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llvm/llvm-project/refs/heads/users/pierre-vh/split-eventtracker-basic/./openmp/runtime/src/kmp_taskdeps.cpp
blob: b1a0848fc722f65fb3237c05c74fd72a57d85d9c [file] [edit]
/*
* kmp_taskdeps.cpp
*/
//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//#define KMP_SUPPORT_GRAPH_OUTPUT 1
#include "kmp.h"
#include "kmp_io.h"
#include "kmp_wait_release.h"
#include "kmp_taskdeps.h"
#if OMPT_SUPPORT
#include "ompt-specific.h"
#endif
// TODO: Improve memory allocation? keep a list of pre-allocated structures?
// allocate in blocks? re-use list finished list entries?
// TODO: don't use atomic ref counters for stack-allocated nodes.
// TODO: find an alternate to atomic refs for heap-allocated nodes?
// TODO: Finish graph output support
// TODO: kmp_lock_t seems a tad to big (and heavy weight) for this. Check other
// runtime locks
// TODO: Any ITT support needed?
#ifdef KMP_SUPPORT_GRAPH_OUTPUT
static std::atomic<kmp_int32> kmp_node_id_seed = 0;
#endif
static void __kmp_init_node(kmp_depnode_t *node, bool on_stack) {
node->dn.successors = NULL;
node->dn.task = NULL; // will point to the right task
// once dependences have been processed
for (int i = 0; i < MAX_MTX_DEPS; ++i)
node->dn.mtx_locks[i] = NULL;
node->dn.mtx_num_locks = 0;
__kmp_init_lock(&node->dn.lock);
// Init creates the first reference. Bit 0 indicates that this node
// resides on the stack. The refcount is incremented and decremented in
// steps of two, maintaining use of even numbers for heap nodes and odd
// numbers for stack nodes.
KMP_ATOMIC_ST_RLX(&node->dn.nrefs, on_stack ? 3 : 2);
#ifdef KMP_SUPPORT_GRAPH_OUTPUT
node->dn.id = KMP_ATOMIC_INC(&kmp_node_id_seed);
#endif
#if USE_ITT_BUILD && USE_ITT_NOTIFY
__itt_sync_create(node, "OMP task dep node", NULL, 0);
#endif
}
static inline kmp_depnode_t *__kmp_node_ref(kmp_depnode_t *node) {
KMP_ATOMIC_ADD(&node->dn.nrefs, 2);
return node;
}
enum { KMP_DEPHASH_OTHER_SIZE = 97, KMP_DEPHASH_MASTER_SIZE = 997 };
size_t sizes[] = {997, 2003, 4001, 8191, 16001, 32003, 64007, 131071, 270029};
const size_t MAX_GEN = 8;
static inline size_t __kmp_dephash_hash(kmp_intptr_t addr, size_t hsize) {
// TODO alternate to try: set = (((Addr64)(addrUsefulBits * 9.618)) %
// m_num_sets );
return ((addr >> 6) ^ (addr >> 2)) % hsize;
}
static kmp_dephash_t *__kmp_dephash_extend(kmp_info_t *thread,
kmp_dephash_t *current_dephash) {
kmp_dephash_t *h;
size_t gen = current_dephash->generation + 1;
if (gen >= MAX_GEN)
return current_dephash;
size_t new_size = sizes[gen];
size_t size_to_allocate =
new_size * sizeof(kmp_dephash_entry_t *) + sizeof(kmp_dephash_t);
#if USE_FAST_MEMORY
h = (kmp_dephash_t *)__kmp_fast_allocate(thread, size_to_allocate);
#else
h = (kmp_dephash_t *)__kmp_thread_malloc(thread, size_to_allocate);
#endif
h->size = new_size;
h->nelements = current_dephash->nelements;
h->buckets = (kmp_dephash_entry **)(h + 1);
h->generation = gen;
h->nconflicts = 0;
h->last_all = current_dephash->last_all;
// make sure buckets are properly initialized
for (size_t i = 0; i < new_size; i++) {
h->buckets[i] = NULL;
}
// insert existing elements in the new table
for (size_t i = 0; i < current_dephash->size; i++) {
kmp_dephash_entry_t *next, *entry;
for (entry = current_dephash->buckets[i]; entry; entry = next) {
next = entry->next_in_bucket;
// Compute the new hash using the new size, and insert the entry in
// the new bucket.
