forked from Minki/linux
58b32c1b53
To not sample, what we want are just the PERF_RECORD_ lifetime events for threads, using the default, PERF_TYPE_HARDWARE + PERF_COUNT_HW_CYCLES and freq=1 (the default), makes perf reenable irq_vectors:local_timer_entry, disabling nohz, not good for some use cases where all we want is to get notifications when threads comes and goes... Fix it by using PERF_TYPE_SOFTWARE (no counter rotation) and PERF_COUNT_SW_DUMMY (created by Adrian so that we could have access to those PERF_RECORD_ goodies). Reported-by: Luiz Fernando Capitulino <lcapitulino@redhat.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jaroslav Skarvada <jskarvad@redhat.com> Cc: Jeremy Eder <jeder@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-kfsijirfrs6xfhkcdxeoen06@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
52 lines
1.7 KiB
Python
Executable File
52 lines
1.7 KiB
Python
Executable File
#! /usr/bin/python
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# -*- python -*-
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# -*- coding: utf-8 -*-
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# twatch - Experimental use of the perf python interface
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# Copyright (C) 2011 Arnaldo Carvalho de Melo <acme@redhat.com>
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#
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# This application is free software; you can redistribute it and/or
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# modify it under the terms of the GNU General Public License
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# as published by the Free Software Foundation; version 2.
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#
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# This application is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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import perf
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def main():
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cpus = perf.cpu_map()
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threads = perf.thread_map()
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evsel = perf.evsel(type = perf.TYPE_SOFTWARE,
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config = perf.COUNT_SW_DUMMY,
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task = 1, comm = 1, mmap = 0, freq = 0,
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wakeup_events = 1, watermark = 1,
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sample_id_all = 1,
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sample_type = perf.SAMPLE_PERIOD | perf.SAMPLE_TID | perf.SAMPLE_CPU)
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"""What we want are just the PERF_RECORD_ lifetime events for threads,
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using the default, PERF_TYPE_HARDWARE + PERF_COUNT_HW_CYCLES & freq=1
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(the default), makes perf reenable irq_vectors:local_timer_entry, when
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disabling nohz, not good for some use cases where all we want is to get
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threads comes and goes... So use (perf.TYPE_SOFTWARE, perf_COUNT_SW_DUMMY,
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freq=0) instead."""
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evsel.open(cpus = cpus, threads = threads);
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evlist = perf.evlist(cpus, threads)
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evlist.add(evsel)
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evlist.mmap()
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while True:
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evlist.poll(timeout = -1)
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for cpu in cpus:
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event = evlist.read_on_cpu(cpu)
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if not event:
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continue
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print "cpu: %2d, pid: %4d, tid: %4d" % (event.sample_cpu,
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event.sample_pid,
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event.sample_tid),
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print event
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if __name__ == '__main__':
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main()
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