void chpl_task_stdModulesInitialized(void) {
//
// The task table is implemented in Chapel code in the modules, so
// we can't use it, and thus can't support task reporting on ^C or
// deadlock, until the other modules on which it depends have been
// initialized and the supporting code here is set up. In this
// function we're guaranteed that is true, because it is called only
// after all the standard module initialization is complete.
//
//
// Register this main task in the task table.
//
if (taskreport) {
thread_private_data_t* tp = chpl_thread_getPrivateData();
chpldev_taskTable_add(tp->ptask->bundle.id,
tp->ptask->bundle.lineno, tp->ptask->bundle.filename,
(uint64_t) (intptr_t) tp->ptask);
chpldev_taskTable_set_active(tp->ptask->bundle.id);
chpl_thread_mutexInit(&taskTable_lock);
}
//
// Now we can do task reporting if the user requested it.
//
do_taskReport = taskreport;
}
void chpl_task_executeTasksInList(void** p_task_list_void) {
task_pool_p* p_task_list_head = (task_pool_p*) p_task_list_void;
task_pool_p curr_ptask;
task_pool_p child_ptask;
//
// If we're serial, all the tasks have already been executed.
//
if (chpl_task_getSerial())
return;
curr_ptask = get_current_ptask();
while (*p_task_list_head != NULL) {
chpl_fn_p task_to_run_fun = NULL;
// begin critical section
chpl_thread_mutexLock(&threading_lock);
if ((child_ptask = *p_task_list_head) != NULL) {
task_to_run_fun = child_ptask->fun;
dequeue_task(child_ptask);
}
// end critical section
chpl_thread_mutexUnlock(&threading_lock);
if (task_to_run_fun == NULL)
continue;
set_current_ptask(child_ptask);
// begin critical section
chpl_thread_mutexLock(&extra_task_lock);
extra_task_cnt++;
// end critical section
chpl_thread_mutexUnlock(&extra_task_lock);
if (do_taskReport) {
chpl_thread_mutexLock(&taskTable_lock);
chpldev_taskTable_set_suspended(curr_ptask->id);
chpldev_taskTable_set_active(child_ptask->id);
chpl_thread_mutexUnlock(&taskTable_lock);
}
if (blockreport)
initializeLockReportForThread();
chpl_task_do_callbacks(chpl_task_cb_event_kind_begin,
child_ptask->filename,
child_ptask->lineno,
child_ptask->id,
child_ptask->is_executeOn);
(*task_to_run_fun)(child_ptask->arg);
chpl_task_do_callbacks(chpl_task_cb_event_kind_end,
child_ptask->filename,
child_ptask->lineno,
child_ptask->id,
child_ptask->is_executeOn);
if (do_taskReport) {
chpl_thread_mutexLock(&taskTable_lock);
chpldev_taskTable_set_active(curr_ptask->id);
chpldev_taskTable_remove(child_ptask->id);
chpl_thread_mutexUnlock(&taskTable_lock);
}
// begin critical section
chpl_thread_mutexLock(&extra_task_lock);
extra_task_cnt--;
// end critical section
chpl_thread_mutexUnlock(&extra_task_lock);
set_current_ptask(curr_ptask);
chpl_mem_free(child_ptask, 0, 0);
}
}
//
// When we create a thread it runs this wrapper function, which just
// executes tasks out of the pool as they become available.
//
static void
thread_begin(void* ptask_void) {
task_pool_p ptask;
thread_private_data_t *tp;
tp = (thread_private_data_t*) chpl_mem_alloc(sizeof(thread_private_data_t),
CHPL_RT_MD_THREAD_PRV_DATA,
0, 0);
chpl_thread_setPrivateData(tp);
tp->lockRprt = NULL;
if (blockreport)
initializeLockReportForThread();
while (true) {
//
// wait for a task to be present in the task pool
//
// In revision 22137, we investigated whether it was beneficial to
// implement this while loop in a hybrid style, where depending on
// the number of tasks available, idle threads would either yield or
// wait on a condition variable to waken them. Through analysis, we
// realized this could potential create a case where a thread would
// become stranded, waiting for a condition signal that would never
// come. A potential solution to this was to keep a count of threads
// that were waiting on the signal, but since there was a performance
// impact from keeping it as a hybrid as opposed to merely yielding,
// it was decided that we would return to the simple yield case.
while (!task_pool_head) {
if (set_block_loc(0, CHPL_FILE_IDX_IDLE_TASK)) {
// all other tasks appear to be blocked
struct timeval deadline, now;
gettimeofday(&deadline, NULL);
deadline.tv_sec += 1;
do {
chpl_thread_yield();
if (!task_pool_head)
gettimeofday(&now, NULL);
} while (!task_pool_head
&& (now.tv_sec < deadline.tv_sec
|| (now.tv_sec == deadline.tv_sec
&& now.tv_usec < deadline.tv_usec)));
if (!task_pool_head) {
check_for_deadlock();
}
}
else {
do {
chpl_thread_yield();
} while (!task_pool_head);
}
unset_block_loc();
}
//
// Just now the pool had at least one task in it. Lock and see if
// there's something still there.
