1#! /usr/bin/env python
2# SPDX-License-Identifier: GPL-2.0
3# -*- python -*-
4# -*- coding: utf-8 -*-
5
6import perf
7
8class tracepoint(perf.evsel):
9    def __init__(self, sys, name):
10        config = perf.tracepoint(sys, name)
11        perf.evsel.__init__(self,
12                            type   = perf.TYPE_TRACEPOINT,
13                            config = config,
14                            freq = 0, sample_period = 1, wakeup_events = 1,
15                            sample_type = perf.SAMPLE_PERIOD | perf.SAMPLE_TID | perf.SAMPLE_CPU | perf.SAMPLE_RAW | perf.SAMPLE_TIME)
16
17def main():
18    tp      = tracepoint("sched", "sched_switch")
19    cpus    = perf.cpu_map()
20    threads = perf.thread_map(-1)
21
22    evlist = perf.evlist(cpus, threads)
23    evlist.add(tp)
24    evlist.open()
25    evlist.mmap()
26
27    while True:
28        evlist.poll(timeout = -1)
29        for cpu in cpus:
30            event = evlist.read_on_cpu(cpu)
31            if not event:
32                continue
33
34            if not isinstance(event, perf.sample_event):
35                continue
36
37            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" % (
38                   event.sample_time,
39                   event.prev_comm,
40                   event.prev_pid,
41                   event.prev_prio,
42                   event.prev_state,
43                   event.next_comm,
44                   event.next_pid,
45                   event.next_prio))
46
47if __name__ == '__main__':
48    main()
49