+ Andi, Stephan, Boris and Jacob for RAPL patch
On Thu, 4 Jun 2015, Vikas Shivappa wrote:
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 <vikas.shiva...@linux.intel.com>
---
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
--
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