size_t new_bucket = __kmp_dephash_hash(entry->addr, h->size);
entry->next_in_bucket = h->buckets[new_bucket];
if (entry->next_in_bucket) {
h->nconflicts++;
}
h->buckets[new_bucket] = entry;
}
}
// Free old hash table
#if USE_FAST_MEMORY
__kmp_fast_free(thread, current_dephash);
#else
__kmp_thread_free(thread, current_dephash);
#endif
return h;
}
static kmp_dephash_t *__kmp_dephash_create(kmp_info_t *thread,
kmp_taskdata_t *current_task) {
kmp_dephash_t *h;
size_t h_size;
if (current_task->td_flags.tasktype == TASK_IMPLICIT)
h_size = KMP_DEPHASH_MASTER_SIZE;
else
h_size = KMP_DEPHASH_OTHER_SIZE;
size_t size = h_size * sizeof(kmp_dephash_entry_t *) + sizeof(kmp_dephash_t);
#if USE_FAST_MEMORY
h = (kmp_dephash_t *)__kmp_fast_allocate(thread, size);
#else
h = (kmp_dephash_t *)__kmp_thread_malloc(thread, size);
#endif
h->size = h_size;
h->generation = 0;
h->nelements = 0;
h->nconflicts = 0;
h->buckets = (kmp_dephash_entry **)(h + 1);
h->last_all = NULL;
for (size_t i = 0; i < h_size; i++)
h->buckets[i] = 0;
return h;
}
static kmp_dephash_entry *__kmp_dephash_find(kmp_info_t *thread,
kmp_dephash_t **hash,
kmp_intptr_t addr) {
kmp_dephash_t *h = *hash;
if (h->nelements != 0 && h->nconflicts / h->size >= 1) {
*hash = __kmp_dephash_extend(thread, h);
h = *hash;
}
size_t bucket = __kmp_dephash_hash(addr, h->size);
kmp_dephash_entry_t *entry;
for (entry = h->buckets[bucket]; entry; entry = entry->next_in_bucket)
if (entry->addr == addr)
break;
if (entry == NULL) {
// create entry. This is only done by one thread so no locking required
#if USE_FAST_MEMORY
entry = (kmp_dephash_entry_t *)__kmp_fast_allocate(
thread, sizeof(kmp_dephash_entry_t));
#else
entry = (kmp_dephash_entry_t *)__kmp_thread_malloc(
thread, sizeof(kmp_dephash_entry_t));
#endif
entry->addr = addr;
if (!h->last_all) // no predecessor task with omp_all_memory dependence
entry->last_out = NULL;
else // else link the omp_all_memory depnode to the new entry
entry->last_out = __kmp_node_ref(h->last_all);
entry->last_set = NULL;
entry->prev_set = NULL;
entry->last_flag = 0;
entry->mtx_lock = NULL;
entry->next_in_bucket = h->buckets[bucket];
h->buckets[bucket] = entry;
h->nelements++;
if (entry->next_in_bucket)
h->nconflicts++;
}
return entry;
}
static kmp_depnode_list_t *__kmp_add_node(kmp_info_t *thread,
kmp_depnode_list_t *list,
kmp_depnode_t *node) {
kmp_depnode_list_t *new_head;
#if USE_FAST_MEMORY
new_head = (kmp_depnode_list_t *)__kmp_fast_allocate(
thread, sizeof(kmp_depnode_list_t));
#else
new_head = (kmp_depnode_list_t *)__kmp_thread_malloc(
thread, sizeof(kmp_depnode_list_t));
#endif
new_head->node = __kmp_node_ref(node);
new_head->next = list;
return new_head;
}
static inline void __kmp_track_dependence(kmp_int32 gtid, kmp_depnode_t *source,
kmp_depnode_t *sink,
kmp_task_t *sink_task) {
#if OMP_TASKGRAPH_EXPERIMENTAL
kmp_taskdata_t *task_source = KMP_TASK_TO_TASKDATA(source->dn.task);
kmp_taskdata_t *task_sink = KMP_TASK_TO_TASKDATA(sink_task);
if (source->dn.task && sink_task) {
// Not supporting dependency between two tasks that one is within the TDG
// and the other is not
KMP_ASSERT(task_source->is_taskgraph == task_sink->is_taskgraph);
}
if (task_sink->is_taskgraph &&
__kmp_tdg_is_recording(task_sink->tdg->tdg_status)) {
kmp_node_info_t *source_info =
&task_sink->tdg->record_map[task_source->td_tdg_task_id];
bool exists = false;
for (int i = 0; i < source_info->nsuccessors; i++) {
if (source_info->successors[i] == task_sink->td_tdg_task_id) {
exists = true;
break;
}
}
if (!exists) {
if (source_info->nsuccessors >= source_info->successors_size) {
kmp_uint old_size = source_info->successors_size;
source_info->successors_size = 2 * source_info->successors_size;
kmp_int32 *old_succ_ids = source_info->successors;
kmp_int32 *new_succ_ids = (kmp_int32 *)__kmp_allocate(
source_info->successors_size * sizeof(kmp_int32));
KMP_MEMCPY(new_succ_ids, old_succ_ids, old_size * sizeof(kmp_int32));
source_info->successors = new_succ_ids;
__kmp_free(old_succ_ids);
}
source_info->successors[source_info->nsuccessors] =
task_sink->td_tdg_task_id;
source_info->nsuccessors++;
kmp_node_info_t *sink_info =
&(task_sink->tdg->record_map[task_sink->td_tdg_task_id]);
sink_info->npredecessors++;
}
}
#endif
#ifdef KMP_SUPPORT_GRAPH_OUTPUT
kmp_taskdata_t *task_source = KMP_TASK_TO_TASKDATA(source->dn.task);
// do not use sink->dn.task as that is only filled after the dependences
// are already processed!
