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kmp_tasking.cpp
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kmp_tasking.cpp
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/*
* kmp_tasking.cpp -- OpenMP 3.0 tasking support.
*/
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "kmp.h"
#include "kmp_i18n.h"
#include "kmp_itt.h"
#include "kmp_stats.h"
#include "kmp_wait_release.h"
#include "kmp_taskdeps.h"
#if OMPT_SUPPORT
#include "ompt-specific.h"
#endif
#include "tsan_annotations.h"
/* forward declaration */
static void __kmp_enable_tasking(kmp_task_team_t *task_team,
kmp_info_t *this_thr);
static void __kmp_alloc_task_deque(kmp_info_t *thread,
kmp_thread_data_t *thread_data);
static int __kmp_realloc_task_threads_data(kmp_info_t *thread,
kmp_task_team_t *task_team);
static void __kmp_bottom_half_finish_proxy(kmp_int32 gtid, kmp_task_t *ptask);
#ifdef BUILD_TIED_TASK_STACK
// __kmp_trace_task_stack: print the tied tasks from the task stack in order
// from top do bottom
//
// gtid: global thread identifier for thread containing stack
// thread_data: thread data for task team thread containing stack
// threshold: value above which the trace statement triggers
// location: string identifying call site of this function (for trace)
static void __kmp_trace_task_stack(kmp_int32 gtid,
kmp_thread_data_t *thread_data,
int threshold, char *location) {
kmp_task_stack_t *task_stack = &thread_data->td.td_susp_tied_tasks;
kmp_taskdata_t **stack_top = task_stack->ts_top;
kmp_int32 entries = task_stack->ts_entries;
kmp_taskdata_t *tied_task;
KA_TRACE(
threshold,
("__kmp_trace_task_stack(start): location = %s, gtid = %d, entries = %d, "
"first_block = %p, stack_top = %p \n",
location, gtid, entries, task_stack->ts_first_block, stack_top));
KMP_DEBUG_ASSERT(stack_top != NULL);
KMP_DEBUG_ASSERT(entries > 0);
while (entries != 0) {
KMP_DEBUG_ASSERT(stack_top != &task_stack->ts_first_block.sb_block[0]);
// fix up ts_top if we need to pop from previous block
if (entries & TASK_STACK_INDEX_MASK == 0) {
kmp_stack_block_t *stack_block = (kmp_stack_block_t *)(stack_top);
stack_block = stack_block->sb_prev;
stack_top = &stack_block->sb_block[TASK_STACK_BLOCK_SIZE];
}
// finish bookkeeping
stack_top--;
entries--;
tied_task = *stack_top;
KMP_DEBUG_ASSERT(tied_task != NULL);
KMP_DEBUG_ASSERT(tied_task->td_flags.tasktype == TASK_TIED);
KA_TRACE(threshold,
("__kmp_trace_task_stack(%s): gtid=%d, entry=%d, "
"stack_top=%p, tied_task=%p\n",
location, gtid, entries, stack_top, tied_task));
}
KMP_DEBUG_ASSERT(stack_top == &task_stack->ts_first_block.sb_block[0]);
KA_TRACE(threshold,
("__kmp_trace_task_stack(exit): location = %s, gtid = %d\n",
location, gtid));
}
// __kmp_init_task_stack: initialize the task stack for the first time
// after a thread_data structure is created.
// It should not be necessary to do this again (assuming the stack works).
//
// gtid: global thread identifier of calling thread
// thread_data: thread data for task team thread containing stack
static void __kmp_init_task_stack(kmp_int32 gtid,
kmp_thread_data_t *thread_data) {
kmp_task_stack_t *task_stack = &thread_data->td.td_susp_tied_tasks;
kmp_stack_block_t *first_block;
// set up the first block of the stack
first_block = &task_stack->ts_first_block;
task_stack->ts_top = (kmp_taskdata_t **)first_block;
memset((void *)first_block, '\0',
TASK_STACK_BLOCK_SIZE * sizeof(kmp_taskdata_t *));
// initialize the stack to be empty
task_stack->ts_entries = TASK_STACK_EMPTY;
first_block->sb_next = NULL;
first_block->sb_prev = NULL;
}
// __kmp_free_task_stack: free the task stack when thread_data is destroyed.
//
// gtid: global thread identifier for calling thread
// thread_data: thread info for thread containing stack
static void __kmp_free_task_stack(kmp_int32 gtid,
kmp_thread_data_t *thread_data) {
kmp_task_stack_t *task_stack = &thread_data->td.td_susp_tied_tasks;
kmp_stack_block_t *stack_block = &task_stack->ts_first_block;
KMP_DEBUG_ASSERT(task_stack->ts_entries == TASK_STACK_EMPTY);
// free from the second block of the stack
while (stack_block != NULL) {
kmp_stack_block_t *next_block = (stack_block) ? stack_block->sb_next : NULL;
stack_block->sb_next = NULL;
stack_block->sb_prev = NULL;
if (stack_block != &task_stack->ts_first_block) {
__kmp_thread_free(thread,
stack_block); // free the block, if not the first
}
stack_block = next_block;
}
// initialize the stack to be empty
task_stack->ts_entries = 0;
task_stack->ts_top = NULL;
}
// __kmp_push_task_stack: Push the tied task onto the task stack.
// Grow the stack if necessary by allocating another block.
