linux-kernel - [PATCH 04/13] perf/x86/amd: Support PERF_SAMPLE_WEIGHT using IBS OP

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Date:   Wed, 25 May 2022 15:09:29 +0530
From:   Ravi Bangoria <ravi.bangoria@....com>
To:     <peterz@...radead.org>, <acme@...nel.org>
CC:     <ravi.bangoria@....com>, <jolsa@...nel.org>, <namhyung@...nel.org>,
        <eranian@...gle.com>, <irogers@...gle.com>, <jmario@...hat.com>,
        <leo.yan@...aro.org>, <alisaidi@...zon.com>, <ak@...ux.intel.com>,
        <kan.liang@...ux.intel.com>, <dave.hansen@...ux.intel.com>,
        <hpa@...or.com>, <mingo@...hat.com>, <mark.rutland@....com>,
        <alexander.shishkin@...ux.intel.com>, <tglx@...utronix.de>,
        <bp@...en8.de>, <x86@...nel.org>,
        <linux-perf-users@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <sandipan.das@....com>, <ananth.narayan@....com>,
        <kim.phillips@....com>, <santosh.shukla@....com>
Subject: [PATCH 04/13] perf/x86/amd: Support PERF_SAMPLE_WEIGHT using IBS OP_DATA3[IbsDcMissLat]

IBS Op data3 provides data cache miss latency which can be passed as
sample->weight along with perf_mem_data_src. Note that sample->weight
will be populated only when PERF_SAMPLE_DATA_SRC is also set, although
both sample types are independent.

Signed-off-by: Ravi Bangoria <ravi.bangoria@....com>
---
 arch/x86/events/amd/ibs.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index 6626caeed6a1..5a6e278713f4 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -738,6 +738,12 @@ static void perf_ibs_get_mem_lvl(struct perf_event *event, u64 op_data2,
 		return;
 	}
 
+	/* Load latency (Data cache miss latency) */
+	if (data_src->mem_op == PERF_MEM_OP_LOAD &&
+	    event->attr.sample_type & PERF_SAMPLE_WEIGHT) {
+		data->weight.full = (op_data3 & IBS_DC_MISS_LAT_MASK) >> IBS_DC_MISS_LAT_SHIFT;
+	}
+
 	/* L2 Hit */
 	if ((op_data3 & IBS_L2_MISS_MASK) == 0) {
 		/* Erratum #1293 */
-- 
2.31.1