kmp_taskdata_t *task_sink = KMP_TASK_TO_TASKDATA(sink_task);
__kmp_printf("%d(%s) -> %d(%s)\n", source->dn.id,
task_source->td_ident->psource, sink->dn.id,
task_sink->td_ident->psource);
#endif
#if OMPT_SUPPORT && OMPT_OPTIONAL
/* OMPT tracks dependences between task (a=source, b=sink) in which
task a blocks the execution of b through the ompt_new_dependence_callback
*/
if (ompt_enabled.ompt_callback_task_dependence) {
kmp_taskdata_t *task_source = KMP_TASK_TO_TASKDATA(source->dn.task);
ompt_data_t *sink_data;
if (sink_task)
sink_data = &(KMP_TASK_TO_TASKDATA(sink_task)->ompt_task_info.task_data);
else
sink_data = &__kmp_threads[gtid]->th.ompt_thread_info.task_data;
ompt_callbacks.ompt_callback(ompt_callback_task_dependence)(
&(task_source->ompt_task_info.task_data), sink_data);
}
#endif /* OMPT_SUPPORT && OMPT_OPTIONAL */
}
kmp_base_depnode_t *__kmpc_task_get_depnode(kmp_task_t *task) {
kmp_taskdata_t *td = KMP_TASK_TO_TASKDATA(task);
return td->td_depnode ? &(td->td_depnode->dn) : NULL;
}
kmp_depnode_list_t *__kmpc_task_get_successors(kmp_task_t *task) {
kmp_taskdata_t *td = KMP_TASK_TO_TASKDATA(task);
return td->td_depnode->dn.successors;
}
static inline kmp_int32
__kmp_depnode_link_successor(kmp_int32 gtid, kmp_info_t *thread,
kmp_task_t *task, kmp_depnode_t *node,
kmp_depnode_list_t *plist) {
if (!plist)
return 0;
kmp_int32 npredecessors = 0;
// link node as successor of list elements
for (kmp_depnode_list_t *p = plist; p; p = p->next) {
kmp_depnode_t *dep = p->node;
#if OMP_TASKGRAPH_EXPERIMENTAL
kmp_tdg_status tdg_status = KMP_TDG_NONE;
if (task) {
kmp_taskdata_t *td = KMP_TASK_TO_TASKDATA(task);
if (td->is_taskgraph)
tdg_status = KMP_TASK_TO_TASKDATA(task)->tdg->tdg_status;
if (__kmp_tdg_is_recording(tdg_status))
__kmp_track_dependence(gtid, dep, node, task);
}
#endif
if (dep->dn.task) {
KMP_ACQUIRE_DEPNODE(gtid, dep);
if (dep->dn.task) {
if (!dep->dn.successors || dep->dn.successors->node != node) {
#if OMP_TASKGRAPH_EXPERIMENTAL
if (!(__kmp_tdg_is_recording(tdg_status)) && task)
#endif
__kmp_track_dependence(gtid, dep, node, task);
dep->dn.successors = __kmp_add_node(thread, dep->dn.successors, node);
KA_TRACE(40, ("__kmp_process_deps: T#%d adding dependence from %p to "
"%p\n",
gtid, KMP_TASK_TO_TASKDATA(dep->dn.task),
KMP_TASK_TO_TASKDATA(task)));
npredecessors++;
}
}
KMP_RELEASE_DEPNODE(gtid, dep);
}
}
return npredecessors;
}
// Add the edge 'sink' -> 'source' in the task dependency graph
static inline kmp_int32 __kmp_depnode_link_successor(kmp_int32 gtid,
kmp_info_t *thread,
kmp_task_t *task,
kmp_depnode_t *source,
kmp_depnode_t *sink) {
if (!sink)
return 0;
kmp_int32 npredecessors = 0;
#if OMP_TASKGRAPH_EXPERIMENTAL
kmp_tdg_status tdg_status = KMP_TDG_NONE;
kmp_taskdata_t *td = KMP_TASK_TO_TASKDATA(task);
if (task) {
if (td->is_taskgraph)
tdg_status = KMP_TASK_TO_TASKDATA(task)->tdg->tdg_status;
if (__kmp_tdg_is_recording(tdg_status) && sink->dn.task)
__kmp_track_dependence(gtid, sink, source, task);
}
#endif
if (sink->dn.task) {
// synchronously add source to sink' list of successors
KMP_ACQUIRE_DEPNODE(gtid, sink);
if (sink->dn.task) {
if (!sink->dn.successors || sink->dn.successors->node != source) {
#if OMP_TASKGRAPH_EXPERIMENTAL
if (!(__kmp_tdg_is_recording(tdg_status)) && task)
#endif
__kmp_track_dependence(gtid, sink, source, task);
sink->dn.successors = __kmp_add_node(thread, sink->dn.successors, source);
KA_TRACE(40, ("__kmp_process_deps: T#%d adding dependence from %p to "
"%p\n",
gtid, KMP_TASK_TO_TASKDATA(sink->dn.task),
KMP_TASK_TO_TASKDATA(task)));
#if OMP_TASKGRAPH_EXPERIMENTAL
if (__kmp_tdg_is_recording(tdg_status)) {
kmp_taskdata_t *tdd = KMP_TASK_TO_TASKDATA(sink->dn.task);
