Documentation/trace/histogram-design.rst

367   # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0' >>
600   # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0' >>     | |
728   # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0' >> events/sched/sched_switch/trigger
800   # trigger info: hist:keys=next_pid:vals=hitcount:wakeup_lat=common_timestamp.usecs-$ts0:sort=hitcount:size=2048:clock=global [active]
832       ftrace_event_field name: next_pid
852   # echo '!hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0' >> events/sched/sched_switch/trigger
866 next_pid field on this sched_switch event, we retrieve the
871 could equivalently be written trace(wakeup_latency,$wakeup_lat,next_pid)
874 next_pid isn't, since it's just naming a field in the sched_switch
903 next_pid into the wakeup_latency synthetic event invocation, which
906   # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0: \
907           onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid)' >>
932   ||  | $next_pid   |<-+ |   +---------------------+
988    ||                  |+->| var = next_pid        |
1000    ||                  +-->| val for next_pid      |
1027     |                  |   | var_ref = $next_pid   |
1053 representing the variable, in this case next_pid, and one to actually
1059 $next_pid variable in the trace() action.
1075 $next_pid references be resolved but the $wakeup_lat reference as
1111 sched_switch event fields, next_pid and next_comm, to generate a
1112 wakeup_latency trace event.  The next_pid and next_comm event fields
1115   # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,next_comm)' >> /sys/kernel/tracing/events/sched/sched_switch/trigger
1170 next_pid and next_comm have values var.idx = 1, and var.idx = 2.  Note
1188   # trigger info: hist:keys=next_pid:vals=hitcount:wakeup_lat=common_timestamp.usecs-$ts0:sort=hitcount:size=2048:clock=global:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,next_comm) [active]
1220       ftrace_event_field name: next_pid
1252       name: next_pid
1278       var.name: next_pid
1282       ftrace_event_field name: next_pid
1308   # echo '!hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,next_comm)' >> /sys/kernel/tracing/events/sched/sched_switch/trigger
1334     | .synth_event   |    | $next_pid idx   |---|-+  | $wakeup_lat val |
1336                                    .            | +->| $next_pid val   |
1364   # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0: \
1370   # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0: \
1392   # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmax($wakeup_lat).save(next_comm,prev_pid,prev_prio,prev_comm)' >> events/sched/sched_switch/trigger
1462   # trigger info: hist:keys=next_pid:vals=hitcount:wakeup_lat=common_timestamp.usecs-$ts0:sort=hitcount:size=2048:clock=global:onmax($wakeup_lat).save(next_comm,prev_pid,prev_prio,prev_comm) [active]
1494       ftrace_event_field name: next_pid
1605   # echo '!hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmax($wakeup_lat).save(next_comm,prev_pid,prev_prio,prev_comm)' >> events/sched/sched_switch/trigger
1655   # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,prio)' >> events/sched/sched_switch/trigger
1753 normal variable, wakeup_lat, and to a normal field variable, next_pid,
1760   # trigger info: hist:keys=next_pid:vals=hitcount:wakeup_lat=common_timestamp.usecs-$ts0:sort=hitcount:size=2048:clock=global:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,prio) [active]
1792       ftrace_event_field name: next_pid
1824       name: next_pid
1850       var.name: next_pid
1854       ftrace_event_field name: next_pid
1866   # echo '!hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,prio)' >> events/sched/sched_switch/trigger
1892   # echo 'hist:keys=next_pid:woken_pid=$waking_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,$woken_pid,next_comm)' >> events/sched/sched_switch/trigger
1983   # trigger info: hist:keys=next_pid:vals=hitcount:woken_pid=$waking_pid,wakeup_lat=common_timestamp.usecs-$ts0:sort=hitcount:size=2048:clock=global:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,$woken_pid,next_comm) [active]
2026       ftrace_event_field name: next_pid
2111   # echo '!hist:keys=next_pid:woken_pid=$waking_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,$woken_pid,next_comm)' >> events/sched/sched_switch/trigger