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Diffstat (limited to 'arch/x86/events/amd/core.c')
-rw-r--r--arch/x86/events/amd/core.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index d81eac2284ea..3eee59c64daa 100644
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -1255,6 +1255,18 @@ static void amd_pmu_sched_task(struct perf_event_context *ctx,
amd_pmu_brs_sched_task(ctx, sched_in);
}
+static u64 amd_pmu_limit_period(struct perf_event *event, u64 left)
+{
+ /*
+ * 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) && left > x86_pmu.lbr_nr)
+ left -= x86_pmu.lbr_nr;
+
+ return left;
+}
+
static __initconst const struct x86_pmu amd_pmu = {
.name = "AMD",
.handle_irq = amd_pmu_handle_irq,
@@ -1415,6 +1427,7 @@ static int __init amd_core_pmu_init(void)
if (boot_cpu_data.x86 >= 0x19 && !amd_brs_init()) {
x86_pmu.get_event_constraints = amd_get_event_constraints_f19h;
x86_pmu.sched_task = amd_pmu_sched_task;
+ x86_pmu.limit_period = amd_pmu_limit_period;
/*
* put_event_constraints callback same as Fam17h, set above
*/