if (tdd->is_taskgraph) {
if (tdd->td_flags.onced)
// decrement npredecessors if sink->dn.task belongs to a taskgraph
// and
// 1) the task is reset to its initial state (by kmp_free_task) or
// 2) the task is complete but not yet reset
npredecessors--;
}
}
#endif
npredecessors++;
}
}
KMP_RELEASE_DEPNODE(gtid, sink);
}
return npredecessors;
}
static inline kmp_int32
__kmp_process_dep_all(kmp_int32 gtid, kmp_depnode_t *node, kmp_dephash_t *h,
bool dep_barrier, kmp_task_t *task) {
KA_TRACE(30, ("__kmp_process_dep_all: T#%d processing dep_all, "
"dep_barrier = %d\n",
gtid, dep_barrier));
kmp_info_t *thread = __kmp_threads[gtid];
kmp_int32 npredecessors = 0;
// process previous omp_all_memory node if any
npredecessors +=
__kmp_depnode_link_successor(gtid, thread, task, node, h->last_all);
__kmp_node_deref(thread, h->last_all);
if (!dep_barrier) {
h->last_all = __kmp_node_ref(node);
} else {
// if this is a sync point in the serial sequence, then the previous
// outputs are guaranteed to be completed after the execution of this
// task so the previous output nodes can be cleared.
h->last_all = NULL;
}
// process all regular dependences
for (size_t i = 0; i < h->size; i++) {
kmp_dephash_entry_t *info = h->buckets[i];
if (!info) // skip empty slots in dephash
continue;
for (; info; info = info->next_in_bucket) {
// for each entry the omp_all_memory works as OUT dependence
kmp_depnode_t *last_out = info->last_out;
kmp_depnode_list_t *last_set = info->last_set;
kmp_depnode_list_t *prev_set = info->prev_set;
if (last_set) {
npredecessors +=
__kmp_depnode_link_successor(gtid, thread, task, node, last_set);
__kmp_depnode_list_free(thread, last_set);
__kmp_depnode_list_free(thread, prev_set);
info->last_set = NULL;
info->prev_set = NULL;
info->last_flag = 0; // no sets in this dephash entry
} else {
npredecessors +=
__kmp_depnode_link_successor(gtid, thread, task, node, last_out);
}
__kmp_node_deref(thread, last_out);
if (!dep_barrier) {
info->last_out = __kmp_node_ref(node);
} else {
info->last_out = NULL;
}
}
}
KA_TRACE(30, ("__kmp_process_dep_all: T#%d found %d predecessors\n", gtid,
npredecessors));
return npredecessors;
}
template <bool filter>
static inline kmp_int32
__kmp_process_deps(kmp_int32 gtid, kmp_depnode_t *node, kmp_dephash_t **hash,
bool dep_barrier, kmp_int32 ndeps,
kmp_depend_info_t *dep_list, kmp_task_t *task) {
KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d processing %d dependences : "
"dep_barrier = %d\n",
filter, gtid, ndeps, dep_barrier));
kmp_info_t *thread = __kmp_threads[gtid];
kmp_int32 npredecessors = 0;
for (kmp_int32 i = 0; i < ndeps; i++) {
const kmp_depend_info_t *dep = &dep_list[i];
if (filter && dep->base_addr == 0)
continue; // skip filtered entries
kmp_dephash_entry_t *info =
__kmp_dephash_find(thread, hash, dep->base_addr);
kmp_depnode_t *last_out = info->last_out;
kmp_depnode_list_t *last_set = info->last_set;
kmp_depnode_list_t *prev_set = info->prev_set;
if (dep->flags.out) { // out or inout --> clean lists if any
if (last_set) {
npredecessors +=
__kmp_depnode_link_successor(gtid, thread, task, node, last_set);
__kmp_depnode_list_free(thread, last_set);
__kmp_depnode_list_free(thread, prev_set);
info->last_set = NULL;
info->prev_set = NULL;
info->last_flag = 0; // no sets in this dephash entry
} else {
npredecessors +=
__kmp_depnode_link_successor(gtid, thread, task, node, last_out);
}
__kmp_node_deref(thread, last_out);
if (!dep_barrier) {
info->last_out = __kmp_node_ref(node);
} else {
// if this is a sync point in the serial sequence, then the previous
// outputs are guaranteed to be completed after the execution of this
// task so the previous output nodes can be cleared.
