out; - if (window > max_window) { + rd = power_zone_to_rapl_domain(power_zone); + rp = find_package_by_id(rd->package_id); + /* + * The Intel ASDM doesn't explicitly define a minimum time window. + * The MSR_RAPL_POWER_UNIT register, read during initialization, + * does contain the smallest unit of time that can be measured. + */ + if ((window > max_window) || (window < rp->time_unit)) { ret = -EINVAL; goto out; } - rd = power_zone_to_rapl_domain(power_zone); switch (rd->rpl[id].prim_id) { case PL1_ENABLE: rapl_write_data_raw(rd, TIME_WINDOW1, window); -- 1.7.9.3