//
// gtid: global thread identifier for calling thread
// thread: thread info for thread containing stack
// tied_task: the task to push on the stack
static void __kmp_push_task_stack(kmp_int32 gtid, kmp_info_t *thread,
kmp_taskdata_t *tied_task) {
// GEH - need to consider what to do if tt_threads_data not allocated yet
kmp_thread_data_t *thread_data =
&thread->th.th_task_team->tt.tt_threads_data[__kmp_tid_from_gtid(gtid)];
kmp_task_stack_t *task_stack = &thread_data->td.td_susp_tied_tasks;
if (tied_task->td_flags.team_serial || tied_task->td_flags.tasking_ser) {
return; // Don't push anything on stack if team or team tasks are serialized
}
KMP_DEBUG_ASSERT(tied_task->td_flags.tasktype == TASK_TIED);
KMP_DEBUG_ASSERT(task_stack->ts_top != NULL);
KA_TRACE(20,
("__kmp_push_task_stack(enter): GTID: %d; THREAD: %p; TASK: %p\n",
gtid, thread, tied_task));
// Store entry
*(task_stack->ts_top) = tied_task;
// Do bookkeeping for next push
task_stack->ts_top++;
task_stack->ts_entries++;
if (task_stack->ts_entries & TASK_STACK_INDEX_MASK == 0) {
// Find beginning of this task block
kmp_stack_block_t *stack_block =
(kmp_stack_block_t *)(task_stack->ts_top - TASK_STACK_BLOCK_SIZE);
// Check if we already have a block
if (stack_block->sb_next !=
NULL) { // reset ts_top to beginning of next block
task_stack->ts_top = &stack_block->sb_next->sb_block[0];
} else { // Alloc new block and link it up
kmp_stack_block_t *new_block = (kmp_stack_block_t *)__kmp_thread_calloc(
thread, sizeof(kmp_stack_block_t));
task_stack->ts_top = &new_block->sb_block[0];
stack_block->sb_next = new_block;
new_block->sb_prev = stack_block;
new_block->sb_next = NULL;
KA_TRACE(
30,
("__kmp_push_task_stack(): GTID: %d; TASK: %p; Alloc new block: %p\n",
gtid, tied_task, new_block));
}
}
KA_TRACE(20, ("__kmp_push_task_stack(exit): GTID: %d; TASK: %p\n", gtid,
tied_task));
}
// __kmp_pop_task_stack: Pop the tied task from the task stack. Don't return
// the task, just check to make sure it matches the ending task passed in.
//
// gtid: global thread identifier for the calling thread
// thread: thread info structure containing stack
// tied_task: the task popped off the stack
// ending_task: the task that is ending (should match popped task)
static void __kmp_pop_task_stack(kmp_int32 gtid, kmp_info_t *thread,
kmp_taskdata_t *ending_task) {
// GEH - need to consider what to do if tt_threads_data not allocated yet
kmp_thread_data_t *thread_data =
&thread->th.th_task_team->tt_threads_data[__kmp_tid_from_gtid(gtid)];
kmp_task_stack_t *task_stack = &thread_data->td.td_susp_tied_tasks;
kmp_taskdata_t *tied_task;
if (ending_task->td_flags.team_serial || ending_task->td_flags.tasking_ser) {
// Don't pop anything from stack if team or team tasks are serialized
return;
}
KMP_DEBUG_ASSERT(task_stack->ts_top != NULL);
KMP_DEBUG_ASSERT(task_stack->ts_entries > 0);
KA_TRACE(20, ("__kmp_pop_task_stack(enter): GTID: %d; THREAD: %p\n", gtid,
thread));
// fix up ts_top if we need to pop from previous block
if (task_stack->ts_entries & TASK_STACK_INDEX_MASK == 0) {
kmp_stack_block_t *stack_block = (kmp_stack_block_t *)(task_stack->ts_top);
stack_block = stack_block->sb_prev;
task_stack->ts_top = &stack_block->sb_block[TASK_STACK_BLOCK_SIZE];
}
// finish bookkeeping
task_stack->ts_top--;
task_stack->ts_entries--;
tied_task = *(task_stack->ts_top);
KMP_DEBUG_ASSERT(tied_task != NULL);
KMP_DEBUG_ASSERT(tied_task->td_flags.tasktype == TASK_TIED);
KMP_DEBUG_ASSERT(tied_task == ending_task); // If we built the stack correctly
KA_TRACE(20, ("__kmp_pop_task_stack(exit): GTID: %d; TASK: %p\n", gtid,
tied_task));
return;
}
#endif /* BUILD_TIED_TASK_STACK */
// returns 1 if new task is allowed to execute, 0 otherwise
// checks Task Scheduling constraint (if requested) and
// mutexinoutset dependencies if any
static bool __kmp_task_is_allowed(int gtid, const kmp_int32 is_constrained,
const kmp_taskdata_t *tasknew,
const kmp_taskdata_t *taskcurr) {
if (is_constrained && (tasknew->td_flags.tiedness == TASK_TIED)) {
// Check if the candidate obeys the Task Scheduling Constraints (TSC)
// only descendant of all deferred tied tasks can be scheduled, checking
// the last one is enough, as it in turn is the descendant of all others
kmp_taskdata_t *current = taskcurr->td_last_tied;
KMP_DEBUG_ASSERT(current != NULL);
// check if the task is not suspended on barrier
if (current->td_flags.tasktype == TASK_EXPLICIT ||
current->td_taskwait_thread > 0) { // <= 0 on barrier
kmp_int32 level = current->td_level;
kmp_taskdata_t *parent = tasknew->td_parent;
while (parent != current && parent->td_level > level) {
// check generation up to the level of the current task
parent = parent->td_parent;
KMP_DEBUG_ASSERT(parent != NULL);
}
if (parent != current)
return false;
}
}
// Check mutexinoutset dependencies, acquire locks
