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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758# 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
from __future__ import print_function
import osimport syssys.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 timeprocess_names = {} # long-lived pid-to-execname mapping
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: return # we don't care about originators of WAKE events
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 tid in thread_blocktime: 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 [max: %d ns, min %d ns]" % (process_names[tid], tid, lock, count, avg, max, min))