Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932344AbbFLSUX (ORCPT ); Fri, 12 Jun 2015 14:20:23 -0400 Received: from mga02.intel.com ([134.134.136.20]:36583 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755754AbbFLSUO (ORCPT ); Fri, 12 Jun 2015 14:20:14 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,602,1427785200"; d="scan'208";a="742306774" 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, peterz@infradead.org, matt.fleming@intel.com, will.auld@intel.com, linux-rdt@eclists.intel.com, vikas.shivappa@linux.intel.com Subject: [PATCH 03/10] x86/intel_rapl: Modify hot cpu notification handling for RAPL Date: Fri, 12 Jun 2015 11:17:10 -0700 Message-Id: <1434133037-25189-4-git-send-email-vikas.shivappa@linux.intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1434133037-25189-1-git-send-email-vikas.shivappa@linux.intel.com> References: <1434133037-25189-1-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 Content-Length: 2483 Lines: 73 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 cpumask_any_online_but 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 | 27 ++++++++++----------------- 1 file changed, 10 insertions(+), 17 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..987383e 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c +++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c @@ -524,18 +524,14 @@ 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; - } - } + i = cpumask_any_online_but(topology_core_cpumask(cpu), cpu); + if (i < nr_cpu_ids) + target = i; + /* * clear cpu from cpumask * if was set in cpumask and still some cpu on package, @@ -557,15 +553,12 @@ static void rapl_cpu_exit(int cpu) static void rapl_cpu_init(int cpu) { - int i, phys_id = topology_physical_package_id(cpu); + struct cpumask tmp; - /* 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, &rapl_cpu_mask, topology_core_cpumask(cpu)); + if (cpumask_empty(&tmp)) + cpumask_set_cpu(cpu, &rapl_cpu_mask); } static __init void rapl_hsw_server_quirk(void) -- 1.9.1 -- 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/