diff options
| author | Suzuki K Poulose <suzuki.poulose@arm.com> | 2023-01-20 13:34:34 +0300 |
|---|---|---|
| committer | Suzuki K Poulose <suzuki.poulose@arm.com> | 2023-01-24 13:41:46 +0300 |
| commit | a646ca099b1811f23a7c1eee58aaf38628ec5e83 (patch) | |
| tree | bddc84cb2b0aade8cf306de6354291251f6b9f2a /drivers/hwtracing/coresight/coresight-etm-perf.c | |
| parent | 0c507af711df7e7b114fa6ec188e6d860cae29c1 (diff) | |
| download | linux-a646ca099b1811f23a7c1eee58aaf38628ec5e83.tar.xz | |
coresight: perf: Output trace id only once
With the dynamic traceid allocation scheme in, we output the
AUX_OUTPUT_HWID packet every time event->start() is called.
This could cause too many such records in the perf.data,
while only one per CPU throughout the life time of
the event is required. Make sure we only output it once.
Before this patch:
$ perf report -D | grep OUTPUT_HW_ID
...
AUX_OUTPUT_HW_ID events: 55 (18.3%)
After this patch:
$ perf report -D | grep OUTPUT_HW_ID
...
AUX_OUTPUT_HW_ID events: 5 ( 1.9%)
Cc: Mike Leach <mike.leach@linaro.org>
Cc: James Clark <james.clark@arm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20230120103434.864318-1-suzuki.poulose@arm.com
Diffstat (limited to 'drivers/hwtracing/coresight/coresight-etm-perf.c')
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-etm-perf.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 12fff661456e..a48c97da8165 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -495,10 +495,18 @@ static void etm_event_start(struct perf_event *event, int flags) if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF)) goto fail_disable_path; - /* output cpu / trace ID in perf record */ - hw_id = FIELD_PREP(CS_AUX_HW_ID_VERSION_MASK, CS_AUX_HW_ID_CURR_VERSION); - hw_id |= FIELD_PREP(CS_AUX_HW_ID_TRACE_ID_MASK, coresight_trace_id_read_cpu_id(cpu)); - perf_report_aux_output_id(event, hw_id); + /* + * output cpu / trace ID in perf record, once for the lifetime + * of the event. + */ + if (!cpumask_test_cpu(cpu, &event_data->aux_hwid_done)) { + cpumask_set_cpu(cpu, &event_data->aux_hwid_done); + hw_id = FIELD_PREP(CS_AUX_HW_ID_VERSION_MASK, + CS_AUX_HW_ID_CURR_VERSION); + hw_id |= FIELD_PREP(CS_AUX_HW_ID_TRACE_ID_MASK, + coresight_trace_id_read_cpu_id(cpu)); + perf_report_aux_output_id(event, hw_id); + } out: /* Tell the perf core the event is alive */ |