# futex contention# (c) 2010, Arnaldo Carvalho de Melo <acme@redhat.com># Licensed under the terms of the GNU GPL License version 2## Translation of:## http://sourceware.org/systemtap/wiki/WSFutexContention## to perf python scripting.## Measures futex contention import os, syssys.path.append(os.environ['PERF_EXEC_PATH'] + '/scripts/python/Perf-Trace-Util/lib/Perf/Trace')from Util import * process_names = {}thread_thislock = {}thread_blocktime = {} lock_waits = {} # long-lived stats on (tid,lock) blockage elapsed timeprocess_names = {} # long-lived pid-to-execname mapping def syscalls__sys_enter_futex(event, ctxt, cpu, s, ns, tid, comm, callchain,			      nr, uaddr, op, val, utime, uaddr2, val3):	cmd = op & FUTEX_CMD_MASK	if cmd != FUTEX_WAIT:		return # we don't care about originators of WAKE events 	process_names[tid] = comm	thread_thislock[tid] = uaddr	thread_blocktime[tid] = nsecs(s, ns) def syscalls__sys_exit_futex(event, ctxt, cpu, s, ns, tid, comm, callchain,			     nr, ret):	if thread_blocktime.has_key(tid):		elapsed = nsecs(s, ns) - thread_blocktime[tid]		add_stats(lock_waits, (tid, thread_thislock[tid]), elapsed)		del thread_blocktime[tid]		del thread_thislock[tid] def trace_begin():	print "Press control+C to stop and show the summary" def trace_end():	for (tid, lock) in lock_waits:		min, max, avg, count = lock_waits[tid, lock]		print "%s[%d] lock %x contended %d times, %d avg ns" % \		      (process_names[tid], tid, lock, count, avg)