| 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 | |
| 39 | ctx = Context() |
| 40 | ret = ctx.add_trace(sys.argv[len(sys.argv)-1], "ctf") |
| 41 | if ret is None: |
| 42 | raise IOError("Error adding trace") |
| 43 | |
| 44 | # Setting iterator |
| 45 | bp = IterPos(SEEK_BEGIN) |
| 46 | ctf_it = ctf.Iterator(ctx, bp) |
| 47 | |
| 48 | # Reading events |
| 49 | event = ctf_it.read_event() |
| 50 | while event is not None: |
| 51 | while True: |
| 52 | if event.get_name() == "sched_switch": |
| 53 | # Getting scope definition |
| 54 | sco = event.get_top_level_scope(ctf.scope.STREAM_EVENT_CONTEXT) |
| 55 | if sco is None: |
| 56 | print("ERROR: Cannot get definition scope for sched_switch") |
| 57 | break # Next event |
| 58 | |
| 59 | # Getting PID |
| 60 | pid_field = event.get_field_with_scope(sco, "_pid") |
| 61 | pid = pid_field.get_int64() |
| 62 | |
| 63 | if ctf.field_error(): |
| 64 | print("ERROR: Missing PID info for sched_switch") |
| 65 | break # Next event |
| 66 | |
| 67 | if usePID and (pid != long(sys.argv[1])): |
| 68 | break # Next event |
| 69 | |
| 70 | sco = event.get_top_level_scope(ctf.scope.EVENT_FIELDS) |
| 71 | |
| 72 | # prev_comm |
| 73 | field = event.get_field_with_scope(sco, "_prev_comm") |
| 74 | prev_comm = field.get_char_array() |
| 75 | if ctf.field_error(): |
| 76 | print("ERROR: Missing prev_comm context info") |
| 77 | |
| 78 | # prev_tid |
| 79 | field = event.get_field_with_scope(sco, "_prev_tid") |
| 80 | prev_tid = field.get_int64() |
| 81 | if ctf.field_error(): |
| 82 | print("ERROR: Missing prev_tid context info") |
| 83 | |
| 84 | # prev_prio |
| 85 | field = event.get_field_with_scope(sco, "_prev_prio") |
| 86 | prev_prio = field.get_int64() |
| 87 | if ctf.field_error(): |
| 88 | print("ERROR: Missing prev_prio context info") |
| 89 | |
| 90 | # prev_state |
| 91 | field = event.get_field_with_scope(sco, "_prev_state") |
| 92 | prev_state = field.get_int64() |
| 93 | if ctf.field_error(): |
| 94 | print("ERROR: Missing prev_state context info") |
| 95 | |
| 96 | # next_comm |
| 97 | field = event.get_field_with_scope(sco, "_next_comm") |
| 98 | next_comm = field.get_char_array() |
| 99 | if ctf.field_error(): |
| 100 | print("ERROR: Missing next_comm context info") |
| 101 | |
| 102 | # next_tid |
| 103 | field = event.get_field_with_scope(sco, "_next_tid") |
| 104 | next_tid = field.get_int64() |
| 105 | if ctf.field_error(): |
| 106 | print("ERROR: Missing next_tid context info") |
| 107 | |
| 108 | # next_prio |
| 109 | field = event.get_field_with_scope(sco, "_next_prio") |
| 110 | next_prio = field.get_int64() |
| 111 | if ctf.field_error(): |
| 112 | print("ERROR: Missing next_prio context info") |
| 113 | |
| 114 | # Output |
| 115 | print("sched_switch, pid = {}, TS = {}, prev_comm = {},\n\t" |
| 116 | "prev_tid = {}, prev_prio = {}, prev_state = {},\n\t" |
| 117 | "next_comm = {}, next_tid = {}, next_prio = {}".format( |
| 118 | pid, event.get_timestamp(), prev_comm, prev_tid, |
| 119 | prev_prio, prev_state, next_comm, next_tid, next_prio)) |
| 120 | |
| 121 | break # Next event |
| 122 | |
| 123 | # Next event |
| 124 | ret = ctf_it.next() |
| 125 | if ret < 0: |
| 126 | break |
| 127 | event = ctf_it.read_event() |
| 128 | |
| 129 | del ctf_it |