On 20/01/2023 15:43, James Clark wrote:
On 20/01/2023 10:34, Suzuki K Poulose wrote:
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
drivers/hwtracing/coresight/coresight-etm-perf.c | 16 ++++++++++++---- drivers/hwtracing/coresight/coresight-etm-perf.h | 2 ++ 2 files changed, 14 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);I had a look for somewhere that's only called once after the aux buffer is available to avoid the new tracking bit, but didn't find anywhere obvious. We can always move it later anyway.
Reviewed-by: James Clark james.clark@arm.com
Thanks, pushed to next
https://git.kernel.org/coresight/c/a646ca099b18
Suzuki