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, sys
  16 sys.path.append(os.environ['PERF_EXEC_PATH'] + '/scripts/python/Perf-Trace-Util/lib/Perf/Trace')
  17 from Util import *
  18
  19 process_names = {}
  20 thread_thislock = {}
  21 thread_blocktime = {}
  22
  23 lock_waits = {} # long-lived stats on (tid,lock) blockage elapsed time
  24 process_names = {} # long-lived pid-to-execname mapping
  25
  26 def syscalls__sys_enter_futex(event, ctxt, cpu, s, ns, tid, comm, callchain,
  27                               nr, uaddr, op, val, utime, uaddr2, val3):
  28         cmd = op & FUTEX_CMD_MASK
  29         if cmd != FUTEX_WAIT:
  30                 return # we don't care about originators of WAKE events
  31
  32         process_names[tid] = comm
  33         thread_thislock[tid] = uaddr
  34         thread_blocktime[tid] = nsecs(s, ns)
  35
  36 def syscalls__sys_exit_futex(event, ctxt, cpu, s, ns, tid, comm, callchain,
  37                              nr, ret):
  38         if tid in thread_blocktime:
  39                 elapsed = nsecs(s, ns) - thread_blocktime[tid]
  40                 add_stats(lock_waits, (tid, thread_thislock[tid]), elapsed)
  41                 del thread_blocktime[tid]
  42                 del thread_thislock[tid]
  43
  44 def trace_begin():
  45         print("Press control+C to stop and show the summary")
  46
  47 def trace_end():
  48         for (tid, lock) in lock_waits:
  49                 min, max, avg, count = lock_waits[tid, lock]
  50                 print("%s[%d] lock %x contended %d times, %d avg ns" %
  51                         (process_names[tid], tid, lock, count, avg))
  52