62 lines
2.5 KiB
Python
62 lines
2.5 KiB
Python
|
#! /usr/bin/python
|
||
|
|
# SPDX-License-Identifier: GPL-2.0-only
|
||
|
|
# -*- python -*-
|
||
|
|
# -*- coding: utf-8 -*-
|
||
|
|
# twatch - Experimental use of the perf python interface
|
||
|
|
# Copyright (C) 2011 Arnaldo Carvalho de Melo <acme@redhat.com>
|
||
|
|
#
|
||
|
|
|
||
|
|
import perf
|
||
|
|
|
||
|
|
def main(context_switch = 0, thread = -1):
|
||
|
|
cpus = perf.cpu_map()
|
||
|
|
threads = perf.thread_map(thread)
|
||
|
|
evsel = perf.evsel(type = perf.TYPE_SOFTWARE,
|
||
|
|
config = perf.COUNT_SW_DUMMY,
|
||
|
|
task = 1, comm = 1, mmap = 0, freq = 0,
|
||
|
|
wakeup_events = 1, watermark = 1,
|
||
|
|
sample_id_all = 1, context_switch = context_switch,
|
||
|
|
sample_type = perf.SAMPLE_PERIOD | perf.SAMPLE_TID | perf.SAMPLE_CPU)
|
||
|
|
|
||
|
|
"""What we want are just the PERF_RECORD_ lifetime events for threads,
|
||
|
|
using the default, PERF_TYPE_HARDWARE + PERF_COUNT_HW_CYCLES & freq=1
|
||
|
|
(the default), makes perf reenable irq_vectors:local_timer_entry, when
|
||
|
|
disabling nohz, not good for some use cases where all we want is to get
|
||
|
|
threads comes and goes... So use (perf.TYPE_SOFTWARE, perf_COUNT_SW_DUMMY,
|
||
|
|
freq=0) instead."""
|
||
|
|
|
||
|
|
evsel.open(cpus = cpus, threads = threads);
|
||
|
|
evlist = perf.evlist(cpus, threads)
|
||
|
|
evlist.add(evsel)
|
||
|
|
evlist.mmap()
|
||
|
|
while True:
|
||
|
|
evlist.poll(timeout = -1)
|
||
|
|
for cpu in cpus:
|
||
|
|
event = evlist.read_on_cpu(cpu)
|
||
|
|
if not event:
|
||
|
|
continue
|
||
|
|
print("cpu: {0}, pid: {1}, tid: {2} {3}".format(event.sample_cpu,
|
||
|
|
event.sample_pid,
|
||
|
|
event.sample_tid,
|
||
|
|
event))
|
||
|
|
|
||
|
|
if __name__ == '__main__':
|
||
|
|
"""
|
||
|
|
To test the PERF_RECORD_SWITCH record, pick a pid and replace
|
||
|
|
in the following line.
|
||
|
|
|
||
|
|
Example output:
|
||
|
|
|
||
|
|
cpu: 3, pid: 31463, tid: 31593 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31593, switch_out: 1 }
|
||
|
|
cpu: 1, pid: 31463, tid: 31489 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31489, switch_out: 1 }
|
||
|
|
cpu: 2, pid: 31463, tid: 31496 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31496, switch_out: 1 }
|
||
|
|
cpu: 3, pid: 31463, tid: 31491 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31491, switch_out: 0 }
|
||
|
|
|
||
|
|
It is possible as well to use event.misc & perf.PERF_RECORD_MISC_SWITCH_OUT
|
||
|
|
to figure out if this is a context switch in or out of the monitored threads.
|
||
|
|
|
||
|
|
If bored, please add command line option parsing support for these options :-)
|
||
|
|
"""
|
||
|
|
# main(context_switch = 1, thread = 31463)
|
||
|
|
main()
|