info->last_out = NULL;
}
} else { // either IN or MTX or SET
if (info->last_flag == 0 || info->last_flag == dep->flag) {
// last_set either didn't exist or of same dep kind
// link node as successor of the last_out if any
npredecessors +=
__kmp_depnode_link_successor(gtid, thread, task, node, last_out);
// link node as successor of all nodes in the prev_set if any
npredecessors +=
__kmp_depnode_link_successor(gtid, thread, task, node, prev_set);
if (dep_barrier) {
// clean last_out and prev_set if any; don't touch last_set
__kmp_node_deref(thread, last_out);
info->last_out = NULL;
__kmp_depnode_list_free(thread, prev_set);
info->prev_set = NULL;
}
} else { // last_set is of different dep kind, make it prev_set
// link node as successor of all nodes in the last_set
npredecessors +=
__kmp_depnode_link_successor(gtid, thread, task, node, last_set);
// clean last_out if any
__kmp_node_deref(thread, last_out);
info->last_out = NULL;
// clean prev_set if any
__kmp_depnode_list_free(thread, prev_set);
if (!dep_barrier) {
// move last_set to prev_set, new last_set will be allocated
info->prev_set = last_set;
} else {
info->prev_set = NULL;
info->last_flag = 0;
}
info->last_set = NULL;
}
// for dep_barrier last_flag value should remain:
// 0 if last_set is empty, unchanged otherwise
if (!dep_barrier) {
info->last_flag = dep->flag; // store dep kind of the last_set
info->last_set = __kmp_add_node(thread, info->last_set, node);
}
// check if we are processing MTX dependency
if (dep->flag == KMP_DEP_MTX) {
if (info->mtx_lock == NULL) {
info->mtx_lock = (kmp_lock_t *)__kmp_allocate(sizeof(kmp_lock_t));
__kmp_init_lock(info->mtx_lock);
}
KMP_DEBUG_ASSERT(node->dn.mtx_num_locks < MAX_MTX_DEPS);
kmp_int32 m;
// Save lock in node's array
for (m = 0; m < MAX_MTX_DEPS; ++m) {
// sort pointers in decreasing order to avoid potential livelock
if (node->dn.mtx_locks[m] < info->mtx_lock) {
KMP_DEBUG_ASSERT(!node->dn.mtx_locks[node->dn.mtx_num_locks]);
for (int n = node->dn.mtx_num_locks; n > m; --n) {
// shift right all lesser non-NULL pointers
KMP_DEBUG_ASSERT(node->dn.mtx_locks[n - 1] != NULL);
node->dn.mtx_locks[n] = node->dn.mtx_locks[n - 1];
}
node->dn.mtx_locks[m] = info->mtx_lock;
break;
}
}
KMP_DEBUG_ASSERT(m < MAX_MTX_DEPS); // must break from loop
node->dn.mtx_num_locks++;
}
}
}
KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d found %d predecessors\n", filter,
gtid, npredecessors));
return npredecessors;
}
#define NO_DEP_BARRIER (false)
#define DEP_BARRIER (true)
// returns true if the task has any outstanding dependence
static bool __kmp_check_deps(kmp_int32 gtid, kmp_depnode_t *node,
kmp_task_t *task, kmp_dephash_t **hash,
bool dep_barrier, kmp_int32 ndeps,
kmp_depend_info_t *dep_list,
kmp_int32 ndeps_noalias,
kmp_depend_info_t *noalias_dep_list) {
int i, n_mtxs = 0, dep_all = 0;
#if KMP_DEBUG
kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
#endif
KA_TRACE(20, ("__kmp_check_deps: T#%d checking dependences for task %p : %d "
"possibly aliased dependences, %d non-aliased dependences : "
"dep_barrier=%d .\n",
gtid, taskdata, ndeps, ndeps_noalias, dep_barrier));
// Filter deps in dep_list
// TODO: Different algorithm for large dep_list ( > 10 ? )
for (i = 0; i < ndeps; i++) {
if (dep_list[i].base_addr != 0 &&
dep_list[i].base_addr != (kmp_intptr_t)KMP_SIZE_T_MAX) {
KMP_DEBUG_ASSERT(
dep_list[i].flag == KMP_DEP_IN || dep_list[i].flag == KMP_DEP_OUT ||
dep_list[i].flag == KMP_DEP_INOUT ||
dep_list[i].flag == KMP_DEP_MTX || dep_list[i].flag == KMP_DEP_SET);
for (int j = i + 1; j < ndeps; j++) {
if (dep_list[i].base_addr == dep_list[j].base_addr) {
if (dep_list[i].flag != dep_list[j].flag) {
// two different dependences on same address work identical to OUT
dep_list[i].flag = KMP_DEP_OUT;
}
dep_list[j].base_addr = 0; // Mark j element as void
}
}
if (dep_list[i].flag == KMP_DEP_MTX) {
// limit number of mtx deps to MAX_MTX_DEPS per node
if (n_mtxs < MAX_MTX_DEPS && task != NULL) {
++n_mtxs;
} else {
dep_list[i].flag = KMP_DEP_OUT; // downgrade mutexinoutset to inout
}
}
} else if (dep_list[i].flag == KMP_DEP_ALL ||
dep_list[i].base_addr == (kmp_intptr_t)KMP_SIZE_T_MAX) {
// omp_all_memory dependence can be marked by compiler by either
// (addr=0 && flag=0x80) (flag KMP_DEP_ALL), or (addr=-1).
