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Subject[PATCH 65/66] perf python: Add tracepoint example
Date
From: Jiri Olsa <jolsa@kernel.org>

To show how to enable a tracepoint and access its fields.

Committer note:

Testing it:

# ls -l /tmp/build/perf/python/perf.so
-rwxrwxr-x. 1 acme acme 1563256 Jul 12 16:19 /tmp/build/perf/python/perf.so
# export PYTHONPATH=/tmp/build/perf/python/
# tools/perf/python/tracepoint.py 2> /dev/null | head -200 | tail -10
time 76345337296548 prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=tracepoint.py- next_pid=18479 next_prio=120
time 76345338520479 prev_comm=gnome-shelln-b prev_pid=2186 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/1 next_pid=0 next_prio=120
time 76345337309942 prev_comm=tracepoint.py- prev_pid=18479 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/0 next_pid=0 next_prio=120
time 76345337312302 prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=tracepoint.py- next_pid=18479 next_prio=120
time 76345337324927 prev_comm=tracepoint.py- prev_pid=18479 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/0 next_pid=0 next_prio=120
time 76345337327115 prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=tracepoint.py- next_pid=18479 next_prio=120
time 76345338621750 prev_comm=swapper/2 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=rcuos/2 next_pid=29 next_prio=120
time 76345338607922 prev_comm=swapper/3 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=rcu_sched next_pid=7 next_prio=120
time 76345337338817 prev_comm=tracepoint.py- prev_pid=18479 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/0 next_pid=0 next_prio=120
time 76345338627156 prev_comm=swapper/1 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=head-terminal- next_pid=18480 next_prio=120
#
# strip /tmp/build/perf/python/perf.so
# ls -l /tmp/build/perf/python/perf.so
-rwxrwxr-x. 1 acme acme 319616 Jul 12 16:25 /tmp/build/perf/python/perf.so

Reported-and-Tested-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1468148882-10362-10-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/python/tracepoint.py | 47 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)
create mode 100755 tools/perf/python/tracepoint.py

diff --git a/tools/perf/python/tracepoint.py b/tools/perf/python/tracepoint.py
new file mode 100755
index 000000000000..eb4dbed57de7
--- /dev/null
+++ b/tools/perf/python/tracepoint.py
@@ -0,0 +1,47 @@
+#! /usr/bin/python
+# -*- python -*-
+# -*- coding: utf-8 -*-
+
+import perf
+
+class tracepoint(perf.evsel):
+ def __init__(self, sys, name):
+ config = perf.tracepoint(sys, name)
+ perf.evsel.__init__(self,
+ type = perf.TYPE_TRACEPOINT,
+ config = config,
+ freq = 0, sample_period = 1, wakeup_events = 1,
+ sample_type = perf.SAMPLE_PERIOD | perf.SAMPLE_TID | perf.SAMPLE_CPU | perf.SAMPLE_RAW | perf.SAMPLE_TIME)
+
+def main():
+ tp = tracepoint("sched", "sched_switch")
+ cpus = perf.cpu_map()
+ threads = perf.thread_map(-1)
+
+ evlist = perf.evlist(cpus, threads)
+ evlist.add(tp)
+ evlist.open()
+ evlist.mmap()
+
+ while True:
+ evlist.poll(timeout = -1)
+ for cpu in cpus:
+ event = evlist.read_on_cpu(cpu)
+ if not event:
+ continue
+
+ if not isinstance(event, perf.sample_event):
+ continue
+
+ print "time %u prev_comm=%s prev_pid=%d prev_prio=%d prev_state=0x%x ==> next_comm=%s next_pid=%d next_prio=%d" % (
+ event.sample_time,
+ event.prev_comm,
+ event.prev_pid,
+ event.prev_prio,
+ event.prev_state,
+ event.next_comm,
+ event.next_pid,
+ event.next_prio)
+
+if __name__ == '__main__':
+ main()
--
2.7.4
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