#! /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():	cpus = perf.cpu_map()	threads = perf.thread_map()	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,			   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: %2d, pid: %4d, tid: %4d" % (event.sample_cpu,								event.sample_pid,								event.sample_tid),			print event if __name__ == '__main__':    main()