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From:   Leo Yan <leo.yan@linaro.org>
To:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        James Clark <james.clark@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Mike Leach <mike.leach@linaro.org>
Cc:     John Garry <john.g.garry@oracle.com>,
        Will Deacon <will@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
        Leo Yan <leo.yan@linaro.org>
Subject: [PATCH v1 RESEND 1/2] perf cs-etm: Validate timestamp tracing in per-thread mode
Date:   Sat, 14 Oct 2023 15:41:58 +0800
Message-Id: <20231014074159.1667880-2-leo.yan@linaro.org>
In-Reply-To: <20231014074159.1667880-1-leo.yan@linaro.org>
References: <20231014074159.1667880-1-leo.yan@linaro.org>
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So far, it's impossible to validate timestamp trace in Arm CoreSight when
the perf is in the per-thread mode.  E.g. for the command:

  perf record -e cs_etm/timestamp/ --per-thread -- ls

The command enables config 'timestamp' for 'cs_etm' event in the
per-thread mode.  In this case, the function cs_etm_validate_config()
directly bails out and skips validation.

Given profiled process can be scheduled on any CPUs in the per-thread
mode, this patch validates timestamp tracing for all CPUs when detect
the CPU map is empty.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: James Clark <james.clark@arm.com>
---
 tools/perf/arch/arm/util/cs-etm.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
index b8d6a953fd74..cf9ef9ba800b 100644
--- a/tools/perf/arch/arm/util/cs-etm.c
+++ b/tools/perf/arch/arm/util/cs-etm.c
@@ -205,8 +205,17 @@ static int cs_etm_validate_config(struct auxtrace_record *itr,
 	for (i = 0; i < cpu__max_cpu().cpu; i++) {
 		struct perf_cpu cpu = { .cpu = i, };
 
-		if (!perf_cpu_map__has(event_cpus, cpu) ||
-		    !perf_cpu_map__has(online_cpus, cpu))
+		/*
+		 * In per-cpu case, do the validation for CPUs to work with.
+		 * In per-thread case, the CPU map is empty.  Since the traced
+		 * program can run on any CPUs in this case, thus don't skip
+		 * validation.
+		 */
+		if (!perf_cpu_map__empty(event_cpus) &&
+		    !perf_cpu_map__has(event_cpus, cpu))
+			continue;
+
+		if (!perf_cpu_map__has(online_cpus, cpu))
 			continue;
 
 		err = cs_etm_validate_context_id(itr, evsel, i);
-- 
2.34.1