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When LWLOCK_STATS is defined, count spindelays.

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When LWLOCK_STATS is *not* defined, the only change is that
SpinLockAcquire now returns the number of delays.

Patch by me, review by Jeff Janes.
This commit is contained in:
Robert Haas 2012-06-26 16:02:55 -04:00
parent 757773602c
commit b79ab00144
3 changed files with 15 additions and 10 deletions
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12
src/backend/storage/lmgr/lwlock.c
View File

@ -95,6 +95,7 @@ static int counts_for_pid = 0;
static int *sh_acquire_counts;
static int *ex_acquire_counts;
static int *block_counts;
static int *spin_delay_counts;
#endif
#ifdef LOCK_DEBUG
@ -134,6 +135,7 @@ init_lwlock_stats(void)
sh_acquire_counts = calloc(numLocks, sizeof(int));
ex_acquire_counts = calloc(numLocks, sizeof(int));
spin_delay_counts = calloc(numLocks, sizeof(int));
block_counts = calloc(numLocks, sizeof(int));
counts_for_pid = MyProcPid;
on_shmem_exit(print_lwlock_stats, 0);
@ -151,10 +153,10 @@ print_lwlock_stats(int code, Datum arg)
for (i = 0; i < numLocks; i++)
{
if (sh_acquire_counts[i] || ex_acquire_counts[i] || block_counts[i])
fprintf(stderr, "PID %d lwlock %d: shacq %u exacq %u blk %u\n",
if (sh_acquire_counts[i] || ex_acquire_counts[i] || block_counts[i] || spin_delay_counts[i])
fprintf(stderr, "PID %d lwlock %d: shacq %u exacq %u blk %u spindelay %u\n",
MyProcPid, i, sh_acquire_counts[i], ex_acquire_counts[i],
block_counts[i]);
block_counts[i], spin_delay_counts[i]);
}
LWLockRelease(0);
@ -395,7 +397,11 @@ LWLockAcquire(LWLockId lockid, LWLockMode mode)
bool mustwait;
/* Acquire mutex. Time spent holding mutex should be short! */
#ifdef LWLOCK_STATS
spin_delay_counts[lockid] += SpinLockAcquire(&lock->mutex);
#else
SpinLockAcquire(&lock->mutex);
#endif
/* If retrying, allow LWLockRelease to release waiters again */
if (retry)

3
src/backend/storage/lmgr/s_lock.c
View File

@ -46,7 +46,7 @@ s_lock_stuck(volatile slock_t *lock, const char *file, int line)
/*
* s_lock(lock) - platform-independent portion of waiting for a spinlock.
*/
void
int
s_lock(volatile slock_t *lock, const char *file, int line)
{
/*
@ -155,6 +155,7 @@ s_lock(volatile slock_t *lock, const char *file, int line)
if (spins_per_delay > MIN_SPINS_PER_DELAY)
spins_per_delay = Max(spins_per_delay - 1, MIN_SPINS_PER_DELAY);
}
return delays;
}

10
src/include/storage/s_lock.h
View File

@ -12,10 +12,11 @@
* void S_INIT_LOCK(slock_t *lock)
* Initialize a spinlock (to the unlocked state).
*
* void S_LOCK(slock_t *lock)
* int S_LOCK(slock_t *lock)
* Acquire a spinlock, waiting if necessary.
* Time out and abort() if unable to acquire the lock in a
* "reasonable" amount of time --- typically ~ 1 minute.
* Should return number of "delays"; see s_lock.c
*
* void S_UNLOCK(slock_t *lock)
* Unlock a previously acquired lock.
@ -978,10 +979,7 @@ extern int tas_sema(volatile slock_t *lock);
#if !defined(S_LOCK)
#define S_LOCK(lock) \
do { \
if (TAS(lock)) \
s_lock((lock), __FILE__, __LINE__); \
} while (0)
(TAS(lock) ? s_lock((lock), __FILE__, __LINE__) : 0)
#endif /* S_LOCK */
#if !defined(S_LOCK_FREE)
@ -1015,7 +1013,7 @@ extern int tas(volatile slock_t *lock); /* in port/.../tas.s, or
/*
* Platform-independent out-of-line support routines
*/
extern void s_lock(volatile slock_t *lock, const char *file, int line);
extern int s_lock(volatile slock_t *lock, const char *file, int line);
/* Support for dynamic adjustment of spins_per_delay */
#define DEFAULT_SPINS_PER_DELAY 100