kmp_depnode_t *node = tasknew->td_depnode;
if (node && (node->dn.mtx_num_locks > 0)) {
for (int i = 0; i < node->dn.mtx_num_locks; ++i) {
KMP_DEBUG_ASSERT(node->dn.mtx_locks[i] != NULL);
if (__kmp_test_lock(node->dn.mtx_locks[i], gtid))
continue;
// could not get the lock, release previous locks
for (int j = i - 1; j >= 0; --j)
__kmp_release_lock(node->dn.mtx_locks[j], gtid);
return false;
}
// negative num_locks means all locks acquired successfully
node->dn.mtx_num_locks = -node->dn.mtx_num_locks;
}
return true;
}
// __kmp_realloc_task_deque:
// Re-allocates a task deque for a particular thread, copies the content from
// the old deque and adjusts the necessary data structures relating to the
// deque. This operation must be done with the deque_lock being held
static void __kmp_realloc_task_deque(kmp_info_t *thread,
kmp_thread_data_t *thread_data) {
kmp_int32 size = TASK_DEQUE_SIZE(thread_data->td);
kmp_int32 new_size = 2 * size;
KE_TRACE(10, ("__kmp_realloc_task_deque: T#%d reallocating deque[from %d to "
"%d] for thread_data %p\n",
__kmp_gtid_from_thread(thread), size, new_size, thread_data));
kmp_taskdata_t **new_deque =
(kmp_taskdata_t **)__kmp_allocate(new_size * sizeof(kmp_taskdata_t *));
int i, j;
for (i = thread_data->td.td_deque_head, j = 0; j < size;
i = (i + 1) & TASK_DEQUE_MASK(thread_data->td), j++)
new_deque[j] = thread_data->td.td_deque[i];
__kmp_free(thread_data->td.td_deque);
thread_data->td.td_deque_head = 0;
thread_data->td.td_deque_tail = size;
thread_data->td.td_deque = new_deque;
thread_data->td.td_deque_size = new_size;
}
// __kmp_push_task: Add a task to the thread's deque
static kmp_int32 __kmp_push_task(kmp_int32 gtid, kmp_task_t *task) {
kmp_info_t *thread = __kmp_threads[gtid];
kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
kmp_task_team_t *task_team = thread->th.th_task_team;
kmp_int32 tid = __kmp_tid_from_gtid(gtid);
kmp_thread_data_t *thread_data;
KA_TRACE(20,
("__kmp_push_task: T#%d trying to push task %p.\n", gtid, taskdata));
if (taskdata->td_flags.tiedness == TASK_UNTIED) {
// untied task needs to increment counter so that the task structure is not
// freed prematurely
kmp_int32 counter = 1 + KMP_ATOMIC_INC(&taskdata->td_untied_count);
KMP_DEBUG_USE_VAR(counter);
KA_TRACE(
20,
("__kmp_push_task: T#%d untied_count (%d) incremented for task %p\n",
gtid, counter, taskdata));
}
// The first check avoids building task_team thread data if serialized
if (taskdata->td_flags.task_serial) {
KA_TRACE(20, ("__kmp_push_task: T#%d team serialized; returning "
"TASK_NOT_PUSHED for task %p\n",
gtid, taskdata));
return TASK_NOT_PUSHED;
}
// Now that serialized tasks have returned, we can assume that we are not in
// immediate exec mode
KMP_DEBUG_ASSERT(__kmp_tasking_mode != tskm_immediate_exec);
if (!KMP_TASKING_ENABLED(task_team)) {
__kmp_enable_tasking(task_team, thread);
}
KMP_DEBUG_ASSERT(TCR_4(task_team->tt.tt_found_tasks) == TRUE);
KMP_DEBUG_ASSERT(TCR_PTR(task_team->tt.tt_threads_data) != NULL);
// Find tasking deque specific to encountering thread
thread_data = &task_team->tt.tt_threads_data[tid];
// No lock needed since only owner can allocate
if (thread_data->td.td_deque == NULL) {
__kmp_alloc_task_deque(thread, thread_data);
}
int locked = 0;
// Check if deque is full
if (TCR_4(thread_data->td.td_deque_ntasks) >=
TASK_DEQUE_SIZE(thread_data->td)) {
if (__kmp_enable_task_throttling &&
__kmp_task_is_allowed(gtid, __kmp_task_stealing_constraint, taskdata,
thread->th.th_current_task)) {
KA_TRACE(20, ("__kmp_push_task: T#%d deque is full; returning "
"TASK_NOT_PUSHED for task %p\n",
gtid, taskdata));
return TASK_NOT_PUSHED;
} else {
__kmp_acquire_bootstrap_lock(&thread_data->td.td_deque_lock);
locked = 1;
// expand deque to push the task which is not allowed to execute
__kmp_realloc_task_deque(thread, thread_data);
}
}
// Lock the deque for the task push operation
if (!locked) {
__kmp_acquire_bootstrap_lock(&thread_data->td.td_deque_lock);
// Need to recheck as we can get a proxy task from thread outside of OpenMP
if (TCR_4(thread_data->td.td_deque_ntasks) >=
TASK_DEQUE_SIZE(thread_data->td)) {
if (__kmp_enable_task_throttling &&
__kmp_task_is_allowed(gtid, __kmp_task_stealing_constraint, taskdata,
thread->th.th_current_task)) {
__kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
KA_TRACE(20, ("__kmp_push_task: T#%d deque is full on 2nd check; "
"returning TASK_NOT_PUSHED for task %p\n",
gtid, taskdata));
return TASK_NOT_PUSHED;
} else {
// expand deque to push the task which is not allowed to execute
__kmp_realloc_task_deque(thread, thread_data);
}
}
}
// Must have room since no thread can add tasks but calling thread
KMP_DEBUG_ASSERT(TCR_4(thread_data->td.td_deque_ntasks) <
TASK_DEQUE_SIZE(thread_data->td));
thread_data->td.td_deque[thread_data->td.td_deque_tail] =
taskdata; // Push taskdata
// Wrap index.
