58 lines · python
1# futex contention2# (c) 2010, Arnaldo Carvalho de Melo <acme@redhat.com>3# Licensed under the terms of the GNU GPL License version 24#5# Translation of:6#7# http://sourceware.org/systemtap/wiki/WSFutexContention8#9# to perf python scripting.10#11# Measures futex contention12 13from __future__ import print_function14 15import os16import sys17sys.path.append(os.environ['PERF_EXEC_PATH'] +18 '/scripts/python/Perf-Trace-Util/lib/Perf/Trace')19from Util import *20 21process_names = {}22thread_thislock = {}23thread_blocktime = {}24 25lock_waits = {} # long-lived stats on (tid,lock) blockage elapsed time26process_names = {} # long-lived pid-to-execname mapping27 28 29def 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_MASK32 if cmd != FUTEX_WAIT:33 return # we don't care about originators of WAKE events34 35 process_names[tid] = comm36 thread_thislock[tid] = uaddr37 thread_blocktime[tid] = nsecs(s, ns)38 39 40def 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 49def trace_begin():50 print("Press control+C to stop and show the summary")51 52 53def 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))58