rtla-timerlat allows a *thread* latency threshold to be set via the -T/--thread option. However, the timerlat tracer calls this *total* latency (stop_tracing_total_us), and stops tracing also when the return-to-user latency is over the threshold.
Change the behavior of the timerlat BPF program to reflect what the timerlat tracer is doing, to avoid discrepancy between stopping collecting data in the BPF program and stopping tracing in the timerlat tracer.
Cc: stable@vger.kernel.org Fixes: e34293ddcebd ("rtla/timerlat: Add BPF skeleton to collect samples") Signed-off-by: Tomas Glozar tglozar@redhat.com --- tools/tracing/rtla/src/timerlat.bpf.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/tools/tracing/rtla/src/timerlat.bpf.c b/tools/tracing/rtla/src/timerlat.bpf.c index 084cd10c21fc..e2265b5d6491 100644 --- a/tools/tracing/rtla/src/timerlat.bpf.c +++ b/tools/tracing/rtla/src/timerlat.bpf.c @@ -148,6 +148,9 @@ int handle_timerlat_sample(struct trace_event_raw_timerlat_sample *tp_args) } else { update_main_hist(&hist_user, bucket); update_summary(&summary_user, latency, bucket); + + if (thread_threshold != 0 && latency_us >= thread_threshold) + set_stop_tracing(); }
return 0;
On Mon, Oct 06, 2025 at 04:31:00PM +0200, Tomas Glozar wrote:
rtla-timerlat allows a *thread* latency threshold to be set via the -T/--thread option. However, the timerlat tracer calls this *total* latency (stop_tracing_total_us), and stops tracing also when the return-to-user latency is over the threshold.
Change the behavior of the timerlat BPF program to reflect what the timerlat tracer is doing, to avoid discrepancy between stopping collecting data in the BPF program and stopping tracing in the timerlat tracer.
Cc: stable@vger.kernel.org Fixes: e34293ddcebd ("rtla/timerlat: Add BPF skeleton to collect samples") Signed-off-by: Tomas Glozar tglozar@redhat.com
tools/tracing/rtla/src/timerlat.bpf.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/tools/tracing/rtla/src/timerlat.bpf.c b/tools/tracing/rtla/src/timerlat.bpf.c index 084cd10c21fc..e2265b5d6491 100644 --- a/tools/tracing/rtla/src/timerlat.bpf.c +++ b/tools/tracing/rtla/src/timerlat.bpf.c @@ -148,6 +148,9 @@ int handle_timerlat_sample(struct trace_event_raw_timerlat_sample *tp_args) } else { update_main_hist(&hist_user, bucket); update_summary(&summary_user, latency, bucket);
if (thread_threshold != 0 && latency_us >= thread_threshold)set_stop_tracing();return 0; -- 2.51.0
Reviewed-by: Wander Lairson Costa wander@redhat.com
linux-stable-mirror@lists.linaro.org
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Tomas Glozar -
Wander Lairson Costa