Commit 44175993 authored Mar 22, 2022 by Stephane Eranian Committed by Peter Zijlstra Apr 05, 2022

perf/x86/amd: Add branch-brs helper event for Fam19h BRS



Add a pseudo event called branch-brs to help use the FAM Fam19h
Branch Sampling feature (BRS). BRS samples taken branches, so it is best used
when sampling on a retired taken branch event (0xc4) which is what BRS
captures.  Instead of trying to remember the event code or actual event name,
users can simply do:

$ perf record -b -e cpu/branch-brs/ -c 1000037 .....

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220322221517.2510440-5-eranian@google.com

parent ada54345

arch/x86/events/amd/core.c

+15 −0

Original line number	Diff line number	Diff line
		@@ -1145,8 +1145,23 @@ static struct attribute_group group_caps_amd_brs = {
		.is_visible = amd_brs_is_visible,
		};

		EVENT_ATTR_STR(branch-brs, amd_branch_brs,
		"event=" __stringify(AMD_FAM19H_BRS_EVENT)"\n");

		static struct attribute *amd_brs_events_attrs[] = {
		EVENT_PTR(amd_branch_brs),
		NULL,
		};

		static struct attribute_group group_events_amd_brs = {
		.name = "events",
		.attrs = amd_brs_events_attrs,
		.is_visible = amd_brs_is_visible,
		};

		static const struct attribute_group *amd_attr_update[] = {
		&group_caps_amd_brs,
		&group_events_amd_brs,
		NULL,
		};