perf/x86/cstate: Allow reading the package statistics from local CPU

The MSR registers for reading the package residency counters are
available on every CPU of the package. To avoid doing unnecessary SMP
calls to read the values for these from the various CPUs inside a
package, allow reading them from any CPU of the package.

Suggested-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230912124432.3616761-2-tero.kristo@linux.intel.com

diff --git a/arch/x86/events/intel/cstate.c b/arch/x86/events/intel/cstate.c
index 96fffb2d521d2a992f02eed7ce072daba22764c9..cbeb6d2bf5b459470a8d2c383373ea45f05656d6 100644 (file)
--- a/arch/x86/events/intel/cstate.c
+++ b/arch/x86/events/intel/cstate.c
@@ -336,6 +336,9 @@ static int cstate_pmu_event_init(struct perf_event *event)
                cfg = array_index_nospec((unsigned long)cfg, PERF_CSTATE_PKG_EVENT_MAX);
                if (!(pkg_msr_mask & (1 << cfg)))
                        return -EINVAL;
+
+               event->event_caps |= PERF_EV_CAP_READ_ACTIVE_PKG;
+
                event->hw.event_base = pkg_msr[cfg].msr;
                cpu = cpumask_any_and(&cstate_pkg_cpu_mask,
                                      topology_die_cpumask(event->cpu));