diff options
| -rw-r--r-- | arch/x86/events/core.c | 7 | ||||
| -rw-r--r-- | arch/x86/events/perf_event.h | 12 |
2 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 7ada9172b074..54f992e65252 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -1375,6 +1375,13 @@ int x86_perf_event_set_period(struct perf_event *event) return x86_pmu.set_topdown_event_period(event); /* + * decrease period by the depth of the BRS feature to get + * the last N taken branches and approximate the desired period + */ + if (has_branch_stack(event)) + period = amd_brs_adjust_period(period); + + /* * If we are way outside a reasonable range then just skip forward: */ if (unlikely(left <= -period)) { diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index 6f1265163c9f..d91ff2c6cefe 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -1263,6 +1263,14 @@ static inline bool amd_brs_active(void) return cpuc->brs_active; } +static inline s64 amd_brs_adjust_period(s64 period) +{ + if (period > x86_pmu.lbr_nr) + return period - x86_pmu.lbr_nr; + + return period; +} + #else /* CONFIG_CPU_SUP_AMD */ static inline int amd_pmu_init(void) @@ -1287,6 +1295,10 @@ static inline void amd_brs_disable_all(void) { } +static inline s64 amd_brs_adjust_period(s64 period) +{ + return period; +} #endif /* CONFIG_CPU_SUP_AMD */ static inline int is_pebs_pt(struct perf_event *event) |