Python-bindings: Refactor the Context class
[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 usePID = True
35 else:
36 usePID = 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 while True:
45 if event.get_name() == "sched_switch":
46 # Getting scope definition
47 sco = event.get_top_level_scope(CTFReader.scope.STREAM_EVENT_CONTEXT)
48 if sco is None:
49 print("ERROR: Cannot get definition scope for sched_switch")
50 break # Next event
51
52 # Getting PID
53 pid_field = event.get_field_with_scope(sco, "pid")
54 if pid_field is None:
55 print("ERROR: Missing PID info for sched_switch")
56 break # Next event
57 pid = pid_field.get_value()
58 if usePID and (pid != long(sys.argv[1])):
59 break # Next event
60
61 sco = event.get_top_level_scope(CTFReader.scope.EVENT_FIELDS)
62
63 # prev_comm
64 field = event.get_field_with_scope(sco, "prev_comm")
65 if field is None:
66 print("ERROR: Missing prev_comm context info")
67 prev_comm = field.get_value()
68
69 # prev_tid
70 field = event.get_field_with_scope(sco, "prev_tid")
71 if field is None:
72 print("ERROR: Missing prev_tid context info")
73 prev_tid = field.get_value()
74
75 # prev_prio
76 field = event.get_field_with_scope(sco, "prev_prio")
77 if field is None:
78 print("ERROR: Missing prev_prio context info")
79 prev_prio = field.get_value()
80
81 # prev_state
82 field = event.get_field_with_scope(sco, "prev_state")
83 if field is None:
84 print("ERROR: Missing prev_state context info")
85 prev_state = field.get_value()
86
87 # next_comm
88 field = event.get_field_with_scope(sco, "next_comm")
89 if field is None:
90 print("ERROR: Missing next_comm context info")
91 next_comm = field.get_value()
92
93 # next_tid
94 field = event.get_field_with_scope(sco, "next_tid")
95 if field is None:
96 print("ERROR: Missing next_tid context info")
97 next_tid = field.get_value()
98
99 # next_prio
100 field = event.get_field_with_scope(sco, "next_prio")
101 if field is None:
102 print("ERROR: Missing next_prio context info")
103 next_prio = field.get_value()
104
105 # Output
106 print("sched_switch, pid = {}, TS = {}, prev_comm = {},\n\t"
107 "prev_tid = {}, prev_prio = {}, prev_state = {},\n\t"
108 "next_comm = {}, next_tid = {}, next_prio = {}".format(
109 pid, event.get_timestamp(), prev_comm, prev_tid,
110 prev_prio, prev_state, next_comm, next_tid, next_prio))
111
112 break # Next event
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