From: Suzuki K Poulose suzuki.poulose@arm.com
mainline inclusion from mainline-v6.3-rc1 commit a646ca099b18 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I85PIL CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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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 Signed-off-by: xiabing xiabing12@h-partners.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 d5ab38278abf..a0f63ea0ffbb 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -390,10 +390,18 @@ 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 */ diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.h b/drivers/hwtracing/coresight/coresight-etm-perf.h index 3e4f2ad5e193..edeb91551550 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.h +++ b/drivers/hwtracing/coresight/coresight-etm-perf.h @@ -47,12 +47,14 @@ struct etm_filters { * struct etm_event_data - Coresight specifics associated to an event * @work: Handle to free allocated memory outside IRQ context. * @mask: Hold the CPU(s) this event was set for. + * @aux_hwid_done: Whether a CPU has emitted the TraceID packet or not. * @snk_config: The sink configuration. * @path: An array of path, each slot for one CPU. */ struct etm_event_data { struct work_struct work; cpumask_t mask; + cpumask_t aux_hwid_done; void *snk_config; struct list_head * __percpu *path; };