linux-kernel - [PATCH v2 4/6] perf amd ibs: Add Load Latency bits in raw dump

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Message-ID: <20241218121437.1717-5-ravi.bangoria@amd.com>
Date: Wed, 18 Dec 2024 12:14:35 +0000
From: Ravi Bangoria <ravi.bangoria@....com>
To: <peterz@...radead.org>, <mingo@...hat.com>, <namhyung@...nel.org>
CC: <ravi.bangoria@....com>, <acme@...nel.org>, <eranian@...gle.com>,
	<jolsa@...nel.org>, <irogers@...gle.com>, <kan.liang@...ux.intel.com>,
	<bp@...en8.de>, <x86@...nel.org>, <linux-perf-users@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <santosh.shukla@....com>,
	<ananth.narayan@....com>, <sandipan.das@....com>
Subject: [PATCH v2 4/6] perf amd ibs: Add Load Latency bits in raw dump

IBS OP PMU on Zen5 supports Load Latency filtering. Decode and dump Load
Latency filtering related bits into perf script raw dump.

Also add oneliner example in the perf-amd-ibs man page.

Signed-off-by: Ravi Bangoria <ravi.bangoria@....com>
---
 tools/perf/Documentation/perf-amd-ibs.txt |  9 +++++++++
 tools/perf/util/amd-sample-raw.c          | 14 ++++++++++++--
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/tools/perf/Documentation/perf-amd-ibs.txt b/tools/perf/Documentation/perf-amd-ibs.txt
index 2fd31d9d7b71..55f80beae037 100644
--- a/tools/perf/Documentation/perf-amd-ibs.txt
+++ b/tools/perf/Documentation/perf-amd-ibs.txt
@@ -85,6 +85,15 @@ System-wide profile, uOps event, sampling period: 100000, L3MissOnly (Zen4 onwar
 
 	# perf record -e ibs_op/cnt_ctl=1,l3missonly=1/ -c 100000 -a
 
+System-wide profile, cycles event, sampling period: 100000, LdLat filtering (Zen5
+onward)
+
+	# perf record -e ibs_op/ldlat=128/ -c 100000 -a
+
+	Supported load latency threshold values are 128 to 2048 (both inclusive).
+	Latency value which is a multiple of 128 incurs a little less profiling
+	overhead compared to other values.
+
 Per process(upstream v6.2 onward), uOps event, sampling period: 100000
 
 	# perf record -e ibs_op/cnt_ctl=1/ -c 100000 -p 1234
diff --git a/tools/perf/util/amd-sample-raw.c b/tools/perf/util/amd-sample-raw.c
index 9d0ce88e90e4..ac34b18ccc0c 100644
--- a/tools/perf/util/amd-sample-raw.c
+++ b/tools/perf/util/amd-sample-raw.c
@@ -19,6 +19,7 @@
 
 static u32 cpu_family, cpu_model, ibs_fetch_type, ibs_op_type;
 static bool zen4_ibs_extensions;
+static bool ldlat_cap;
 
 static void pr_ibs_fetch_ctl(union ibs_fetch_ctl reg)
 {
@@ -78,14 +79,20 @@ static void pr_ic_ibs_extd_ctl(union ic_ibs_extd_ctl reg)
 static void pr_ibs_op_ctl(union ibs_op_ctl reg)
 {
 	char l3_miss_only[sizeof(" L3MissOnly _")] = "";
+	char ldlat[sizeof(" LdLatThrsh __ LdLatEn _")] = "";
 
 	if (zen4_ibs_extensions)
 		snprintf(l3_miss_only, sizeof(l3_miss_only), " L3MissOnly %d", reg.l3_miss_only);
 
-	printf("ibs_op_ctl:\t%016llx MaxCnt %9d%s En %d Val %d CntCtl %d=%s CurCnt %9d\n",
+	if (ldlat_cap) {
+		snprintf(ldlat, sizeof(ldlat), " LdLatThrsh %2d LdLatEn %d",
+			 reg.ldlat_thrsh, reg.ldlat_en);
+	}
+
+	printf("ibs_op_ctl:\t%016llx MaxCnt %9d%s En %d Val %d CntCtl %d=%s CurCnt %9d%s\n",
 		reg.val, ((reg.opmaxcnt_ext << 16) | reg.opmaxcnt) << 4, l3_miss_only,
 		reg.op_en, reg.op_val, reg.cnt_ctl,
-		reg.cnt_ctl ? "uOps" : "cycles", reg.opcurcnt);
+		reg.cnt_ctl ? "uOps" : "cycles", reg.opcurcnt, ldlat);
 }
 
 static void pr_ibs_op_data(union ibs_op_data reg)
@@ -331,6 +338,9 @@ bool evlist__has_amd_ibs(struct evlist *evlist)
 	if (perf_env__find_pmu_cap(env, "ibs_op", "zen4_ibs_extensions"))
 		zen4_ibs_extensions = 1;
 
+	if (perf_env__find_pmu_cap(env, "ibs_op", "ldlat"))
+		ldlat_cap = 1;
+
 	if (ibs_fetch_type || ibs_op_type) {
 		if (!cpu_family)
 			parse_cpuid(env);
-- 
2.43.0