When tracing stops, there is no collision with other samples, so using PERF_AUX_FLAG_COLLISION does not accurately reflect the trace state and may mislead userspace.
Use PERF_AUX_FLAG_PARTIAL instead to indicate that tracing stopped and the record may contain gaps.
Signed-off-by: Leo Yan leo.yan@arm.com --- drivers/hwtracing/coresight/coresight-trbe.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c index b06885a08e082fd34f68d9588518807b5c47c86e..0caa4a6b437a3aa39fc6bcc72a23711b54f7c598 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.c +++ b/drivers/hwtracing/coresight/coresight-trbe.c @@ -669,21 +669,14 @@ static enum trbe_fault_action trbe_get_fault_act(struct perf_output_handle *hand }
/* - * Mark the buffer to indicate that there was a WRAP event by - * setting the COLLISION flag. This indicates to the user that - * the TRBE trace collection was stopped without stopping the - * ETE and thus there might be some amount of trace that was - * lost between the time the WRAP was detected and the IRQ - * was consumed by the CPU. - * - * Setting the TRUNCATED flag would move the event to STOPPED - * state unnecessarily, even when there is space left in the - * ring buffer. Using the COLLISION flag doesn't have this side - * effect. We only set TRUNCATED flag when there is no space - * left in the ring buffer. + * Mark the buffer to indicate that the trace is stopped by setting + * the PARTIAL flag. This indicates to the user that the TRBE trace + * collection was stopped without stopping the ETE and thus there + * might be some amount of trace that was lost between the time the + * TRBE event was detected and the IRQ was consumed by the CPU. */ if (!is_trbe_running(trbsr)) - perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION); + perf_aux_output_flag(handle, PERF_AUX_FLAG_PARTIAL);
if (is_trbe_wrap(trbsr)) return TRBE_FAULT_ACT_WRAP;