The current vPMU can reuse the same pmc->perf_event for the same
hardware event via pmc_pause/resume_counter(), but this optimization
does not apply to a portion of the TSX events (e.g., "event=0x3c,in_tx=1,
in_tx_cp=1"), where event->attr.sample_period is legally zero at creation,
thus making the perf call to perf_event_period() meaningless (no need to
adjust sample period in this case), and instead causing such reusable
perf_events to be repeatedly released and created.
Avoid releasing zero sample_period events by checking is_sampling_event()
to follow the previously enable/disable optimization.
Signed-off-by: Like Xu <likexu@tencent.com>
Message-Id: <
20221207071506.15733-2-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
return false;
/* recalibrate sample period and check if it's accepted by perf core */
- if (perf_event_period(pmc->perf_event,
+ if (is_sampling_event(pmc->perf_event) &&
+ perf_event_period(pmc->perf_event,
get_sample_period(pmc, pmc->counter)))
return false;
static inline void pmc_update_sample_period(struct kvm_pmc *pmc)
{
- if (!pmc->perf_event || pmc->is_paused)
+ if (!pmc->perf_event || pmc->is_paused ||
+ !is_sampling_event(pmc->perf_event))
return;
perf_event_period(pmc->perf_event,