linux-kernel - [PATCH] perf report: Set PERF_SAMPLE_DATA

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Message-Id: <20220413075124.635589-1-leo.yan@linaro.org>
Date:   Wed, 13 Apr 2022 15:51:24 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Ravi Bangoria <ravi.bangoria@...ux.ibm.com>,
        James Clark <james.clark@....com>,
        German Gomez <german.gomez@....com>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Leo Yan <leo.yan@...aro.org>
Subject: [PATCH] perf report: Set PERF_SAMPLE_DATA_SRC bit for Arm SPE event

Since commit bb30acae4c4d ("perf report: Bail out --mem-mode if mem info
is not available") "perf mem report" and "perf report --mem-mode"
don't report result if the PERF_SAMPLE_DATA_SRC bit is missed in sample
type.

The commit ffab48705205 ("perf: arm-spe: Fix perf report --mem-mode")
partially fixes the issue.  It adds PERF_SAMPLE_DATA_SRC bit for Arm SPE
event, this allows the perf data file generated by kernel v5.18-rc1 or
later version can be reported properly.

On the other hand, perf tool still fails to be backward compatibility
for a data file recorded by an older version's perf which contains Arm
SPE trace data.  This patch is a workaround in reporting phase, when
detects ARM SPE PMU event and without PERF_SAMPLE_DATA_SRC bit, it will
force to set the bit in the sample type and give a warning info.

Fixes: bb30acae4c4d ("perf report: Bail out --mem-mode if mem info is not available")
Signed-off-by: Leo Yan <leo.yan@...aro.org>
---
 tools/perf/builtin-report.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 1ad75c7ba074..f26dd14eb852 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -353,6 +353,7 @@ static int report__setup_sample_type(struct report *rep)
 	struct perf_session *session = rep->session;
 	u64 sample_type = evlist__combined_sample_type(session->evlist);
 	bool is_pipe = perf_data__is_pipe(session->data);
+	struct evsel *evsel;
 
 	if (session->itrace_synth_opts->callchain ||
 	    session->itrace_synth_opts->add_callchain ||
@@ -407,6 +408,21 @@ static int report__setup_sample_type(struct report *rep)
 	}
 
 	if (sort__mode == SORT_MODE__MEMORY) {
+		/*
+		 * FIXUP: prior to kernel 5.18, Arm SPE missed to set
+		 * PERF_SAMPLE_DATA_SRC bit in sample type.  For backward
+		 * compatibility, set the bit if it's an old perf data file.
+		 */
+		evlist__for_each_entry(session->evlist, evsel) {
+			if (strstr(evsel->name, "arm_spe_") &&
+				!(sample_type & PERF_SAMPLE_DATA_SRC)) {
+				ui__warning("PERF_SAMPLE_DATA_SRC bit is not set "
+					    "for Arm SPE event.\n");
+				evsel->core.attr.sample_type |= PERF_SAMPLE_DATA_SRC;
+				sample_type |= PERF_SAMPLE_DATA_SRC;
+			}
+		}
+
 		if (!is_pipe && !(sample_type & PERF_SAMPLE_DATA_SRC)) {
 			ui__error("Selected --mem-mode but no mem data. "
 				  "Did you call perf record without -d?\n");
-- 
2.25.1