// omp_all_memory overrides all other dependences if any
dep_all = 1;
break;
}
}
// doesn't need to be atomic as no other thread is going to be accessing this
// node just yet.
// npredecessors is set -1 to ensure that none of the releasing tasks queues
// this task before we have finished processing all the dependences
node->dn.npredecessors = -1;
// used to pack all npredecessors additions into a single atomic operation at
// the end
int npredecessors;
if (!dep_all) { // regular dependences
npredecessors = __kmp_process_deps<true>(gtid, node, hash, dep_barrier,
ndeps, dep_list, task);
npredecessors += __kmp_process_deps<false>(
gtid, node, hash, dep_barrier, ndeps_noalias, noalias_dep_list, task);
} else { // omp_all_memory dependence
npredecessors = __kmp_process_dep_all(gtid, node, *hash, dep_barrier, task);
}
node->dn.task = task;
KMP_MB();
// Account for our initial fake value
npredecessors++;
// Update predecessors and obtain current value to check if there are still
// any outstanding dependences (some tasks may have finished while we
// processed the dependences)
npredecessors =
node->dn.npredecessors.fetch_add(npredecessors) + npredecessors;
KA_TRACE(20, ("__kmp_check_deps: T#%d found %d predecessors for task %p \n",
gtid, npredecessors, taskdata));
// beyond this point the task could be queued (and executed) by a releasing
// task...
return npredecessors > 0 ? true : false;
}
/*!
@ingroup TASKING
@param loc_ref location of the original task directive
@param gtid Global Thread ID of encountering thread
@param new_task task thunk allocated by __kmp_omp_task_alloc() for the ''new
task''
@param ndeps Number of depend items with possible aliasing
@param dep_list List of depend items with possible aliasing
@param ndeps_noalias Number of depend items with no aliasing
@param noalias_dep_list List of depend items with no aliasing
@return Returns either TASK_CURRENT_NOT_QUEUED if the current task was not
suspended and queued, or TASK_CURRENT_QUEUED if it was suspended and queued
Schedule a non-thread-switchable task with dependences for execution
*/
kmp_int32 __kmpc_omp_task_with_deps(ident_t *loc_ref, kmp_int32 gtid,
kmp_task_t *new_task, kmp_int32 ndeps,
kmp_depend_info_t *dep_list,
kmp_int32 ndeps_noalias,
kmp_depend_info_t *noalias_dep_list) {
kmp_taskdata_t *new_taskdata = KMP_TASK_TO_TASKDATA(new_task);
KA_TRACE(10, ("__kmpc_omp_task_with_deps(enter): T#%d loc=%p task=%p\n", gtid,
loc_ref, new_taskdata));
__kmp_assert_valid_gtid(gtid);
kmp_info_t *thread = __kmp_threads[gtid];
kmp_taskdata_t *current_task = thread->th.th_current_task;
#if OMP_TASKGRAPH_EXPERIMENTAL
// record TDG with deps
if (new_taskdata->is_taskgraph &&
__kmp_tdg_is_recording(new_taskdata->tdg->tdg_status)) {
kmp_tdg_info_t *tdg = new_taskdata->tdg;
// extend record_map if needed
if (new_taskdata->td_tdg_task_id >= tdg->map_size) {
__kmp_acquire_bootstrap_lock(&tdg->graph_lock);
if (new_taskdata->td_tdg_task_id >= tdg->map_size) {
kmp_uint old_size = tdg->map_size;
kmp_uint new_size = old_size * 2;
kmp_node_info_t *old_record = tdg->record_map;
kmp_node_info_t *new_record = (kmp_node_info_t *)__kmp_allocate(
new_size * sizeof(kmp_node_info_t));
KMP_MEMCPY(new_record, tdg->record_map,
old_size * sizeof(kmp_node_info_t));
tdg->record_map = new_record;
__kmp_free(old_record);
for (kmp_uint i = old_size; i < new_size; i++) {
kmp_int32 *successorsList = (kmp_int32 *)__kmp_allocate(
__kmp_successors_size * sizeof(kmp_int32));
new_record[i].task = nullptr;
new_record[i].successors = successorsList;
new_record[i].nsuccessors = 0;
new_record[i].npredecessors = 0;
new_record[i].successors_size = __kmp_successors_size;
KMP_ATOMIC_ST_REL(&new_record[i].npredecessors_counter, 0);
}
// update the size at the end, so that we avoid other
