1 # futex contention 2 # (c) 2010, Arnaldo Carvalho de Melo <acme (at] 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 import os, sys 14 sys.path.append(os.environ['PERF_EXEC_PATH'] + '/scripts/python/Perf-Trace-Util/lib/Perf/Trace') 15 from Util import * 16 17 process_names = {} 18 thread_thislock = {} 19 thread_blocktime = {} 20 21 lock_waits = {} # long-lived stats on (tid,lock) blockage elapsed time 22 process_names = {} # long-lived pid-to-execname mapping 23 24 def android_lock(callchain): 25 for c in callchain: 26 if 'sym' in c and 'name' in c['sym']: 27 name = c['sym']['name'] 28 else: 29 continue 30 31 if 'art::Monitor::Lock' in name: 32 return True 33 return False 34 35 def syscalls__sys_enter_futex(event, ctxt, cpu, s, ns, tid, comm, callchain, 36 nr, uaddr, op, val, utime, uaddr2, val3): 37 38 cmd = op & FUTEX_CMD_MASK 39 if cmd != FUTEX_WAIT or android_lock(callchain) == False: 40 return # we don't care about originators of WAKE events 41 # or futex uses that aren't android locks. 42 43 process_names[tid] = comm 44 thread_thislock[tid] = uaddr 45 thread_blocktime[tid] = nsecs(s, ns) 46 47 def syscalls__sys_exit_futex(event, ctxt, cpu, s, ns, tid, comm, callchain, 48 nr, ret): 49 if thread_blocktime.has_key(tid): 50 elapsed = nsecs(s, ns) - thread_blocktime[tid] 51 add_stats(lock_waits, (tid, thread_thislock[tid]), elapsed) 52 del thread_blocktime[tid] 53 del thread_thislock[tid] 54 55 def trace_begin(): 56 print "Press control+C to stop and show the summary" 57 58 def trace_end(): 59 for (tid, lock) in lock_waits: 60 min, max, avg, count = lock_waits[tid, lock] 61 print "%s[%d] lock %x contended %d times, %d avg ns" % \ 62 (process_names[tid], tid, lock, count, avg) 63 64