//
chpl_thread_mutexLock(&threading_lock);
if (!task_pool_head) {
chpl_thread_mutexUnlock(&threading_lock);
continue;
}
//
// We've found a task to run.
//
if (blockreport)
progress_cnt++;
//
// start new task; increment running count and remove task from pool
// also add to task to task-table (structure in ChapelRuntime that keeps
// track of currently running tasks for task-reports on deadlock or
// Ctrl+C).
//
ptask = task_pool_head;
idle_thread_cnt--;
running_task_cnt++;
dequeue_task(ptask);
// end critical section
chpl_thread_mutexUnlock(&threading_lock);
tp->ptask = ptask;
if (do_taskReport) {
chpl_thread_mutexLock(&taskTable_lock);
chpldev_taskTable_set_active(ptask->id);
chpl_thread_mutexUnlock(&taskTable_lock);
}
chpl_task_do_callbacks(chpl_task_cb_event_kind_begin,
ptask->filename,
ptask->lineno,
ptask->id,
ptask->is_executeOn);
(*ptask->fun)(ptask->arg);
chpl_task_do_callbacks(chpl_task_cb_event_kind_end,
ptask->filename,
ptask->lineno,
ptask->id,
ptask->is_executeOn);
if (do_taskReport) {
chpl_thread_mutexLock(&taskTable_lock);
chpldev_taskTable_remove(ptask->id);
chpl_thread_mutexUnlock(&taskTable_lock);
}
tp->ptask = NULL;
chpl_mem_free(ptask, 0, 0);
// begin critical section
chpl_thread_mutexLock(&threading_lock);
//
// finished task; decrement running count and increment idle count
//
assert(running_task_cnt > 0);
running_task_cnt--;
idle_thread_cnt++;
// end critical section
chpl_thread_mutexUnlock(&threading_lock);
}
}
void chpl_task_executeTasksInList(void** p_task_list_void) {
task_pool_p* p_task_list_head = (task_pool_p*) p_task_list_void;
task_pool_p curr_ptask;
task_pool_p child_ptask;
// Note: this function needs to tolerate an empty task
// list. That will happen for coforalls inside a serial block, say.
curr_ptask = get_current_ptask();
while (*p_task_list_head != NULL) {
chpl_fn_p task_to_run_fun = NULL;
// begin critical section
chpl_thread_mutexLock(&threading_lock);
if ((child_ptask = *p_task_list_head) != NULL) {
task_to_run_fun = child_ptask->bundle.requested_fn;
dequeue_task(child_ptask);
}
// end critical section
chpl_thread_mutexUnlock(&threading_lock);
if (task_to_run_fun == NULL)
continue;
set_current_ptask(child_ptask);
// begin critical section
chpl_thread_mutexLock(&extra_task_lock);
extra_task_cnt++;
// end critical section
chpl_thread_mutexUnlock(&extra_task_lock);
if (do_taskReport) {
chpl_thread_mutexLock(&taskTable_lock);
chpldev_taskTable_set_suspended(curr_ptask->bundle.id);
chpldev_taskTable_set_active(child_ptask->bundle.id);
chpl_thread_mutexUnlock(&taskTable_lock);
}
if (blockreport)
initializeLockReportForThread();
chpl_task_do_callbacks(chpl_task_cb_event_kind_begin,
child_ptask->bundle.requested_fid,
child_ptask->bundle.filename,
child_ptask->bundle.lineno,
child_ptask->bundle.id,
child_ptask->bundle.is_executeOn);
(*task_to_run_fun)(&child_ptask->bundle);
chpl_task_do_callbacks(chpl_task_cb_event_kind_end,
child_ptask->bundle.requested_fid,
child_ptask->bundle.filename,
child_ptask->bundle.lineno,
child_ptask->bundle.id,
child_ptask->bundle.is_executeOn);
if (do_taskReport) {
chpl_thread_mutexLock(&taskTable_lock);
chpldev_taskTable_set_active(curr_ptask->bundle.id);
chpldev_taskTable_remove(child_ptask->bundle.id);
chpl_thread_mutexUnlock(&taskTable_lock);
}
// begin critical section
chpl_thread_mutexLock(&extra_task_lock);
extra_task_cnt--;
// end critical section
chpl_thread_mutexUnlock(&extra_task_lock);
set_current_ptask(curr_ptask);
chpl_mem_free(child_ptask, 0, 0);
}
}