thread_data->td.td_deque_tail =
(thread_data->td.td_deque_tail + 1) & TASK_DEQUE_MASK(thread_data->td);
TCW_4(thread_data->td.td_deque_ntasks,
TCR_4(thread_data->td.td_deque_ntasks) + 1); // Adjust task count
KA_TRACE(20, ("__kmp_push_task: T#%d returning TASK_SUCCESSFULLY_PUSHED: "
"task=%p ntasks=%d head=%u tail=%u\n",
gtid, taskdata, thread_data->td.td_deque_ntasks,
thread_data->td.td_deque_head, thread_data->td.td_deque_tail));
__kmp_release_bootstrap_lock(&thread_data->td.td_deque_lock);
return TASK_SUCCESSFULLY_PUSHED;
}
// __kmp_pop_current_task_from_thread: set up current task from called thread
// when team ends
//
// this_thr: thread structure to set current_task in.
void __kmp_pop_current_task_from_thread(kmp_info_t *this_thr) {
KF_TRACE(10, ("__kmp_pop_current_task_from_thread(enter): T#%d "
"this_thread=%p, curtask=%p, "
"curtask_parent=%p\n",
0, this_thr, this_thr->th.th_current_task,
this_thr->th.th_current_task->td_parent));
this_thr->th.th_current_task = this_thr->th.th_current_task->td_parent;
KF_TRACE(10, ("__kmp_pop_current_task_from_thread(exit): T#%d "
"this_thread=%p, curtask=%p, "
"curtask_parent=%p\n",
0, this_thr, this_thr->th.th_current_task,
this_thr->th.th_current_task->td_parent));
}
// __kmp_push_current_task_to_thread: set up current task in called thread for a
// new team
//
// this_thr: thread structure to set up
// team: team for implicit task data
// tid: thread within team to set up
void __kmp_push_current_task_to_thread(kmp_info_t *this_thr, kmp_team_t *team,
int tid) {
// current task of the thread is a parent of the new just created implicit
// tasks of new team
KF_TRACE(10, ("__kmp_push_current_task_to_thread(enter): T#%d this_thread=%p "
"curtask=%p "
"parent_task=%p\n",
tid, this_thr, this_thr->th.th_current_task,
team->t.t_implicit_task_taskdata[tid].td_parent));
KMP_DEBUG_ASSERT(this_thr != NULL);
if (tid == 0) {
if (this_thr->th.th_current_task != &team->t.t_implicit_task_taskdata[0]) {
team->t.t_implicit_task_taskdata[0].td_parent =
this_thr->th.th_current_task;
this_thr->th.th_current_task = &team->t.t_implicit_task_taskdata[0];
}
} else {
team->t.t_implicit_task_taskdata[tid].td_parent =
team->t.t_implicit_task_taskdata[0].td_parent;
this_thr->th.th_current_task = &team->t.t_implicit_task_taskdata[tid];
}
KF_TRACE(10, ("__kmp_push_current_task_to_thread(exit): T#%d this_thread=%p "
"curtask=%p "
"parent_task=%p\n",
tid, this_thr, this_thr->th.th_current_task,
team->t.t_implicit_task_taskdata[tid].td_parent));
}
// __kmp_task_start: bookkeeping for a task starting execution
//
// GTID: global thread id of calling thread
// task: task starting execution
// current_task: task suspending
static void __kmp_task_start(kmp_int32 gtid, kmp_task_t *task,
kmp_taskdata_t *current_task) {
kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
kmp_info_t *thread = __kmp_threads[gtid];
KA_TRACE(10,
("__kmp_task_start(enter): T#%d starting task %p: current_task=%p\n",
gtid, taskdata, current_task));
KMP_DEBUG_ASSERT(taskdata->td_flags.tasktype == TASK_EXPLICIT);
// mark currently executing task as suspended
// TODO: GEH - make sure root team implicit task is initialized properly.
