Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756589AbbHFVzl (ORCPT ); Thu, 6 Aug 2015 17:55:41 -0400 Received: from mga14.intel.com ([192.55.52.115]:39097 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753045AbbHFVzT (ORCPT ); Thu, 6 Aug 2015 17:55:19 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,625,1432623600"; d="scan'208";a="743717957" From: Vikas Shivappa To: vikas.shivappa@intel.com Cc: linux-kernel@vger.kernel.org, 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 1/9] x86/intel_cqm: Modify hot cpu notification handling Date: Thu, 6 Aug 2015 14:55:09 -0700 Message-Id: <1438898117-3692-2-git-send-email-vikas.shivappa@linux.intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1438898117-3692-1-git-send-email-vikas.shivappa@linux.intel.com> References: <1438898117-3692-1-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: 2736 Lines: 88 - In cqm_pick_event_reader, use the existing package<->core map instead of looping through all cpus in cqm_cpumask. - In intel_cqm_cpu_exit, use the same map instead of looping through all online cpus. In large systems with large number of cpus the time taken to loop may be expensive and also the time increases linearly. Signed-off-by: Vikas Shivappa --- arch/x86/kernel/cpu/perf_event_intel_cqm.c | 34 +++++++++++++++--------------- 1 file changed, 17 insertions(+), 17 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event_intel_cqm.c b/arch/x86/kernel/cpu/perf_event_intel_cqm.c index 63eb68b..916bef9 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_cqm.c +++ b/arch/x86/kernel/cpu/perf_event_intel_cqm.c @@ -62,6 +62,12 @@ static LIST_HEAD(cache_groups); */ static cpumask_t cqm_cpumask; +/* + * Temporary cpumask used during hot cpu notificaiton handling. The usage + * is serialized by hot cpu locks. + */ +static cpumask_t tmp_cpumask; + #define RMID_VAL_ERROR (1ULL << 63) #define RMID_VAL_UNAVAIL (1ULL << 62) @@ -1244,15 +1250,13 @@ static struct pmu intel_cqm_pmu = { static inline void cqm_pick_event_reader(int cpu) { - int phys_id = topology_physical_package_id(cpu); - int i; + cpumask_and(&tmp_cpumask, &cqm_cpumask, topology_core_cpumask(cpu)); - for_each_cpu(i, &cqm_cpumask) { - if (phys_id == topology_physical_package_id(i)) - return; /* already got reader for this socket */ - } - - cpumask_set_cpu(cpu, &cqm_cpumask); + /* + * Pick a reader if there isn't one already. + */ + if (cpumask_empty(&tmp_cpumask)) + cpumask_set_cpu(cpu, &cqm_cpumask); } static void intel_cqm_cpu_prepare(unsigned int cpu) @@ -1270,7 +1274,6 @@ static void intel_cqm_cpu_prepare(unsigned int cpu) static void intel_cqm_cpu_exit(unsigned int cpu) { - int phys_id = topology_physical_package_id(cpu); int i; /* @@ -1279,15 +1282,12 @@ static void intel_cqm_cpu_exit(unsigned int cpu) if (!cpumask_test_and_clear_cpu(cpu, &cqm_cpumask)) return; - for_each_online_cpu(i) { - if (i == cpu) - continue; + cpumask_and(&tmp_cpumask, topology_core_cpumask(cpu), cpu_online_mask); + cpumask_clear_cpu(cpu, &tmp_cpumask); + i = cpumask_any(&tmp_cpumask); - if (phys_id == topology_physical_package_id(i)) { - cpumask_set_cpu(i, &cqm_cpumask); - break; - } - } + if (i < nr_cpu_ids) + cpumask_set_cpu(i, &cqm_cpumask); } static int intel_cqm_cpu_notifier(struct notifier_block *nb, -- 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/