Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755146AbbLQTrY (ORCPT ); Thu, 17 Dec 2015 14:47:24 -0500 Received: from mga11.intel.com ([192.55.52.93]:12302 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754935AbbLQTrV (ORCPT ); Thu, 17 Dec 2015 14:47:21 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,442,1444719600"; d="scan'208";a="873743680" From: "Fenghua Yu" To: "H. Peter Anvin" , "Ingo Molnar" , "Thomas Gleixner" , "Tony Luck" , "Ravi V Shankar" , "Peter Zijlstra" , "Tejun Heo" , "Marcelo Tosatti" Cc: "linux-kernel" , "x86" , Fenghua Yu , Vikas Shivappa Subject: [PATCH V16 01/11] x86/intel_cqm: Modify hot cpu notification handling Date: Thu, 17 Dec 2015 14:46:06 -0800 Message-Id: <1450392376-6397-2-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 1.8.0.1 In-Reply-To: <1450392376-6397-1-git-send-email-fenghua.yu@intel.com> References: <1450392376-6397-1-git-send-email-fenghua.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2883 Lines: 93 From: Fenghua Yu From: Vikas Shivappa - 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 Signed-off-by: Fenghua Yu --- 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 a316ca9..dd82bc7 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_starting(unsigned int cpu) @@ -1270,7 +1274,6 @@ static void intel_cqm_cpu_starting(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, -- 2.5.0 -- 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/