Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965305AbbLRVeH (ORCPT ); Fri, 18 Dec 2015 16:34:07 -0500 Received: from terminus.zytor.com ([198.137.202.10]:59059 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964992AbbLRVeD (ORCPT ); Fri, 18 Dec 2015 16:34:03 -0500 Date: Fri, 18 Dec 2015 13:33:50 -0800 From: tip-bot for Fenghua Yu Message-ID: Cc: tglx@linutronix.de, mingo@kernel.org, fenghua.yu@intel.com, vikas.shivappa@linux.intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org Reply-To: tglx@linutronix.de, linux-kernel@vger.kernel.org, hpa@zytor.com, vikas.shivappa@linux.intel.com, fenghua.yu@intel.com, mingo@kernel.org In-Reply-To: <1450392376-6397-2-git-send-email-fenghua.yu@intel.com> References: <1450392376-6397-2-git-send-email-fenghua.yu@intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/cache] x86/intel_cqm: Modify hot cpu notification handling Git-Commit-ID: 8a91dc4e92327b61fbe5941d25e74660e2a44579 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3285 Lines: 98 Commit-ID: 8a91dc4e92327b61fbe5941d25e74660e2a44579 Gitweb: http://git.kernel.org/tip/8a91dc4e92327b61fbe5941d25e74660e2a44579 Author: Fenghua Yu AuthorDate: Thu, 17 Dec 2015 14:46:06 -0800 Committer: H. Peter Anvin CommitDate: Fri, 18 Dec 2015 13:17:55 -0800 x86/intel_cqm: Modify hot cpu notification handling 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 Link: http://lkml.kernel.org/r/1450392376-6397-2-git-send-email-fenghua.yu@intel.com 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, -- 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/