Messages in this thread Patch in this message | | | From | David Carrillo-Cisneros <> | Subject | [PATCH v2 23/32] perf/x86/intel/cqm: use PERF_INACTIVE_*_READ_* flags in CQM | Date | Wed, 11 May 2016 16:02:23 -0700 |
| |
Use newly added pmu_event flags to: - Allow thread events to be read from any CPU even if not in ACTIVE state. Since inter-package values are polled, a thread's occupancy is always:
local occupancy (read from hw) + remote occupancy (polled values)
- Allow cpu/cgroup events to be read from any CPU in the package where they run. This potentially saves IPIs when the read function runs in the same package but in a distinct CPU than the event.
Since reading will always return a new value and inherit_stats is not supported (due to all children events sharing the same RMID), there is no need to read during sched_out of an event.
Reviewed-by: Stephane Eranian <eranian@google.com> Signed-off-by: David Carrillo-Cisneros <davidcc@google.com> --- arch/x86/events/intel/cqm.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/arch/x86/events/intel/cqm.c b/arch/x86/events/intel/cqm.c index 12f563d..9038112 100644 --- a/arch/x86/events/intel/cqm.c +++ b/arch/x86/events/intel/cqm.c @@ -2689,6 +2689,16 @@ static int intel_cqm_event_init(struct perf_event *event) */ event->pmu_event_flags |= PERF_CGROUP_NO_RECURSION; + /* Events in CQM PMU are per-package and can be read even when + * the cpu is not running the event. + */ + if (event->cpu < 0) { + WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK)); + event->pmu_event_flags |= PERF_INACTIVE_EV_READ_ANY_CPU; + } else { + event->pmu_event_flags |= PERF_INACTIVE_CPU_READ_PKG; + } + mutex_lock(&cqm_mutex); -- 2.8.0.rc3.226.g39d4020
| |