int ticketepfl_mutex_lock(ticketepfl_mutex_t *impl,
ticketepfl_context_t *UNUSED(me)) {
// Acquire the local lock
uint32_t my_ticket = __sync_add_and_fetch(&impl->u.s.request, 1);
uint32_t wait = TICKET_BASE_WAIT;
uint32_t distance_prev = 1;
while (1) {
PREFETCHW(&impl->u.u);
uint32_t cur = impl->u.s.grant;
if (cur == my_ticket) {
break;
}
uint32_t distance = sub_abs(cur, my_ticket);
if (distance > 1) {
if (distance != distance_prev) {
distance_prev = distance;
wait = TICKET_BASE_WAIT;
}
nop_rep(distance * wait);
/* wait = (wait + TICKET_BASE_WAIT) & TICKET_MAX_WAIT; */
} else {
nop_rep(TICKET_WAIT_NEXT);
}
if (distance > 20) {
sched_yield();
/* pthread_yield(); */
}
}
#if COND_VAR
int ret = REAL(pthread_mutex_lock)(&impl->posix_lock);
assert(ret == 0);
#endif
return 0;
}
/*
* Function optimistic_delete is similar to the method remove of the paper.
* Here we avoid the fast search parameter as the comparison is faster in C
* than calling the Java compareTo method of the Comparable interface
* (cf. p132 of SIROCCO'07 proceedings).
*/
sval_t
optimistic_delete(sl_intset_t *set, skey_t key)
{
sl_node_t *succs[HERLIHY_MAX_MAX_LEVEL], *preds[HERLIHY_MAX_MAX_LEVEL];
sl_node_t *node_todel, *prev_pred;
sl_node_t *pred, *succ;
int is_marked, toplevel, highest_locked, i, valid, found;
unsigned int backoff;
node_todel = NULL;
is_marked = 0;
toplevel = -1;
backoff = 1;
PARSE_START_TS(2);
while(1)
{
UPDATE_TRY();
found = optimistic_search(set, key, preds, succs, 1);
PARSE_END_TS(2, lat_parsing_rem);
/* If not marked and ok to delete, then mark it */
if (is_marked || (found != -1 && ok_to_delete(succs[found], found)))
{
GL_LOCK(set->lock); /* when GL_[UN]LOCK is defined the [UN]LOCK is not ;-) */
if (!is_marked)
{
node_todel = succs[found];
LOCK(ND_GET_LOCK(node_todel));
toplevel = node_todel->toplevel;
/* Unless it has been marked meanwhile */
if (node_todel->marked)
{
GL_UNLOCK(set->lock);
UNLOCK(ND_GET_LOCK(node_todel));
PARSE_END_INC(lat_parsing_rem);
return 0;
}
node_todel->marked = 1;
is_marked = 1;
}
/* Physical deletion */
highest_locked = -1;
prev_pred = NULL;
valid = 1;
for (i = 0; valid && (i < toplevel); i++)
{
pred = preds[i];
succ = succs[i];
if (pred != prev_pred)
{
LOCK(ND_GET_LOCK(pred));
highest_locked = i;
prev_pred = pred;
}
valid = (!pred->marked && ((volatile sl_node_t*) pred->next[i] ==
(volatile sl_node_t*) succ));
}
if (!valid)
{
unlock_levels(set, preds, highest_locked);
if (backoff > 5000)
{
nop_rep(backoff & MAX_BACKOFF);
}
backoff <<= 1;
continue;
}
for (i = (toplevel-1); i >= 0; i--)
{
preds[i]->next[i] = node_todel->next[i];
}
sval_t val = node_todel->val;
#if GC == 1
ssmem_free(alloc, (void*) node_todel);
#endif
UNLOCK(ND_GET_LOCK(node_todel));
unlock_levels(set, preds, highest_locked);
PARSE_END_INC(lat_parsing_rem);
return val;
}
else
{
PARSE_END_INC(lat_parsing_rem);
return 0;
}
}
}
/*
* Function optimistic_insert stands for the add method of the original paper.
* Unlocking and freeing the memory are done at the right places.
*/
int
optimistic_insert(sl_intset_t *set, skey_t key, sval_t val)
{
sl_node_t *succs[HERLIHY_MAX_MAX_LEVEL], *preds[HERLIHY_MAX_MAX_LEVEL];
sl_node_t *node_found, *prev_pred, *new_node;
sl_node_t *pred, *succ;
int toplevel, highest_locked, i, valid, found;
unsigned int backoff;
toplevel = get_rand_level();
backoff = 1;
PARSE_START_TS(1);
while (1)
{
UPDATE_TRY();
found = optimistic_search(set, key, preds, succs, 1);
PARSE_END_TS(1, lat_parsing_put);
if (found != -1)
{
node_found = succs[found];
if (!node_found->marked)
{
while (!node_found->fullylinked)
{
PAUSE;
}
PARSE_END_INC(lat_parsing_put);
return 0;
}
continue;
}
GL_LOCK(set->lock); /* when GL_[UN]LOCK is defined the [UN]LOCK is not ;-) */
highest_locked = -1;
prev_pred = NULL;
valid = 1;
for (i = 0; valid && (i < toplevel); i++)
{
pred = preds[i];
succ = succs[i];
if (pred != prev_pred)
{
LOCK(ND_GET_LOCK(pred));
highest_locked = i;
prev_pred = pred;
}
valid = (!pred->marked && !succ->marked &&
((volatile sl_node_t*) pred->next[i] ==
(volatile sl_node_t*) succ));
}
if (!valid)
{ /* Unlock the predecessors before leaving */
unlock_levels(set, preds, highest_locked); /* unlocks the global-lock in the GL case */
if (backoff > 5000)
{
nop_rep(backoff & MAX_BACKOFF);
}
backoff <<= 1;
continue;
}
new_node = sl_new_simple_node(key, val, toplevel, 0);
for (i = 0; i < toplevel; i++)
{
new_node->next[i] = succs[i];
}
#if defined(__tile__)
MEM_BARRIER;
#endif
for (i = 0; i < toplevel; i++)
{
preds[i]->next[i] = new_node;
}
new_node->fullylinked = 1;
unlock_levels(set, preds, highest_locked);
PARSE_END_INC(lat_parsing_put);
return 1;
}
}
