[tip: perf/core] perf/x86/amd: Add branch-brs helper event for Fam19h BRS

From: tip-bot2 for Stephane Eranian
Date: Tue Apr 05 2022 - 07:24:03 EST


The following commit has been merged into the perf/core branch of tip:

Commit-ID: 44175993efbae04e8b2d7f7795ff512c3a726db0
Gitweb: https://git.kernel.org/tip/44175993efbae04e8b2d7f7795ff512c3a726db0
Author: Stephane Eranian <eranian@xxxxxxxxxx>
AuthorDate: Tue, 22 Mar 2022 15:15:08 -07:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Tue, 05 Apr 2022 10:24:37 +02:00

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@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220322221517.2510440-5-eranian@xxxxxxxxxx
---
arch/x86/events/amd/core.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index c7ac70d..f7bce83 100644
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -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,
};