linux-stable/tools/perf/python/twatch.py
Arnaldo Carvalho de Melo d2ed5d2bdc perf python: Make twatch.py work with both python2 and python3
Will be used to test patches allowing to build perf with python3, so
that we make sure that we can build with both versions.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jaroslav Škarvada <jskarvad@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-c2ynv0ozr3eifzsyit6qgh3h@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-02-19 12:28:08 -03:00

68 lines
2.9 KiB
Python
Executable file

#! /usr/bin/python
# -*- python -*-
# -*- coding: utf-8 -*-
# twatch - Experimental use of the perf python interface
# Copyright (C) 2011 Arnaldo Carvalho de Melo <acme@redhat.com>
#
# This application is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; version 2.
#
# This application is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
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()