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freebsd/sys/compat/linux/trace_futexes.d
Alexander Leidinger 19e252baeb - >500 static DTrace probes for the linuxulator
- DTrace scripts to check for errors, performance, ...
  they serve mostly as examples of what you can do with the static probe;s
  with moderate load the scripts may be overwhelmed, excessive lock-tracing
  may influence program behavior (see the last design decission)

Design decissions:
 - use "linuxulator" as the provider for the native bitsize; add the
   bitsize for the non-native emulation (e.g. "linuxuator32" on amd64)
 - Add probes only for locks which are acquired in one function and released
   in another function. Locks which are aquired and released in the same
   function should be easy to pair in the code, inter-function
   locking is more easy to verify in DTrace.
 - Probes for locks should be fired after locking and before releasing to
   prevent races (to provide data/function stability in DTrace, see the
   man-page of "dtrace -v ..." and the corresponding DTrace docs).
2012-05-05 19:42:38 +00:00

183 lines
5.5 KiB
D

#!/usr/sbin/dtrace -qs
/*-
* Copyright (c) 2011-2012 Alexander Leidinger <netchild@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
/**
* Trace futex operations:
* - internal locks
* - size of the futex list
* - report error conditions (emulation errors, kernel errors,
* programming errors)
* - execution time (wallclock) of futex related functions
*/
#pragma D option specsize=32m
/* Error conditions */
linuxulator*:futex:futex_get:error,
linuxulator*:futex:futex_sleep:requeue_error,
linuxulator*:futex:futex_sleep:sleep_error,
linuxulator*:futex:futex_wait:copyin_error,
linuxulator*:futex:futex_wait:itimerfix_error,
linuxulator*:futex:futex_wait:sleep_error,
linuxulator*:futex:futex_atomic_op:missing_access_check,
linuxulator*:futex:futex_atomic_op:unimplemented_op,
linuxulator*:futex:futex_atomic_op:unimplemented_cmp,
linuxulator*:futex:linux_sys_futex:unimplemented_clockswitch,
linuxulator*:futex:linux_sys_futex:copyin_error,
linuxulator*:futex:linux_sys_futex:unhandled_efault,
linuxulator*:futex:linux_sys_futex:unimplemented_lock_pi,
linuxulator*:futex:linux_sys_futex:unimplemented_unlock_pi,
linuxulator*:futex:linux_sys_futex:unimplemented_trylock_pi,
linuxulator*:futex:linux_sys_futex:unimplemented_wait_requeue_pi,
linuxulator*:futex:linux_sys_futex:unimplemented_cmp_requeue_pi,
linuxulator*:futex:linux_sys_futex:unknown_operation,
linuxulator*:futex:linux_get_robust_list:copyout_error,
linuxulator*:futex:handle_futex_death:copyin_error,
linuxulator*:futex:fetch_robust_entry:copyin_error,
linuxulator*:futex:release_futexes:copyin_error
{
printf("ERROR: %s in %s:%s:%s\n", probename, probeprov, probemod,
probefunc);
stack();
ustack();
}
linuxulator*:futex:linux_sys_futex:invalid_cmp_requeue_use,
linuxulator*:futex:linux_sys_futex:deprecated_requeue,
linuxulator*:futex:linux_set_robust_list:size_error
{
printf("WARNING: %s:%s:%s:%s in application %s, maybe an application error?\n",
probename, probeprov, probemod, probefunc, execname);
stack();
ustack();
}
/* Per futex checks/statistics */
linuxulator*:futex:futex:create
{
++futex_count;
@max_futexes = max(futex_count);
}
linuxulator*:futex:futex:destroy
/futex_count == 0/
{
printf("ERROR: Request to destroy a futex which was not created,\n");
printf(" or this script was started after some futexes where\n");
printf(" created. Stack trace:\n");
stack();
ustack();
}
linuxulator*:futex:futex:destroy
{
--futex_count;
}
/* Internal locks */
linuxulator*:locks:futex_mtx:locked
{
++check[probefunc, arg0];
@stats[probefunc] = count();
ts[probefunc] = timestamp;
spec[probefunc] = speculation();
printf("Stacktrace of last lock operation of the %s:\n", probefunc);
stack();
}
linuxulator*:locks:futex_mtx:unlock
/check[probefunc, arg0] == 0/
{
printf("ERROR: unlock attemt of unlocked %s (%p),", probefunc, arg0);
printf(" missing SDT probe in kernel, or dtrace program started");
printf(" while the %s was already held (race condition).", probefunc);
printf(" Stack trace follows:");
stack();
}
linuxulator*:locks:futex_mtx:unlock
{
discard(spec[probefunc]);
spec[probefunc] = 0;
--check[probefunc, arg0];
}
/* Timeout handling for internal locks */
tick-10s
/spec["futex_mtx"] != 0 && timestamp - ts["futex_mtx"] >= 9999999000/
{
commit(spec["futex_mtx"]);
spec["futex_mtx"] = 0;
}
/* Timing statistings */
linuxulator*:futex::entry
{
self->time[probefunc] = timestamp;
@calls[probeprov, execname, probefunc] = count();
}
linuxulator*:futex::return
/self->time[probefunc] != 0/
{
this->timediff = self->time[probefunc] - timestamp;
@timestats[probeprov, execname, probefunc] = quantize(this->timediff);
@longest[probeprov, probefunc] = max(this->timediff);
self->time[probefunc] = 0;
}
/* Statistics */
END
{
printf("Number of locks per type:");
printa(@stats);
printf("Number of maximum number of futexes in the futex list:");
printa(@max_futexes);
printf("Number of futexes still existing: %d", futex_count);
printf("Number of calls per provider/application/kernel function:");
printa(@calls);
printf("Wallclock-timing statistics per provider/application/kernel function (in ns):");
printa(@timestats);
printf("Longest running (wallclock!) functions per provider (in ns):");
printa(@longest);
}