// KMP_DEBUG_ASSERT( current_task -> td_flags.executing == 1 );
current_task->td_flags.executing = 0;
// Add task to stack if tied
#ifdef BUILD_TIED_TASK_STACK
if (taskdata->td_flags.tiedness == TASK_TIED) {
__kmp_push_task_stack(gtid, thread, taskdata);
}
#endif /* BUILD_TIED_TASK_STACK */
// mark starting task as executing and as current task
thread->th.th_current_task = taskdata;
KMP_DEBUG_ASSERT(taskdata->td_flags.started == 0 ||
taskdata->td_flags.tiedness == TASK_UNTIED);
KMP_DEBUG_ASSERT(taskdata->td_flags.executing == 0 ||
taskdata->td_flags.tiedness == TASK_UNTIED);
taskdata->td_flags.started = 1;
taskdata->td_flags.executing = 1;
KMP_DEBUG_ASSERT(taskdata->td_flags.complete == 0);
KMP_DEBUG_ASSERT(taskdata->td_flags.freed == 0);
// GEH TODO: shouldn't we pass some sort of location identifier here?
// APT: yes, we will pass location here.
// need to store current thread state (in a thread or taskdata structure)
// before setting work_state, otherwise wrong state is set after end of task
KA_TRACE(10, ("__kmp_task_start(exit): T#%d task=%p\n", gtid, taskdata));
return;
}
#if OMPT_SUPPORT
//------------------------------------------------------------------------------
// __ompt_task_init:
// Initialize OMPT fields maintained by a task. This will only be called after
// ompt_start_tool, so we already know whether ompt is enabled or not.
static inline void __ompt_task_init(kmp_taskdata_t *task, int tid) {
// The calls to __ompt_task_init already have the ompt_enabled condition.
task->ompt_task_info.task_data.value = 0;
task->ompt_task_info.frame.exit_frame = ompt_data_none;
task->ompt_task_info.frame.enter_frame = ompt_data_none;
task->ompt_task_info.frame.exit_frame_flags = ompt_frame_runtime | ompt_frame_framepointer;
task->ompt_task_info.frame.enter_frame_flags = ompt_frame_runtime | ompt_frame_framepointer;
task->ompt_task_info.ndeps = 0;
task->ompt_task_info.deps = NULL;
}
// __ompt_task_start:
// Build and trigger task-begin event
static inline void __ompt_task_start(kmp_task_t *task,
kmp_taskdata_t *current_task,
kmp_int32 gtid) {
kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
ompt_task_status_t status = ompt_task_switch;
if (__kmp_threads[gtid]->th.ompt_thread_info.ompt_task_yielded) {
status = ompt_task_yield;
__kmp_threads[gtid]->th.ompt_thread_info.ompt_task_yielded = 0;
}
/* let OMPT know that we're about to run this task */
if (ompt_enabled.ompt_callback_task_schedule) {
ompt_callbacks.ompt_callback(ompt_callback_task_schedule)(
&(current_task->ompt_task_info.task_data), status,
&(taskdata->ompt_task_info.task_data));
}
taskdata->ompt_task_info.scheduling_parent = current_task;
}
// __ompt_task_finish:
// Build and trigger final task-schedule event
static inline void
__ompt_task_finish(kmp_task_t *task, kmp_taskdata_t *resumed_task,
ompt_task_status_t status = ompt_task_complete) {
kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
if (__kmp_omp_cancellation && taskdata->td_taskgroup &&
taskdata->td_taskgroup->cancel_request == cancel_taskgroup) {
status = ompt_task_cancel;
}
/* let OMPT know that we're returning to the callee task */
if (ompt_enabled.ompt_callback_task_schedule) {
ompt_callbacks.ompt_callback(ompt_callback_task_schedule)(
&(taskdata->ompt_task_info.task_data), status,
&((resumed_task ? resumed_task
: (taskdata->ompt_task_info.scheduling_parent
? taskdata->ompt_task_info.scheduling_parent
: taskdata->td_parent))
->ompt_task_info.task_data));
}
}
#endif
template <bool ompt>
static void __kmpc_omp_task_begin_if0_template(ident_t *loc_ref, kmp_int32 gtid,
kmp_task_t *task,
void *frame_address,
void *return_address) {
kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
kmp_taskdata_t *current_task = __kmp_threads[gtid]->th.th_current_task;
KA_TRACE(10, ("__kmpc_omp_task_begin_if0(enter): T#%d loc=%p task=%p "
"current_task=%p\n",
gtid, loc_ref, taskdata, current_task));
if (taskdata->td_flags.tiedness == TASK_UNTIED) {
// untied task needs to increment counter so that the task structure is not
// freed prematurely
kmp_int32 counter = 1 + KMP_ATOMIC_INC(&taskdata->td_untied_count);
KMP_DEBUG_USE_VAR(counter);
KA_TRACE(20, ("__kmpc_omp_task_begin_if0: T#%d untied_count (%d) "
"incremented for task %p\n",
gtid, counter, taskdata));
}
taskdata->td_flags.task_serial =
1; // Execute this task immediately, not deferred.
