# 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 from __future__ import print_function import osimport 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 tid in thread_blocktime:        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 [max: %d ns, min %d ns]" %              (process_names[tid], tid, lock, count, avg, max, min))