On Sat, Jun 16, 2018 at 10:43:29PM +0900, Masami Hiramatsu wrote: > On Thu, 14 Jun 2018 18:01:13 -0700 > Joel Fernandes <joelaf@xxxxxxxxxx> wrote: > > > From: "Joel Fernandes (Google)" <joel@xxxxxxxxxxxxxxxxx> > > > > Currently, trace event triggers are called regardless of if the event > > filter checks pass or fail. Thus if one were to enable event triggers > > and filters at the same time, then the triggers will always be called > > even if the filter checks didn't pass. > > > > This is a problem for a usecase I was experimenting with: measuring the > > time preemption is disabled using synthetic events and dump the stack > > using the stacktrace trigger if the total preempt off time was greater > > than a threshold. Following are the commands for the same: > > > > Create synthetic event: > > > > echo 'preemptdisable u64 lat' >> \ > > /sys/kernel/debug/tracing/synthetic_events > > > > echo 'hist:keys=cpu:ts0=common_timestamp.usecs:scpu=cpu' >> \ > > /sys/kernel/debug/tracing/events/preemptirq/preempt_disable/trigger > > > > echo 'hist:keys=cpu:wakeup_lat=common_timestamp.usecs-$ts0:\ > > onmatch(preemptirq.preempt_disable).preemptdisable($wakeup_lat)' >> \ > > /sys/kernel/debug/tracing/events/preemptirq/preempt_enable/trigger > > > > Enable synthetic event: > > > > echo stacktrace > /sys/kernel/debug/tracing/events/synthetic/preemptdisable/trigger > > echo 'lat > 400' > /sys/kernel/debug/tracing/events/synthetic/preemptdisable/filter > > Have you tried if statement as below? > > echo "stacktrace if lat > 400" > /sys/kernel/debug/tracing/events/synthetic/preemptdisable/trigger > Yes I tried this and it works, thanks! Steven also suggested the same thing in his reply as well. thanks, - Joel -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