__kmp_task_start(gtid, task, current_task);
#if OMPT_SUPPORT
if (ompt) {
if (current_task->ompt_task_info.frame.enter_frame.ptr == NULL) {
current_task->ompt_task_info.frame.enter_frame.ptr =
taskdata->ompt_task_info.frame.exit_frame.ptr = frame_address;
current_task->ompt_task_info.frame.enter_frame_flags =
taskdata->ompt_task_info.frame.exit_frame_flags = ompt_frame_application | ompt_frame_framepointer;
}
if (ompt_enabled.ompt_callback_task_create) {
ompt_task_info_t *parent_info = &(current_task->ompt_task_info);
ompt_callbacks.ompt_callback(ompt_callback_task_create)(
&(parent_info->task_data), &(parent_info->frame),
&(taskdata->ompt_task_info.task_data),
ompt_task_explicit | TASK_TYPE_DETAILS_FORMAT(taskdata), 0,
return_address);
}
__ompt_task_start(task, current_task, gtid);
}
#endif // OMPT_SUPPORT
KA_TRACE(10, ("__kmpc_omp_task_begin_if0(exit): T#%d loc=%p task=%p,\n", gtid,
loc_ref, taskdata));
}
#if OMPT_SUPPORT
OMPT_NOINLINE
static void __kmpc_omp_task_begin_if0_ompt(ident_t *loc_ref, kmp_int32 gtid,
kmp_task_t *task,
void *frame_address,
void *return_address) {
__kmpc_omp_task_begin_if0_template<true>(loc_ref, gtid, task, frame_address,
return_address);
}
#endif // OMPT_SUPPORT
// __kmpc_omp_task_begin_if0: report that a given serialized task has started
// execution
//
// loc_ref: source location information; points to beginning of task block.
// gtid: global thread number.
// task: task thunk for the started task.
void __kmpc_omp_task_begin_if0(ident_t *loc_ref, kmp_int32 gtid,
kmp_task_t *task) {
#if OMPT_SUPPORT
if (UNLIKELY(ompt_enabled.enabled)) {
OMPT_STORE_RETURN_ADDRESS(gtid);
__kmpc_omp_task_begin_if0_ompt(loc_ref, gtid, task,
OMPT_GET_FRAME_ADDRESS(1),
OMPT_LOAD_RETURN_ADDRESS(gtid));
return;
}
#endif
__kmpc_omp_task_begin_if0_template<false>(loc_ref, gtid, task, NULL, NULL);
}
#ifdef TASK_UNUSED
// __kmpc_omp_task_begin: report that a given task has started execution
// NEVER GENERATED BY COMPILER, DEPRECATED!!!
void __kmpc_omp_task_begin(ident_t *loc_ref, kmp_int32 gtid, kmp_task_t *task) {
kmp_taskdata_t *current_task = __kmp_threads[gtid]->th.th_current_task;
KA_TRACE(
10,
("__kmpc_omp_task_begin(enter): T#%d loc=%p task=%p current_task=%p\n",
gtid, loc_ref, KMP_TASK_TO_TASKDATA(task), current_task));
__kmp_task_start(gtid, task, current_task);
KA_TRACE(10, ("__kmpc_omp_task_begin(exit): T#%d loc=%p task=%p,\n", gtid,
loc_ref, KMP_TASK_TO_TASKDATA(task)));
return;
}
#endif // TASK_UNUSED
// __kmp_free_task: free the current task space and the space for shareds
//
// gtid: Global thread ID of calling thread
// taskdata: task to free
// thread: thread data structure of caller
static void __kmp_free_task(kmp_int32 gtid, kmp_taskdata_t *taskdata,
kmp_info_t *thread) {
KA_TRACE(30, ("__kmp_free_task: T#%d freeing data from task %p\n", gtid,
taskdata));
// Check to make sure all flags and counters have the correct values
KMP_DEBUG_ASSERT(taskdata->td_flags.tasktype == TASK_EXPLICIT);
KMP_DEBUG_ASSERT(taskdata->td_flags.executing == 0);
KMP_DEBUG_ASSERT(taskdata->td_flags.complete == 1);
KMP_DEBUG_ASSERT(taskdata->td_flags.freed == 0);
KMP_DEBUG_ASSERT(taskdata->td_allocated_child_tasks == 0 ||
taskdata->td_flags.task_serial == 1);
KMP_DEBUG_ASSERT(taskdata->td_incomplete_child_tasks == 0);
taskdata->td_flags.freed = 1;
ANNOTATE_HAPPENS_BEFORE(taskdata);
// deallocate the taskdata and shared variable blocks associated with this task
#if USE_FAST_MEMORY
__kmp_fast_free(thread, taskdata);
#else /* ! USE_FAST_MEMORY */
__kmp_thread_free(thread, taskdata);
#endif
KA_TRACE(20, ("__kmp_free_task: T#%d freed task %p\n", gtid, taskdata));
}
// __kmp_free_task_and_ancestors: free the current task and ancestors without
// children
//
// gtid: Global thread ID of calling thread
// taskdata: task to free
// thread: thread data structure of caller
static void __kmp_free_task_and_ancestors(kmp_int32 gtid,
kmp_taskdata_t *taskdata,
kmp_info_t *thread) {
// Proxy tasks must always be allowed to free their parents
// because they can be run in background even in serial mode.
kmp_int32 team_serial =
(taskdata->td_flags.team_serial || taskdata->td_flags.tasking_ser) &&
!taskdata->td_flags.proxy;
KMP_DEBUG_ASSERT(taskdata->td_flags.tasktype == TASK_EXPLICIT);
kmp_int32 children = KMP_ATOMIC_DEC(&taskdata->td_allocated_child_tasks) - 1;
KMP_DEBUG_ASSERT(children >= 0);
// Now, go up the ancestor tree to see if any ancestors can now be freed.
