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| author | Kip Macy <kmacy@FreeBSD.org> | 2007-02-27 06:42:05 +0000 |
|---|---|---|
| committer | Kip Macy <kmacy@FreeBSD.org> | 2007-02-27 06:42:05 +0000 |
| commit | f183910b97a54940f78db43341b3954ba8a2e32d (patch) | |
| tree | c7228dd81a9d5cf5855323c889da39c667a4dd5a /sys/kern/kern_rwlock.c | |
| parent | fc5fe41fe974ad8eb03abb7a1afa6202e678ad7a (diff) | |
| download | src-f183910b97a54940f78db43341b3954ba8a2e32d.tar.gz src-f183910b97a54940f78db43341b3954ba8a2e32d.zip | |
Further improvements to LOCK_PROFILING:
- Fix missing initialization in kern_rwlock.c causing bogus times to be collected
- Move updates to the lock hash to after the lock is released for spin mutexes,
sleep mutexes, and sx locks
- Add new kernel build option LOCK_PROFILE_FAST - only update lock profiling
statistics when an acquisition is contended. This reduces the overhead of
LOCK_PROFILING to increasing system time by 20%-25% which on
"make -j8 kernel-toolchain" on a dual woodcrest is unmeasurable in terms
of wall-clock time. Contrast this to enabling lock profiling without
LOCK_PROFILE_FAST and I see a 5x-6x slowdown in wall-clock time.
Notes
Notes:
svn path=/head/; revision=167054
Diffstat (limited to 'sys/kern/kern_rwlock.c')
| -rw-r--r-- | sys/kern/kern_rwlock.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/sys/kern/kern_rwlock.c b/sys/kern/kern_rwlock.c index 18e9a544153c..9c7d4f8d8875 100644 --- a/sys/kern/kern_rwlock.c +++ b/sys/kern/kern_rwlock.c @@ -150,8 +150,8 @@ _rw_rlock(struct rwlock *rw, const char *file, int line) #ifdef SMP volatile struct thread *owner; #endif - uint64_t waitstart; - int contested; + uint64_t waitstart = 0; + int contested = 0; uintptr_t x; KASSERT(rw_wowner(rw) != curthread, |