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Subject[PATCH v1 1/2] perf cs-etm: Validate timestamp tracing in per-thread mode
Date
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>
---
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
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