while (children == 0) {
kmp_taskdata_t *parent_taskdata = taskdata->td_parent;
KA_TRACE(20, ("__kmp_free_task_and_ancestors(enter): T#%d task %p complete "
"and freeing itself\n",
gtid, taskdata));
// --- Deallocate my ancestor task ---
__kmp_free_task(gtid, taskdata, thread);
taskdata = parent_taskdata;
if (team_serial)
return;
// Stop checking ancestors at implicit task instead of walking up ancestor
// tree to avoid premature deallocation of ancestors.
if (taskdata->td_flags.tasktype == TASK_IMPLICIT) {
if (taskdata->td_dephash) { // do we need to cleanup dephash?
int children = KMP_ATOMIC_LD_ACQ(&taskdata->td_incomplete_child_tasks);
kmp_tasking_flags_t flags_old = taskdata->td_flags;
if (children == 0 && flags_old.complete == 1) {
kmp_tasking_flags_t flags_new = flags_old;
flags_new.complete = 0;
if (KMP_COMPARE_AND_STORE_ACQ32(
RCAST(kmp_int32 *, &taskdata->td_flags),
*RCAST(kmp_int32 *, &flags_old),
*RCAST(kmp_int32 *, &flags_new))) {
KA_TRACE(100, ("__kmp_free_task_and_ancestors: T#%d cleans "
"dephash of implicit task %p\n",
gtid, taskdata));
// cleanup dephash of finished implicit task
__kmp_dephash_free_entries(thread, taskdata->td_dephash);
}
}
}
return;
}
// Predecrement simulated by "- 1" calculation
children = KMP_ATOMIC_DEC(&taskdata->td_allocated_child_tasks) - 1;
KMP_DEBUG_ASSERT(children >= 0);
}
KA_TRACE(
20, ("__kmp_free_task_and_ancestors(exit): T#%d task %p has %d children; "
"not freeing it yet\n",
gtid, taskdata, children));
}
// __kmp_task_finish: bookkeeping to do when a task finishes execution
//
// gtid: global thread ID for calling thread
// task: task to be finished
// resumed_task: task to be resumed. (may be NULL if task is serialized)
template <bool ompt>
static void __kmp_task_finish(kmp_int32 gtid, kmp_task_t *task,
kmp_taskdata_t *resumed_task) {
kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
kmp_info_t *thread = __kmp_threads[gtid];
kmp_task_team_t *task_team =
thread->th.th_task_team; // might be NULL for serial teams...
kmp_int32 children = 0;
KA_TRACE(10, ("__kmp_task_finish(enter): T#%d finishing task %p and resuming "
"task %p\n",
gtid, taskdata, resumed_task));
KMP_DEBUG_ASSERT(taskdata->td_flags.tasktype == TASK_EXPLICIT);
// Pop task from stack if tied
#ifdef BUILD_TIED_TASK_STACK
if (taskdata->td_flags.tiedness == TASK_TIED) {
__kmp_pop_task_stack(gtid, thread, taskdata);
}
#endif /* BUILD_TIED_TASK_STACK */
if (taskdata->td_flags.tiedness == TASK_UNTIED) {
// untied task needs to check the counter so that the task structure is not
// freed prematurely
kmp_int32 counter = KMP_ATOMIC_DEC(&taskdata->td_untied_count) - 1;
KA_TRACE(
20,
("__kmp_task_finish: T#%d untied_count (%d) decremented for task %p\n",
gtid, counter, taskdata));
if (counter > 0) {
// untied task is not done, to be continued possibly by other thread, do
// not free it now
if (resumed_task == NULL) {
KMP_DEBUG_ASSERT(taskdata->td_flags.task_serial);
resumed_task = taskdata->td_parent; // In a serialized task, the resumed
// task is the parent
}
thread->th.th_current_task = resumed_task; // restore current_task
resumed_task->td_flags.executing = 1; // resume previous task
KA_TRACE(10, ("__kmp_task_finish(exit): T#%d partially done task %p, "
"resuming task %p\n",
gtid, taskdata, resumed_task));
return;
}
}
#if OMPT_SUPPORT
if (ompt)
__ompt_task_finish(task, resumed_task);
#endif
// Check mutexinoutset dependencies, release locks
kmp_depnode_t *node = taskdata->td_depnode;
if (node && (node->dn.mtx_num_locks < 0)) {
// negative num_locks means all locks were acquired
node->dn.mtx_num_locks = -node->dn.mtx_num_locks;
for (int i = node->dn.mtx_num_locks - 1; i >= 0; --i) {
KMP_DEBUG_ASSERT(node->dn.mtx_locks[i] != NULL);
__kmp_release_lock(node->dn.mtx_locks[i], gtid);
}
}
KMP_DEBUG_ASSERT(taskdata->td_flags.complete == 0);
bool detach = false;
if (taskdata->td_flags.detachable == TASK_DETACHABLE) {
if (taskdata->td_allow_completion_event.type ==
KMP_EVENT_ALLOW_COMPLETION) {
// event hasn't been fulfilled yet. Try to detach task.
