int block_get_off_bynid(struct block *b,
uint64_t nid,
struct block_pair **bpair)
{
uint32_t i;
int rval = NESS_ERR;
rwlock_read_lock(&b->rwlock, &b->mtx);
for (i = 0; i < b->pairs_used; i++) {
if (b->pairs[i].nid == nid) {
if (b->pairs[i].used) {
*bpair = &b->pairs[i];
rval = NESS_OK;
break;
}
}
}
rwlock_read_unlock(&b->rwlock);
return rval;
}
/** Open a handle to a semaphore.
* @param id ID of the semaphore to open.
* @param rights Access rights for the handle.
* @param handlep Where to store handle to semaphore.
* @return Status code describing result of the operation. */
status_t kern_semaphore_open(semaphore_id_t id, object_rights_t rights, handle_t *handlep) {
user_semaphore_t *sem;
status_t ret;
if(!handlep)
return STATUS_INVALID_ARG;
rwlock_read_lock(&semaphore_tree_lock);
sem = avl_tree_lookup(&semaphore_tree, id);
if(!sem) {
rwlock_unlock(&semaphore_tree_lock);
return STATUS_NOT_FOUND;
}
refcount_inc(&sem->count);
rwlock_unlock(&semaphore_tree_lock);
ret = object_handle_open(&sem->obj, NULL, rights, NULL, 0, NULL, NULL, handlep);
if(ret != STATUS_SUCCESS)
user_semaphore_release(sem);
return ret;
}
int
main(void)
{
uint64_t s_b, e_b, i;
ck_bytelock_t bytelock = CK_BYTELOCK_INITIALIZER;
rwlock_t naive;
for (i = 0; i < STEPS; i++) {
ck_bytelock_write_lock(&bytelock, 1);
ck_bytelock_write_unlock(&bytelock);
}
s_b = rdtsc();
for (i = 0; i < STEPS; i++) {
ck_bytelock_write_lock(&bytelock, 1);
ck_bytelock_write_unlock(&bytelock);
}
e_b = rdtsc();
printf("WRITE: bytelock %15" PRIu64 "\n", (e_b - s_b) / STEPS);
rwlock_init(&naive);
for (i = 0; i < STEPS; i++) {
rwlock_write_lock(&naive);
rwlock_write_unlock(&naive);
}
s_b = rdtsc();
for (i = 0; i < STEPS; i++) {
rwlock_write_lock(&naive);
rwlock_write_unlock(&naive);
}
e_b = rdtsc();
printf("WRITE: naive %15" PRIu64 "\n", (e_b - s_b) / STEPS);
for (i = 0; i < STEPS; i++) {
ck_bytelock_read_lock(&bytelock, 1);
ck_bytelock_read_unlock(&bytelock, 1);
}
s_b = rdtsc();
for (i = 0; i < STEPS; i++) {
ck_bytelock_read_lock(&bytelock, 1);
ck_bytelock_read_unlock(&bytelock, 1);
}
e_b = rdtsc();
printf("READ: bytelock %15" PRIu64 "\n", (e_b - s_b) / STEPS);
for (i = 0; i < STEPS; i++) {
rwlock_read_lock(&naive);
rwlock_read_unlock(&naive);
}
s_b = rdtsc();
for (i = 0; i < STEPS; i++) {
rwlock_read_lock(&naive);
rwlock_read_unlock(&naive);
}
e_b = rdtsc();
printf("READ: naive %15" PRIu64 "\n", (e_b - s_b) / STEPS);
return (0);
}
