Commit Graph

16 Commits

Author SHA1 Message Date
Kris Kennaway
cdcc788a7e Revert some debugging KTRs that were added during development. 2007-06-03 18:24:31 +00:00
John Baldwin
c91fcee75d Move lock_profile_object_{init,destroy}() into lock_{init,destroy}(). 2007-05-18 15:04:59 +00:00
Kip Macy
8289600ce7 skip call to _lock_profile_obtain_lock_success entirely if acquisition time is non-zero
(i.e. recursing or adding sharers)
2007-04-03 18:36:27 +00:00
Kip Macy
fe68a91631 general LOCK_PROFILING cleanup
- only collect timestamps when a lock is contested - this reduces the overhead
  of collecting profiles from 20x to 5x

- remove unused function from subr_lock.c

- generalize cnt_hold and cnt_lock statistics to be kept for all locks

- NOTE: rwlock profiling generates invalid statistics (and most likely always has)
  someone familiar with that should review
2007-02-26 08:26:44 +00:00
Kip Macy
aa077979f6 Bug fix for obscenely large wait times on uncontested locks
if waittime was zero (the lock was uncontested) l->lpo_waittime
in the hash table would not get initialized.

Inspection prompted by questions from: Attilio Rao
2006-12-04 22:15:50 +00:00
Kip Macy
61bd5e21b3 track lock class name in a way that doesn't break WITNESS 2006-11-13 05:41:46 +00:00
Kip Macy
44a96b46bd Unbreak witness 2006-11-12 23:23:38 +00:00
Kip Macy
54e57f7613 show lock class in profiling output for default case where type is not specified when initializing the lock
Approved by: scottl (standing in for mentor rwatson)
2006-11-12 03:30:01 +00:00
Kip Macy
ed6a7c42f6 tinderbox fix 2006-11-11 07:38:48 +00:00
Kip Macy
cf2c39e7a2 remove lingering call to rd(tick) 2006-11-11 07:28:45 +00:00
Kip Macy
83b72e3e25 missed nits replacing mutex with lock 2006-11-11 06:28:47 +00:00
Kip Macy
7c0435b933 MUTEX_PROFILING has been generalized to LOCK_PROFILING. We now profile
wait (time waited to acquire) and hold times for *all* kernel locks. If
the architecture has a system synchronized TSC, the profiling code will
use that - thereby minimizing profiling overhead. Large chunks of profiling
code have been moved out of line, the overhead measured on the T1 for when
it is compiled in but not enabled is < 1%.

Approved by: scottl (standing in for mentor rwatson)
Reviewed by: des and jhb
2006-11-11 03:18:07 +00:00
John Baldwin
3f08bd8bce Add a basic reader/writer lock implementation to the kernel. This
implementation is by no means perfect as far as some of the algorithms
that it uses and the fact that it is missing some functionality (try
locks and upgrades/downgrades are not there yet), however it does seem
to work in my local testing.  There is more detail in the comments in the
code, but the short version follows.

A reader/writer lock is very much like a regular mutex: it cannot be held
across a voluntary sleep; it can be acquired in an interrupt thread; if
the lock is held by a writer then the priority of any threads that block
on the lock will be lent to the owner; the simple case lock operations all
are done in a single atomic op.  It also shares some similiarities
with sx locks: it supports reader/writer semantics (multiple readers,
but single writers); readers are allowed to recurse, but writers are not.

We can extend this implementation further by either improving algorithms
or adding new functionality, but this should at least give us a base to
work with now.

Reviewed by:	arch (in theory)
Tested on:	i386 (4 cpu box with a kernel module that used 4 threads
		that randomly chose between read locks and write locks
		that ran w/o panicing for over a day solid.  It usually
		panic'd within a few seconds when there were bugs during
		testing. :)  The kernel module source is available on
		request.)
2006-01-27 23:13:26 +00:00
John Baldwin
25e498b4b0 Always include the lock_classes[] array in the kernel. The
"is it a spinlock" test in mtx_destroy() needs it even in non-debug
kernels.

Reported by:	danfe
2006-01-18 18:02:50 +00:00
John Baldwin
6ef970a972 Bah. Fix 'show lock' to actually be compiled in. I had just fixed this in
p4 but had an older subr_lock.c on the machine I committed to CVS from.
2006-01-17 16:58:32 +00:00
John Baldwin
83a81bcb14 Add a new file (kern/subr_lock.c) for holding code related to struct
lock_obj objects:
- Add new lock_init() and lock_destroy() functions to setup and teardown
  lock_object objects including KTR logging and registering with WITNESS.
- Move all the handling of LO_INITIALIZED out of witness and the various
  lock init functions into lock_init() and lock_destroy().
- Remove the constants for static indices into the lock_classes[] array
  and change the code outside of subr_lock.c to use LOCK_CLASS to compare
  against a known lock class.
- Move the 'show lock' ddb function and lock_classes[] array out of
  kern_mutex.c over to subr_lock.c.
2006-01-17 16:55:17 +00:00