__kmp_acquire_tas_lock(&taskdata->td_allow_completion_event.lock, gtid);
if (taskdata->td_allow_completion_event.type ==
KMP_EVENT_ALLOW_COMPLETION) {
taskdata->td_flags.proxy = TASK_PROXY; // proxify!
detach = true;
}
__kmp_release_tas_lock(&taskdata->td_allow_completion_event.lock, gtid);
}
}
KMP_DEBUG_ASSERT(taskdata->td_flags.started == 1);
KMP_DEBUG_ASSERT(taskdata->td_flags.freed == 0);
if (!detach) {
taskdata->td_flags.complete = 1; // mark the task as completed
// Only need to keep track of count if team parallel and tasking not
// serialized
if (!(taskdata->td_flags.team_serial || taskdata->td_flags.tasking_ser)) {
// Predecrement simulated by "- 1" calculation
children =
KMP_ATOMIC_DEC(&taskdata->td_parent->td_incomplete_child_tasks) - 1;
KMP_DEBUG_ASSERT(children >= 0);
if (taskdata->td_taskgroup)
KMP_ATOMIC_DEC(&taskdata->td_taskgroup->count);
__kmp_release_deps(gtid, taskdata);
} else if (task_team && task_team->tt.tt_found_proxy_tasks) {
// if we found proxy tasks there could exist a dependency chain
// with the proxy task as origin
__kmp_release_deps(gtid, taskdata);
}
}
// td_flags.executing must be marked as 0 after __kmp_release_deps has been
// called. Othertwise, if a task is executed immediately from the release_deps
// code, the flag will be reset to 1 again by this same function
KMP_DEBUG_ASSERT(taskdata->td_flags.executing == 1);
taskdata->td_flags.executing = 0; // suspend the finishing task
KA_TRACE(
20, ("__kmp_task_finish: T#%d finished task %p, %d incomplete children\n",
gtid, taskdata, children));
/* If the tasks' destructor thunk flag has been set, we need to invoke the
destructor thunk that has been generated by the compiler. The code is
placed here, since at this point other tasks might have been released
hence overlapping the destructor invokations with some other work in the
released tasks. The OpenMP spec is not specific on when the destructors
are invoked, so we should be free to choose. */
if (taskdata->td_flags.destructors_thunk) {
kmp_routine_entry_t destr_thunk = task->data1.destructors;
KMP_ASSERT(destr_thunk);
destr_thunk(gtid, task);
}
// bookkeeping for resuming task:
// GEH - note tasking_ser => task_serial
KMP_DEBUG_ASSERT(
(taskdata->td_flags.tasking_ser || taskdata->td_flags.task_serial) ==
taskdata->td_flags.task_serial);
if (taskdata->td_flags.task_serial) {
if (resumed_task == NULL) {
resumed_task = taskdata->td_parent; // In a serialized task, the resumed
// task is the parent
}
} else {
KMP_DEBUG_ASSERT(resumed_task !=
NULL); // verify that resumed task is passed as argument
}
// Free this task and then ancestor tasks if they have no children.
// Restore th_current_task first as suggested by John:
// johnmc: if an asynchronous inquiry peers into the runtime system
// it doesn't see the freed task as the current task.
thread->th.th_current_task = resumed_task;
if (!detach)
__kmp_free_task_and_ancestors(gtid, taskdata, thread);
// TODO: GEH - make sure root team implicit task is initialized properly.
// KMP_DEBUG_ASSERT( resumed_task->td_flags.executing == 0 );
resumed_task->td_flags.executing = 1; // resume previous task
KA_TRACE(
10, ("__kmp_task_finish(exit): T#%d finished task %p, resuming task %p\n",
gtid, taskdata, resumed_task));
return;
}
template <bool ompt>
static void __kmpc_omp_task_complete_if0_template(ident_t *loc_ref,
kmp_int32 gtid,
kmp_task_t *task) {
KA_TRACE(10, ("__kmpc_omp_task_complete_if0(enter): T#%d loc=%p task=%p\n",
gtid, loc_ref, KMP_TASK_TO_TASKDATA(task)));
// this routine will provide task to resume
__kmp_task_finish<ompt>(gtid, task, NULL);
KA_TRACE(10, ("__kmpc_omp_task_complete_if0(exit): T#%d loc=%p task=%p\n",
gtid, loc_ref, KMP_TASK_TO_TASKDATA(task)));
#if OMPT_SUPPORT
if (ompt) {
ompt_frame_t *ompt_frame;
__ompt_get_task_info_internal(0, NULL, NULL, &ompt_frame, NULL, NULL);
ompt_frame->enter_frame = ompt_data_none;
ompt_frame->enter_frame_flags = ompt_frame_runtime | ompt_frame_framepointer;
}
#endif
return;
}
#if OMPT_SUPPORT
OMPT_NOINLINE
void __kmpc_omp_task_complete_if0_ompt(ident_t *loc_ref, kmp_int32 gtid,
kmp_task_t *task) {
__kmpc_omp_task_complete_if0_template<true>(loc_ref, gtid, task);
}
#endif // OMPT_SUPPORT
// __kmpc_omp_task_complete_if0: report that a task has completed execution
//
// loc_ref: source location information; points to end of task block.
// gtid: global thread number.
// task: task thunk for the completed task.
void __kmpc_omp_task_complete_if0(ident_t *loc_ref, kmp_int32 gtid,
kmp_task_t *task) {
#if OMPT_SUPPORT
if (UNLIKELY(ompt_enabled.enabled)) {
__kmpc_omp_task_complete_if0_ompt(loc_ref, gtid, task);
return;