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Diffstat (limited to 'bcc/misc/futex-contention.py')
-rw-r--r-- | bcc/misc/futex-contention.py | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/bcc/misc/futex-contention.py b/bcc/misc/futex-contention.py new file mode 100644 index 0000000..5c96780 --- /dev/null +++ b/bcc/misc/futex-contention.py @@ -0,0 +1,63 @@ +# futex contention +# (c) 2010, Arnaldo Carvalho de Melo <acme@redhat.com> +# Licensed under the terms of the GNU GPL License version 2 +# +# Translation of: +# +# http://sourceware.org/systemtap/wiki/WSFutexContention +# +# to perf python scripting. +# +# Measures futex contention + +import os, sys +sys.path.append(os.environ['PERF_EXEC_PATH'] + '/scripts/python/Perf-Trace-Util/lib/Perf/Trace') +from Util import * + +process_names = {} +thread_thislock = {} +thread_blocktime = {} + +lock_waits = {} # long-lived stats on (tid,lock) blockage elapsed time +process_names = {} # long-lived pid-to-execname mapping + +def android_lock(callchain): + for c in callchain: + if 'sym' in c and 'name' in c['sym']: + name = c['sym']['name'] + else: + continue + + if 'art::Monitor::Lock' in name: + return True + return False + +def syscalls__sys_enter_futex(event, ctxt, cpu, s, ns, tid, comm, callchain, + nr, uaddr, op, val, utime, uaddr2, val3): + + cmd = op & FUTEX_CMD_MASK + if cmd != FUTEX_WAIT or android_lock(callchain) == False: + return # we don't care about originators of WAKE events + # or futex uses that aren't android locks. + + process_names[tid] = comm + thread_thislock[tid] = uaddr + thread_blocktime[tid] = nsecs(s, ns) + +def syscalls__sys_exit_futex(event, ctxt, cpu, s, ns, tid, comm, callchain, + nr, ret): + if thread_blocktime.has_key(tid): + elapsed = nsecs(s, ns) - thread_blocktime[tid] + add_stats(lock_waits, (tid, thread_thislock[tid]), elapsed) + del thread_blocktime[tid] + del thread_thislock[tid] + +def trace_begin(): + print "Press control+C to stop and show the summary" + +def trace_end(): + for (tid, lock) in lock_waits: + min, max, avg, count = lock_waits[tid, lock] + print "%s[%d] lock %x contended %d times, %d avg ns" % \ + (process_names[tid], tid, lock, count, avg) + |