CQM is a strict per package facility. Use the proper cpumasks to lookup the
readers.
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
arch/x86/kernel/cpu/perf_event_intel_cqm.c | 34 ++++++++++-------------------
1 file changed, 12 insertions(+), 22 deletions(-)
--- a/arch/x86/kernel/cpu/perf_event_intel_cqm.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_cqm.c
@@ -1244,15 +1244,12 @@ 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;
+ int reader, pkg = topology_physical_package_id(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);
+ /* First online cpu in package becomes the reader */
+ reader = cpumask_any_and(topology_core_cpumask(cpu), &uncore_cpu_mask);
+ if (reader >= nr_cpu_ids)
+ cpumask_set_cpu(cpu, &cqm_cpumask);
}
static void intel_cqm_cpu_starting(unsigned int cpu)
@@ -1270,24 +1267,17 @@ static void intel_cqm_cpu_starting(unsig
static void intel_cqm_cpu_exit(unsigned int cpu)
{
- int phys_id = topology_physical_package_id(cpu);
- int i;
+ int target, pkg = topology_physical_package_id(cpu);
- /*
- * Is @cpu a designated cqm reader?
- */
+ /* Is @cpu the current cqm reader for this package ? */
if (!cpumask_test_and_clear_cpu(cpu, &cqm_cpumask))
return;
- for_each_online_cpu(i) {
- if (i == cpu)
- continue;
-
- if (phys_id == topology_physical_package_id(i)) {
- cpumask_set_cpu(i, &cqm_cpumask);
- break;
- }
- }
+ /* Find another online reader in this package */
+ target = cpumask_any_but(topology_core_cpumask(cpu), cpu);
+
+ if (target < nr_cpu_ids)
+ cpumask_set_cpu(target, &uncore_cpu_mask);
}
static int intel_cqm_cpu_notifier(struct notifier_block *nb,
