Python bindings: sched_switch example clean-up
[babeltrace.git] / bindings / python / examples / sched_switch.py
1 #!/usr/bin/env python3
2 # sched_switch.py
3 #
4 # Babeltrace example script with sched_switch events
5 #
6 # Copyright 2012 EfficiOS Inc.
7 #
8 # Author: Danny Serres <danny.serres@efficios.com>
9 #
10 # Permission is hereby granted, free of charge, to any person obtaining a copy
11 # of this software and associated documentation files (the "Software"), to deal
12 # in the Software without restriction, including without limitation the rights
13 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14 # copies of the Software, and to permit persons to whom the Software is
15 # furnished to do so, subject to the following conditions:
16 #
17 # The above copyright notice and this permission notice shall be included in
18 # all copies or substantial portions of the Software.
19
20 # The script takes one optional argument (pid)
21 # The script will read events based on pid and
22 # print the scheduler switches happening with the process.
23 # If no arguments are passed, it displays all the scheduler switches.
24 # This can be used to understand which tasks schedule out the current
25 # process being traced, and when it gets scheduled in again.
26 # The trace needs PID context (lttng add-context -k -t pid)
27
28 import sys
29 from babeltrace import *
30
31 if len(sys.argv) < 2 or len(sys.argv) > 3:
32 raise TypeError("Usage: python sched_switch.py [pid] path/to/trace")
33 elif len(sys.argv) == 3:
34 filterPID = True
35 else:
36 filterPID = False
37
38 traces = TraceCollection()
39 ret = traces.add_trace(sys.argv[len(sys.argv)-1], "ctf")
40 if ret is None:
41 raise IOError("Error adding trace")
42
43 for event in traces.events:
44 if event.name != "sched_switch":
45 continue
46
47 # Getting PID
48 pid = event.field_with_scope("pid", CTFScope.STREAM_EVENT_CONTEXT)
49 if pid is None:
50 print("ERROR: Missing PID info for sched_switch")
51 continue # Next event
52
53 if filterPID and (pid != long(sys.argv[1])):
54 continue # Next event
55
56 prev_comm = event["prev_comm"]
57 prev_tid = event["prev_tid"]
58 prev_prio = event["prev_prio"]
59 prev_state = event["prev_state"]
60 next_comm = event["next_comm"]
61 next_tid = event["next_tid"]
62 next_prio = event["next_prio"]
63
64 # Output
65 print("sched_switch, pid = {}, TS = {}, prev_comm = {},\n\t"
66 "prev_tid = {}, prev_prio = {}, prev_state = {},\n\t"
67 "next_comm = {}, next_tid = {}, next_prio = {}".format(
68 pid, event.timestamp, prev_comm, prev_tid,
69 prev_prio, prev_state, next_comm, next_tid, next_prio))
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