// threads use old_record while map_size is already updated
tdg->map_size = new_size;
}
__kmp_release_bootstrap_lock(&tdg->graph_lock);
}
tdg->record_map[new_taskdata->td_tdg_task_id].task = new_task;
tdg->record_map[new_taskdata->td_tdg_task_id].parent_task =
new_taskdata->td_parent;
KMP_ATOMIC_INC(&tdg->num_tasks);
}
#endif
#if OMPT_SUPPORT
if (ompt_enabled.enabled) {
if (!current_task->ompt_task_info.frame.enter_frame.ptr)
current_task->ompt_task_info.frame.enter_frame.ptr =
OMPT_GET_FRAME_ADDRESS(0);
if (ompt_enabled.ompt_callback_task_create) {
ompt_callbacks.ompt_callback(ompt_callback_task_create)(
&(current_task->ompt_task_info.task_data),
&(current_task->ompt_task_info.frame),
&(new_taskdata->ompt_task_info.task_data),
TASK_TYPE_DETAILS_FORMAT(new_taskdata), 1,
OMPT_LOAD_OR_GET_RETURN_ADDRESS(gtid));
}
new_taskdata->ompt_task_info.frame.enter_frame.ptr =
OMPT_GET_FRAME_ADDRESS(0);
}
#if OMPT_OPTIONAL
/* OMPT grab all dependences if requested by the tool */
if (ndeps + ndeps_noalias > 0 && ompt_enabled.ompt_callback_dependences) {
kmp_int32 i;
int ompt_ndeps = ndeps + ndeps_noalias;
ompt_dependence_t *ompt_deps = (ompt_dependence_t *)KMP_OMPT_DEPS_ALLOC(
thread, (ndeps + ndeps_noalias) * sizeof(ompt_dependence_t));
KMP_ASSERT(ompt_deps != NULL);
for (i = 0; i < ndeps; i++) {
ompt_deps[i].variable.ptr = (void *)dep_list[i].base_addr;
if (dep_list[i].base_addr == (kmp_intptr_t)KMP_SIZE_T_MAX)
ompt_deps[i].dependence_type = ompt_dependence_type_out_all_memory;
else if (dep_list[i].flags.in && dep_list[i].flags.out)
ompt_deps[i].dependence_type = ompt_dependence_type_inout;
else if (dep_list[i].flags.out)
ompt_deps[i].dependence_type = ompt_dependence_type_out;
else if (dep_list[i].flags.in)
ompt_deps[i].dependence_type = ompt_dependence_type_in;
else if (dep_list[i].flags.mtx)
ompt_deps[i].dependence_type = ompt_dependence_type_mutexinoutset;
else if (dep_list[i].flags.set)
ompt_deps[i].dependence_type = ompt_dependence_type_inoutset;
else if (dep_list[i].flags.all)
ompt_deps[i].dependence_type = ompt_dependence_type_out_all_memory;
}
for (i = 0; i < ndeps_noalias; i++) {
ompt_deps[ndeps + i].variable.ptr = (void *)noalias_dep_list[i].base_addr;
if (noalias_dep_list[i].base_addr == (kmp_intptr_t)KMP_SIZE_T_MAX)
ompt_deps[ndeps + i].dependence_type =
ompt_dependence_type_out_all_memory;
else if (noalias_dep_list[i].flags.in && noalias_dep_list[i].flags.out)
ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inout;
else if (noalias_dep_list[i].flags.out)
ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_out;
else if (noalias_dep_list[i].flags.in)
ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_in;
else if (noalias_dep_list[i].flags.mtx)
ompt_deps[ndeps + i].dependence_type =
ompt_dependence_type_mutexinoutset;
else if (noalias_dep_list[i].flags.set)
ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inoutset;
else if (noalias_dep_list[i].flags.all)
ompt_deps[ndeps + i].dependence_type =
ompt_dependence_type_out_all_memory;
}
ompt_callbacks.ompt_callback(ompt_callback_dependences)(
&(new_taskdata->ompt_task_info.task_data), ompt_deps, ompt_ndeps);
/* We can now free the allocated memory for the dependences */
/* For OMPD we might want to delay the free until end of this function */
KMP_OMPT_DEPS_FREE(thread, ompt_deps);
}
#endif /* OMPT_OPTIONAL */
#endif /* OMPT_SUPPORT */
bool serial = current_task->td_flags.team_serial ||
current_task->td_flags.tasking_ser ||
current_task->td_flags.final;
kmp_task_team_t *task_team = thread->th.th_task_team;
serial = serial &&
!(task_team && (task_team->tt.tt_found_proxy_tasks ||
task_team->tt.tt_hidden_helper_task_encountered));
if (!serial && (ndeps > 0 || ndeps_noalias > 0)) {
/* if no dependences have been tracked yet, create the dependence hash */
if (current_task->td_dephash == NULL)
