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 13from __future__ import print_function 14 15import os, sys 16sys.path.append(os.environ['PERF_EXEC_PATH'] + '/scripts/python/Perf-Trace-Util/lib/Perf/Trace') 17from Util import * 18 19process_names = {} 20thread_thislock = {} 21thread_blocktime = {} 22 23lock_waits = {} # long-lived stats on (tid,lock) blockage elapsed time 24process_names = {} # long-lived pid-to-execname mapping 25 26def 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 36def 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 44def trace_begin(): 45 print("Press control+C to stop and show the summary") 46 47def 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 53