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877108e4 ACM |
1 | #! /usr/bin/python |
2 | # -*- python -*- | |
3 | # -*- coding: utf-8 -*- | |
4 | # twatch - Experimental use of the perf python interface | |
5 | # Copyright (C) 2011 Arnaldo Carvalho de Melo <acme@redhat.com> | |
6 | # | |
7 | # This application is free software; you can redistribute it and/or | |
8 | # modify it under the terms of the GNU General Public License | |
9 | # as published by the Free Software Foundation; version 2. | |
10 | # | |
11 | # This application is distributed in the hope that it will be useful, | |
12 | # but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | # General Public License for more details. | |
15 | ||
16 | import perf | |
17 | ||
ae938802 | 18 | def main(context_switch = 0, thread = -1): |
877108e4 | 19 | cpus = perf.cpu_map() |
ae938802 | 20 | threads = perf.thread_map(thread) |
58b32c1b ACM |
21 | evsel = perf.evsel(type = perf.TYPE_SOFTWARE, |
22 | config = perf.COUNT_SW_DUMMY, | |
23 | task = 1, comm = 1, mmap = 0, freq = 0, | |
cfeb1d90 | 24 | wakeup_events = 1, watermark = 1, |
ae938802 | 25 | sample_id_all = 1, context_switch = context_switch, |
3223565c | 26 | sample_type = perf.SAMPLE_PERIOD | perf.SAMPLE_TID | perf.SAMPLE_CPU) |
58b32c1b ACM |
27 | |
28 | """What we want are just the PERF_RECORD_ lifetime events for threads, | |
29 | using the default, PERF_TYPE_HARDWARE + PERF_COUNT_HW_CYCLES & freq=1 | |
30 | (the default), makes perf reenable irq_vectors:local_timer_entry, when | |
31 | disabling nohz, not good for some use cases where all we want is to get | |
32 | threads comes and goes... So use (perf.TYPE_SOFTWARE, perf_COUNT_SW_DUMMY, | |
33 | freq=0) instead.""" | |
34 | ||
877108e4 | 35 | evsel.open(cpus = cpus, threads = threads); |
7e2ed097 | 36 | evlist = perf.evlist(cpus, threads) |
877108e4 | 37 | evlist.add(evsel) |
7e2ed097 | 38 | evlist.mmap() |
877108e4 ACM |
39 | while True: |
40 | evlist.poll(timeout = -1) | |
41 | for cpu in cpus: | |
42 | event = evlist.read_on_cpu(cpu) | |
43 | if not event: | |
44 | continue | |
45 | print "cpu: %2d, pid: %4d, tid: %4d" % (event.sample_cpu, | |
46 | event.sample_pid, | |
47 | event.sample_tid), | |
48 | print event | |
49 | ||
50 | if __name__ == '__main__': | |
ae938802 ACM |
51 | """ |
52 | To test the PERF_RECORD_SWITCH record, pick a pid and replace | |
53 | in the following line. | |
54 | ||
55 | Example output: | |
56 | ||
57 | cpu: 3, pid: 31463, tid: 31593 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31593, switch_out: 1 } | |
58 | cpu: 1, pid: 31463, tid: 31489 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31489, switch_out: 1 } | |
59 | cpu: 2, pid: 31463, tid: 31496 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31496, switch_out: 1 } | |
60 | cpu: 3, pid: 31463, tid: 31491 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31491, switch_out: 0 } | |
61 | ||
62 | It is possible as well to use event.misc & perf.PERF_RECORD_MISC_SWITCH_OUT | |
63 | to figure out if this is a context switch in or out of the monitored threads. | |
64 | ||
65 | If bored, please add command line option parsing support for these options :-) | |
66 | """ | |
67 | # main(context_switch = 1, thread = 31463) | |
877108e4 | 68 | main() |