tools/perf/scripts/python/futex-contention.py

   1 # futex contention
   2 # (c) 2010, Arnaldo Carvalho de Melo <acme@redhat.com>
   3 # Licensed under the terms of the GNU GPL License version 2
   4 #
   5 # Translation of:
   6 #
   7 # http://sourceware.org/systemtap/wiki/WSFutexContention
   8 #
   9 # to perf python scripting.
  10 #
  11 # Measures futex contention
  12
  13 from __future__ import print_function
  14
  15 import os
  16 import sys
  17 sys.path.append(os.environ['PERF_EXEC_PATH'] +
  18                 '/scripts/python/Perf-Trace-Util/lib/Perf/Trace')
  19 from Util import *
  20
  21 process_names = {}
  22 thread_thislock = {}
  23 thread_blocktime = {}
  24
  25 lock_waits = {}  # long-lived stats on (tid,lock) blockage elapsed time
  26 process_names = {}  # long-lived pid-to-execname mapping
  27
  28
  29 def syscalls__sys_enter_futex(event, ctxt, cpu, s, ns, tid, comm, callchain,
  30                               nr, uaddr, op, val, utime, uaddr2, val3):
  31     cmd = op & FUTEX_CMD_MASK
  32     if cmd != FUTEX_WAIT:
  33         return  # we don't care about originators of WAKE events
  34
  35     process_names[tid] = comm
  36     thread_thislock[tid] = uaddr
  37     thread_blocktime[tid] = nsecs(s, ns)
  38
  39
  40 def syscalls__sys_exit_futex(event, ctxt, cpu, s, ns, tid, comm, callchain,
  41                              nr, ret):
  42     if tid in thread_blocktime:
  43         elapsed = nsecs(s, ns) - thread_blocktime[tid]
  44         add_stats(lock_waits, (tid, thread_thislock[tid]), elapsed)
  45         del thread_blocktime[tid]
  46         del thread_thislock[tid]
  47
  48
  49 def trace_begin():
  50     print("Press control+C to stop and show the summary")
  51
  52
  53 def trace_end():
  54     for (tid, lock) in lock_waits:
  55         min, max, avg, count = lock_waits[tid, lock]
  56         print("%s[%d] lock %x contended %d times, %d avg ns [max: %d ns, min %d ns]" %
  57               (process_names[tid], tid, lock, count, avg, max, min))