Messages in this thread | | | Date | Fri, 5 Jun 2015 17:43:36 -0700 (PDT) | From | Vikas Shivappa <> | Subject | Re: [PATCH 03/10] x86/intel_rapl: Modify hot cpu notification handling for RAPL |
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+ 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.shivappa@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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