tracing

Description

The trace script automates the process of enabling named sets of tracepoints and dumping the trace file over the SSH connection, then cleaning up after itself.

Usage

To run:

Usage: ./trace [USER@]HOST EVENTSET [EVENTSET...]

Valid EVENTSETs: fsi, occ, sbefifo, timer, sched

To stop the trace output and disable the tracepoints, hit Return.

For example, capturing the defined tracepoints for the sched event set:

$ ./trace root@my-bmc sched
+ set -eou pipefail
+ set -x
+ EVENT_fsi='fsi fsi_master_gpio'
+ EVENT_occ='occ hwmon_occ'
+ EVENT_sbefifo=sbefifo
+ EVENT_timer='timer/timer_start timer/timer_cancel timer/timer_expire_entry timer/timer_expire_exit'
+ EVENT_sched='sched/sched_switch sched/sched_wakeup sched/sched_wakeup_new sched/sched_waking'
+ trap on_exit EXIT
+ CAT_PID=1867
+ for elem in sched
+ eval 'trace=\${EVENT_${elem}}'
++ trace='${EVENT_sched}'
++ eval echo '${EVENT_sched}'
+++ echo sched/sched_switch sched/sched_wakeup sched/sched_wakeup_new sched/sched_waking
+ for event in '$(eval echo ${trace})'
+ echo 1
+ for event in '$(eval echo ${trace})'
+ echo 1
+ for event in '$(eval echo ${trace})'
+ echo 1
+ for event in '$(eval echo ${trace})'
+ echo 1
+ echo 1
+ read
+ cat /sys/kernel/debug/tracing/per_cpu/cpu0/trace_pipe
              sh-1866  [000] d.h. 201821.030000: sched_waking: comm=rngd pid=987 prio=120 target_cpu=000
              sh-1866  [000] dnh. 201821.030000: sched_wakeup: comm=rngd pid=987 prio=120 target_cpu=000
              sh-1866  [000] dn.. 201821.030000: sched_waking: comm=ksoftirqd/0 pid=6 prio=120 target_cpu=000
              sh-1866  [000] dn.. 201821.030000: sched_wakeup: comm=ksoftirqd/0 pid=6 prio=120 target_cpu=000
              sh-1866  [000] d... 201821.030000: sched_switch: prev_comm=sh prev_pid=1866 prev_prio=120 prev_state=R ==> next_comm=rngd next_pid=987 next_prio=120
            rngd-987   [000] d... 201821.030000: sched_switch: prev_comm=rngd prev_pid=987 prev_prio=120 prev_state=S ==> next_comm=ksoftirqd/0 next_pid=6 next_prio=120
     ksoftirqd/0-6     [000] d... 201821.030000: sched_switch: prev_comm=ksoftirqd/0 prev_pid=6 prev_prio=120 prev_state=S ==> next_comm=sh next_pid=1866 next_prio=120
              sh-1866  [000] d.h. 201821.030000: sched_waking: comm=phosphor-hwmon- pid=1188 prio=120 target_cpu=000
              sh-1866  [000] dnh. 201821.030000: sched_wakeup: comm=phosphor-hwmon- pid=1188 prio=120 target_cpu=000
              sh-1866  [000] d... 201821.030000: sched_switch: prev_comm=sh prev_pid=1866 prev_prio=120 prev_state=R ==> next_comm=phosphor-hwmon- next_pid=1188 next_prio=120
 phosphor-hwmon--1188  [000] d... 201821.030000: sched_switch: prev_comm=phosphor-hwmon- prev_pid=1188 prev_prio=120 prev_state=D ==> next_comm=sh next_pid=1866 next_prio=120
...
<RETURN>
...
+ kill 1867
+ on_exit
+ for elem in sched
+ eval 'trace=\${EVENT_${elem}}'
++ trace='${EVENT_sched}'
++ eval echo '${EVENT_sched}'
+++ echo sched/sched_switch sched/sched_wakeup sched/sched_wakeup_new sched/sched_waking
+ for event in '$(eval echo ${trace})'
+ echo 0
+ for event in '$(eval echo ${trace})'
+ echo 0
+ for event in '$(eval echo ${trace})'
+ echo 0
+ for event in '$(eval echo ${trace})'
+ echo 0
+ echo 0
+ on_exit
+ rm -f obmc-fsi-trace.Rz15GL