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 13import os, sys 14sys.path.append(os.environ['PERF_EXEC_PATH'] + '/scripts/python/Perf-Trace-Util/lib/Perf/Trace') 15from Util import * 16 17process_names = {} 18thread_thislock = {} 19thread_blocktime = {} 20 21lock_waits = {} # long-lived stats on (tid,lock) blockage elapsed time 22process_names = {} # long-lived pid-to-execname mapping 23 24def syscalls__sys_enter_futex(event, ctxt, cpu, s, ns, tid, comm, callchain, 25 nr, uaddr, op, val, utime, uaddr2, val3): 26 cmd = op & FUTEX_CMD_MASK 27 if cmd != FUTEX_WAIT: 28 return # we don't care about originators of WAKE events 29 30 process_names[tid] = comm 31 thread_thislock[tid] = uaddr 32 thread_blocktime[tid] = nsecs(s, ns) 33 34def syscalls__sys_exit_futex(event, ctxt, cpu, s, ns, tid, comm, callchain, 35 nr, ret): 36 if thread_blocktime.has_key(tid): 37 elapsed = nsecs(s, ns) - thread_blocktime[tid] 38 add_stats(lock_waits, (tid, thread_thislock[tid]), elapsed) 39 del thread_blocktime[tid] 40 del thread_thislock[tid] 41 42def trace_begin(): 43 print "Press control+C to stop and show the summary" 44 45def trace_end(): 46 for (tid, lock) in lock_waits: 47 min, max, avg, count = lock_waits[tid, lock] 48 print "%s[%d] lock %x contended %d times, %d avg ns" % \ 49 (process_names[tid], tid, lock, count, avg) 50 51