diff options
| author | Tero Kristo <tero.kristo@linux.intel.com> | 2023-09-13 15:59:56 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2023-10-09 16:12:22 +0200 |
| commit | 1765bb61bb18a7b81f68806de6e8b8f5000f65bf (patch) | |
| tree | 37f1b540f8501cb51ece10002ac4bbb79f21f41c /kernel/events | |
| parent | 05276d4831fe023b6674a72bd6b8c5b39796e690 (diff) | |
perf/core: Allow reading package events from perf_event_read_local
Per-package perf events are typically registered with a single CPU only,
however they can be read across all the CPUs within the package.
Currently perf_event_read maps the event CPU according to the topology
information to avoid an unnecessary SMP call, however
perf_event_read_local deals with hard values and rejects a read with a
failure if the CPU is not the one exactly registered. Allow similar
mapping within the perf_event_read_local if the perf event in question
can support this.
This allows users like BPF code to read the package perf events properly
across different CPUs within a package.
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/20230913125956.3652667-1-tero.kristo@linux.intel.com
Diffstat (limited to 'kernel/events')
| -rw-r--r-- | kernel/events/core.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index af569196d760..708d474c2ede 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4425,6 +4425,9 @@ static int __perf_event_read_cpu(struct perf_event *event, int event_cpu) { u16 local_pkg, event_pkg; + if ((unsigned)event_cpu >= nr_cpu_ids) + return event_cpu; + if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) { int local_cpu = smp_processor_id(); @@ -4527,6 +4530,8 @@ int perf_event_read_local(struct perf_event *event, u64 *value, u64 *enabled, u64 *running) { unsigned long flags; + int event_oncpu; + int event_cpu; int ret = 0; /* @@ -4551,15 +4556,22 @@ int perf_event_read_local(struct perf_event *event, u64 *value, goto out; } + /* + * Get the event CPU numbers, and adjust them to local if the event is + * a per-package event that can be read locally + */ + event_oncpu = __perf_event_read_cpu(event, event->oncpu); + event_cpu = __perf_event_read_cpu(event, event->cpu); + /* If this is a per-CPU event, it must be for this CPU */ if (!(event->attach_state & PERF_ATTACH_TASK) && - event->cpu != smp_processor_id()) { + event_cpu != smp_processor_id()) { ret = -EINVAL; goto out; } /* If this is a pinned event it must be running on this CPU */ - if (event->attr.pinned && event->oncpu != smp_processor_id()) { + if (event->attr.pinned && event_oncpu != smp_processor_id()) { ret = -EBUSY; goto out; } @@ -4569,7 +4581,7 @@ int perf_event_read_local(struct perf_event *event, u64 *value, * or local to this CPU. Furthermore it means its ACTIVE (otherwise * oncpu == -1). */ - if (event->oncpu == smp_processor_id()) + if (event_oncpu == smp_processor_id()) event->pmu->read(event); *value = local64_read(&event->count); |