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[PATCH 02/11] x86/intel_rapl: Modify hot cpu notification handling

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 - In rapl_cpu_init, use the existing package<->core map instead of
 looping through all cpus in rapl_cpumask.

 - In rapl_cpu_exit, use 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 <vikas.shivappa@linux.intel.com>
---
 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 5cbd4e6..3f3fb4c 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);
 
@@ -523,18 +529,16 @@ 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,
@@ -556,15 +560,10 @@ 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

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[PATCH V14 0/9] Intel cache allocation and Hot cpu handling changes to cqm, rapl Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2015-09-09 21:30 +0200
  [PATCH 10/11] x86,cgroup/intel_rdt : Add intel_rdt cgroup documentation Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2015-09-09 21:30 +0200
  [PATCH 05/11] x86/intel_rdt: Add Class of service management Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2015-09-09 21:30 +0200
  [PATCH 02/11] x86/intel_rapl: Modify hot cpu notification handling Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2015-09-09 21:30 +0200
  [PATCH 03/11] x86/intel_rdt: Cache Allocation documentation Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2015-09-09 21:30 +0200
  [PATCH 07/11] x86/intel_rdt: Implement scheduling support for Intel RDT Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2015-09-09 21:30 +0200
  [PATCH 08/11] x86/intel_rdt: Hot cpu support for Cache Allocation Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2015-09-09 21:30 +0200
  [PATCH 06/11] x86/intel_rdt: Add L3 cache capacity bitmask management Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2015-09-09 21:30 +0200
  [PATCH 11/11] x86,cgroup/intel_rdt : Add a cgroup interface to manage Intel cache allocation Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2015-09-09 21:30 +0200
  [PATCH 01/11] x86/intel_cqm: Modify hot cpu notification handling Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2015-09-09 21:30 +0200
  [PATCH 04/11] x86/intel_rdt: Add support for Cache Allocation detection Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2015-09-09 21:30 +0200
  [PATCH 09/11] x86/intel_rdt: Intel haswell Cache Allocation enumeration Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2015-09-09 21:30 +0200

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