On 27/08/2023 14:35, Leo Yan wrote:
When users pass the option '--timestamp' or '-T' in the record command, all events will set the PERF_SAMPLE_TIME bit in the attribution. In this case, the AUX event will record the kernel timestamp, but it doesn't mean Arm CoreSight enables timestamp packets in its hardware tracing.
If the option '--timestamp' or '-T' is set, this patch always enables Arm CoreSight timestamp, as a result, the bit 28 in event's config is to be set.
Before:
# perf record -e cs_etm// --per-thread --timestamp -- ls # perf script --header-only ... # event : name = cs_etm//, , id = { 69 }, type = 12, size = 136, config = 0, { sample_period, sample_freq } = 1, sample_type = IP|TID|TIME|CPU|IDENTIFIER, read_format = ID|LOST, disabled = 1, enable_on_exec = 1, sample_id_all = 1, exclude_guest = 1 ...
After:
# perf record -e cs_etm// --per-thread --timestamp -- ls # perf script --header-only ... # event : name = cs_etm//, , id = { 49 }, type = 12, size = 136, config = 0x10000000, { sample_period, sample_freq } = 1, sample_type = IP|TID|TIME|CPU|IDENTIFIER, read_format = ID|LOST, disabled = 1, enable_on_exec = 1, sample_id_all = 1, exclude_guest = 1 ...
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 | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c index cf9ef9ba800b..58c506e9788d 100644 --- a/tools/perf/arch/arm/util/cs-etm.c +++ b/tools/perf/arch/arm/util/cs-etm.c @@ -442,6 +442,15 @@ static int cs_etm_recording_options(struct auxtrace_record *itr, "contextid", 1); }
- /*
* When the option '--timestamp' or '-T' is enabled, the PERF_SAMPLE_TIME* bit is set for all events. In this case, always enable Arm CoreSight* timestamp tracing.*/- if (opts->sample_time_set)
evsel__set_config_if_unset(cs_etm_pmu, cs_etm_evsel,"timestamp", 1);- /* Add dummy event to keep tracking */ err = parse_event(evlist, "dummy:u"); if (err)