Commit Graph

6 Commits

Author SHA1 Message Date
Mark Johnston
de2c95cc00 Consistently use a reader/writer flag for lockstat probes in rwlock(9) and
sx(9), rather than using the probe function name to determine whether a
given lock is a read lock or a write lock. Update lockstat(1) accordingly.
2015-07-19 22:24:33 +00:00
Mark Johnston
32cd0147fa Implement the lockstat provider using SDT(9) instead of the custom provider
in lockstat.ko. This means that lockstat probes now have typed arguments and
will utilize SDT probe hot-patching support when it arrives.

Reviewed by:	gnn
Differential Revision:	https://reviews.freebsd.org/D2993
2015-07-19 22:14:09 +00:00
Mark Johnston
e2b25737ee Pass the lock object to lockstat_nsecs() and return immediately if
LO_NOPROFILE is set. Some timecounter handlers acquire a spin mutex, and
we don't want to recurse if lockstat probes are enabled.

PR:		201642
Reviewed by:	avg
MFC after:	3 days
2015-07-18 00:57:30 +00:00
Mark Johnston
efe8b26b82 Modify lockstat_nsecs() to just return unless lockstat probes are actually
enabled. The cost of a timecounter read can be quite significant, and the
problem became more apparent after r284297, since that change resulted in
a call to lockstat_nsecs() for each acquisition of an rwlock read lock.

PR:		201642
Reviewed by:	avg
Tested by:	Jason Unovitch
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D3073
2015-07-18 00:22:00 +00:00
Attilio Rao
54366c0bd7 - For kernel compiled only with KDTRACE_HOOKS and not any lock debugging
option, unbreak the lock tracing release semantic by embedding
  calls to LOCKSTAT_PROFILE_RELEASE_LOCK() direclty in the inlined
  version of the releasing functions for mutex, rwlock and sxlock.
  Failing to do so skips the lockstat_probe_func invokation for
  unlocking.
- As part of the LOCKSTAT support is inlined in mutex operation, for
  kernel compiled without lock debugging options, potentially every
  consumer must be compiled including opt_kdtrace.h.
  Fix this by moving KDTRACE_HOOKS into opt_global.h and remove the
  dependency by opt_kdtrace.h for all files, as now only KDTRACE_FRAMES
  is linked there and it is only used as a compile-time stub [0].

[0] immediately shows some new bug as DTRACE-derived support for debug
in sfxge is broken and it was never really tested.  As it was not
including correctly opt_kdtrace.h before it was never enabled so it
was kept broken for a while.  Fix this by using a protection stub,
leaving sfxge driver authors the responsibility for fixing it
appropriately [1].

Sponsored by:	EMC / Isilon storage division
Discussed with:	rstone
[0] Reported by:	rstone
[1] Discussed with:	philip
2013-11-25 07:38:45 +00:00
Stacey Son
a5aedd68b4 Add the OpenSolaris dtrace lockstat provider. The lockstat provider
adds probes for mutexes, reader/writer and shared/exclusive locks to
gather contention statistics and other locking information for
dtrace scripts, the lockstat(1M) command and other potential
consumers.

Reviewed by:	attilio jhb jb
Approved by:	gnn (mentor)
2009-05-26 20:28:22 +00:00