6.18-stable review patch. If anyone has any objections, please let me know.
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From: Tomas Glozar tglozar@redhat.com
commit e4240db9336c25826a2d6634adcca86d5ee01bde upstream.
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") Reviewed-by: Wander Lairson Costa wander@redhat.com Link: https://lore.kernel.org/r/20251006143100.137255-1-tglozar@redhat.com Signed-off-by: Tomas Glozar tglozar@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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;