static inline void
decrementcounter(isc_stats_t *stats, int counter) {
isc_int32_t prev;
#ifdef ISC_RWLOCK_USEATOMIC
isc_rwlock_lock(&stats->counterlock, isc_rwlocktype_read);
#endif
#if ISC_STATS_USEMULTIFIELDS
prev = isc_atomic_xadd((isc_int32_t *)&stats->counters[counter].lo, -1);
if (prev == 0)
isc_atomic_xadd((isc_int32_t *)&stats->counters[counter].hi,
-1);
#elif defined(ISC_PLATFORM_HAVEXADDQ)
UNUSED(prev);
isc_atomic_xaddq((isc_int64_t *)&stats->counters[counter], -1);
#else
UNUSED(prev);
stats->counters[counter]--;
#endif
#ifdef ISC_RWLOCK_USEATOMIC
isc_rwlock_unlock(&stats->counterlock, isc_rwlocktype_read);
#endif
}
void
do_xaddq(isc_task_t *task, isc_event_t *ev) {
counter_t *state = (counter_t *)ev->ev_arg;
int i;
for (i = 0 ; i < COUNTS_PER_ITERATION ; i++) {
isc_atomic_xaddq(&counter_64, INCREMENT_64);
}
state->iteration++;
if (state->iteration < ITERATIONS) {
isc_task_send(task, &ev);
} else {
isc_event_free(&ev);
}
}
static inline void
incrementcounter(isc_stats_t *stats, int counter) {
isc_int32_t prev;
#ifdef ISC_RWLOCK_USEATOMIC
/*
* We use a "read" lock to prevent other threads from reading the
* counter while we "writing" a counter field. The write access itself
* is protected by the atomic operation.
*/
isc_rwlock_lock(&stats->counterlock, isc_rwlocktype_read);
#endif
#if ISC_STATS_USEMULTIFIELDS
prev = isc_atomic_xadd((isc_int32_t *)&stats->counters[counter].lo, 1);
/*
* If the lower 32-bit field overflows, increment the higher field.
* Note that it's *theoretically* possible that the lower field
* overlaps again before the higher field is incremented. It doesn't
* matter, however, because we don't read the value until
* isc_stats_copy() is called where the whole process is protected
* by the write (exclusive) lock.
*/
if (prev == (isc_int32_t)0xffffffff)
isc_atomic_xadd((isc_int32_t *)&stats->counters[counter].hi, 1);
#elif defined(ISC_PLATFORM_HAVEXADDQ)
UNUSED(prev);
isc_atomic_xaddq((isc_int64_t *)&stats->counters[counter], 1);
#else
UNUSED(prev);
stats->counters[counter]++;
#endif
#ifdef ISC_RWLOCK_USEATOMIC
isc_rwlock_unlock(&stats->counterlock, isc_rwlocktype_read);
#endif
}
