Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 22 Mar 2022 15:15:08 -0700
In-Reply-To: <20220322221517.2510440-1-eranian@google.com>
Message-Id: <20220322221517.2510440-5-eranian@google.com>
Mime-Version: 1.0
References: <20220322221517.2510440-1-eranian@google.com>
Subject: [PATCH v7 04/13] perf/x86/amd: add branch-brs helper event for Fam19h BRS
From:   Stephane Eranian <eranian@google.com>
To:     linux-kernel@vger.kernel.org
Cc:     peterz@infradead.org, kim.phillips@amd.com, acme@redhat.com,
        jolsa@redhat.com, songliubraving@fb.com, rafael@kernel.org,
        ravi.bangoria@amd.com, sandipan.das@amd.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

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>
---
 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 c7ac70d8ed9a..f7bce8364fe4 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,
 };
 
-- 
2.35.1.894.gb6a874cedc-goog