From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753911AbbGAWYO (ORCPT ); Wed, 1 Jul 2015 18:24:14 -0400 Received: from mga09.intel.com ([134.134.136.24]:54209 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750808AbbGAWXr (ORCPT ); Wed, 1 Jul 2015 18:23:47 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,388,1432623600"; d="scan'208";a="756840811" From: Vikas Shivappa To: linux-kernel@vger.kernel.org Cc: vikas.shivappa@intel.com, x86@kernel.org, hpa@zytor.com, tglx@linutronix.de, mingo@kernel.org, tj@kernel.org, peterz@infradead.org, matt.fleming@intel.com, will.auld@intel.com, glenn.p.williamson@intel.com, kanaka.d.juvva@intel.com, vikas.shivappa@linux.intel.com Subject: [PATCH 2/9] x86/intel_rapl: Modify hot cpu notification handling for RAPL Date: Wed, 1 Jul 2015 15:21:03 -0700 Message-Id: <1435789270-27010-3-git-send-email-vikas.shivappa@linux.intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1435789270-27010-1-git-send-email-vikas.shivappa@linux.intel.com> References: <1435789270-27010-1-git-send-email-vikas.shivappa@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch modifies the hot cpu notification handling in Intel Running Average Power Limit(RAPL) driver. - to add a cpu reader to the rapl_cpumask(which has one cpu per package set) it uses the existing package<->core map instead of looping through all cpus in rapl_cpumask. - to search for the next online sibling during hot cpu exit, it uses the same mapping instead of looping all online cpus. In large systems with large number of cpus the time taken to loop may be expensive and also the time increase linearly. Signed-off-by: Vikas Shivappa --- arch/x86/kernel/cpu/perf_event_intel_rapl.c | 35 ++++++++++++++--------------- 1 file changed, 17 insertions(+), 18 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event_intel_rapl.c b/arch/x86/kernel/cpu/perf_event_intel_rapl.c index 358c54a..c5ab686 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c +++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c @@ -132,6 +132,12 @@ static struct pmu rapl_pmu_class; static cpumask_t rapl_cpu_mask; static int rapl_cntr_mask; +/* + * Temporary cpumask used during hot cpu notificaiton handling. The usage + * is serialized by hot cpu locks. + */ +static cpumask_t tmp_cpumask; + static DEFINE_PER_CPU(struct rapl_pmu *, rapl_pmu); static DEFINE_PER_CPU(struct rapl_pmu *, rapl_pmu_to_free); @@ -524,18 +530,16 @@ static struct pmu rapl_pmu_class = { static void rapl_cpu_exit(int cpu) { struct rapl_pmu *pmu = per_cpu(rapl_pmu, cpu); - int i, phys_id = topology_physical_package_id(cpu); int target = -1; + int i; /* find a new cpu on same package */ - for_each_online_cpu(i) { - if (i == cpu) - continue; - if (phys_id == topology_physical_package_id(i)) { - target = i; - break; - } - } + cpumask_and(&tmp_cpumask, topology_core_cpumask(cpu), cpu_online_mask); + cpumask_clear_cpu(cpu, &tmp_cpumask); + i = cpumask_any(&tmp_cpumask); + if (i < nr_cpu_ids) + target = i; + /* * clear cpu from cpumask * if was set in cpumask and still some cpu on package, @@ -557,15 +561,10 @@ static void rapl_cpu_exit(int cpu) static void rapl_cpu_init(int cpu) { - int i, phys_id = topology_physical_package_id(cpu); - - /* check if phys_is is already covered */ - for_each_cpu(i, &rapl_cpu_mask) { - if (phys_id == topology_physical_package_id(i)) - return; - } - /* was not found, so add it */ - cpumask_set_cpu(cpu, &rapl_cpu_mask); + /* check if cpu's package is already covered.If not, add it.*/ + cpumask_and(&tmp_cpumask, &rapl_cpu_mask, topology_core_cpumask(cpu)); + if (cpumask_empty(&tmp_cpumask)) + cpumask_set_cpu(cpu, &rapl_cpu_mask); } static __init void rapl_hsw_server_quirk(void) -- 1.9.1