On Wed, 08 Apr 2026 10:58:06 -0500 Tom Zanussi <[email protected]> wrote:
Hi Tom, > ->system is set when using fully-qualified variable names. For > instance: > > echo 'hist:keys=pid:ts0=common_timestamp.usecs' >> > sys/kernel/debug/tracing/events/sched/sched_waking/trigger > echo 'hist:keys=pid:ts0=common_timestamp.usecs' >> > /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger > echo > 'hist:keys=next_pid:lat0=common_timestamp.usecs-sched.sched_waking.$ts0:lat1=common_timestamp.usecs-sched.sched_wakeup.$ts0' > >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger > echo 'hist:keys=next_pid:vals=$lat0,$lat1' >> > /sys/kernel/debug/tracing/events/sched/sched_switch/trigger > > Here, the sched_switch trigger would error out if the unqualified $ts0 > variables were used instead of the fully-qualified ones because there's > no way to distinguish which $ts0 was meant. > Yep I see that now. I never had a need to use it before, but I probably should implement this in libtracefs to be safe. We should definitely add a selftest that tests this. There's one case that does use it but it doesn't use multiple ones. We should add a test that does so. trigger-multi-actions-accept.tc has the system, but it's not needed here. We should also have a test to test the output of theses lines. -- Steve