current_task->td_dephash = __kmp_dephash_create(thread, current_task);
#if USE_FAST_MEMORY
kmp_depnode_t *node =
(kmp_depnode_t *)__kmp_fast_allocate(thread, sizeof(kmp_depnode_t));
#else
kmp_depnode_t *node =
(kmp_depnode_t *)__kmp_thread_malloc(thread, sizeof(kmp_depnode_t));
#endif
__kmp_init_node(node, /*on_stack=*/false);
new_taskdata->td_depnode = node;
if (__kmp_check_deps(gtid, node, new_task, &current_task->td_dephash,
NO_DEP_BARRIER, ndeps, dep_list, ndeps_noalias,
noalias_dep_list)) {
KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had blocking "
"dependences: "
"loc=%p task=%p, return: TASK_CURRENT_NOT_QUEUED\n",
gtid, loc_ref, new_taskdata));
#if OMPT_SUPPORT
if (ompt_enabled.enabled) {
current_task->ompt_task_info.frame.enter_frame = ompt_data_none;
}
#endif
return TASK_CURRENT_NOT_QUEUED;
}
} else {
KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d ignored dependences "
"for task (serialized) loc=%p task=%p\n",
gtid, loc_ref, new_taskdata));
}
KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had no blocking "
"dependences : "
"loc=%p task=%p, transferring to __kmp_omp_task\n",
gtid, loc_ref, new_taskdata));
kmp_int32 ret = __kmp_omp_task(gtid, new_task, true);
#if OMPT_SUPPORT
if (ompt_enabled.enabled) {
current_task->ompt_task_info.frame.enter_frame = ompt_data_none;
}
#endif
return ret;
}
#if OMPT_SUPPORT
void __ompt_taskwait_dep_finish(kmp_taskdata_t *current_task,
ompt_data_t *taskwait_task_data) {
if (ompt_enabled.ompt_callback_task_schedule) {
ompt_callbacks.ompt_callback(ompt_callback_task_schedule)(
taskwait_task_data, ompt_taskwait_complete, NULL);
}
current_task->ompt_task_info.frame.enter_frame.ptr = NULL;
*taskwait_task_data = ompt_data_none;
}
#endif /* OMPT_SUPPORT */
/*!
@ingroup TASKING
@param loc_ref location of the original task directive
@param gtid Global Thread ID of encountering thread
@param ndeps Number of depend items with possible aliasing
@param dep_list List of depend items with possible aliasing
@param ndeps_noalias Number of depend items with no aliasing
@param noalias_dep_list List of depend items with no aliasing
Blocks the current task until all specifies dependences have been fulfilled.
*/
void __kmpc_omp_wait_deps(ident_t *loc_ref, kmp_int32 gtid, kmp_int32 ndeps,
kmp_depend_info_t *dep_list, kmp_int32 ndeps_noalias,
kmp_depend_info_t *noalias_dep_list) {
__kmpc_omp_taskwait_deps_51(loc_ref, gtid, ndeps, dep_list, ndeps_noalias,
noalias_dep_list, false);
}
/* __kmpc_omp_taskwait_deps_51 : Function for OpenMP 5.1 nowait clause.
Placeholder for taskwait with nowait clause.
Earlier code of __kmpc_omp_wait_deps() is now
in this function.
*/
void __kmpc_omp_taskwait_deps_51(ident_t *loc_ref, kmp_int32 gtid,
kmp_int32 ndeps, kmp_depend_info_t *dep_list,
kmp_int32 ndeps_noalias,
kmp_depend_info_t *noalias_dep_list,
kmp_int32 has_no_wait) {
KA_TRACE(10, ("__kmpc_omp_taskwait_deps(enter): T#%d loc=%p nowait#%d\n",
gtid, loc_ref, has_no_wait));
if (ndeps == 0 && ndeps_noalias == 0) {
KA_TRACE(10, ("__kmpc_omp_taskwait_deps(exit): T#%d has no dependences to "
"wait upon : loc=%p\n",
gtid, loc_ref));
return;
}
__kmp_assert_valid_gtid(gtid);
kmp_info_t *thread = __kmp_threads[gtid];
kmp_taskdata_t *current_task = thread->th.th_current_task;
#if OMPT_SUPPORT
// this function represents a taskwait construct with depend clause
// We signal 4 events:
// - creation of the taskwait task
// - dependences of the taskwait task
// - schedule and finish of the taskwait task
ompt_data_t *taskwait_task_data = &thread->th.ompt_thread_info.task_data;
KMP_ASSERT(taskwait_task_data->ptr == NULL);
if (ompt_enabled.enabled) {
if (!current_task->ompt_task_info.frame.enter_frame.ptr)
current_task->ompt_task_info.frame.enter_frame.ptr =
OMPT_GET_FRAME_ADDRESS(0);
if (ompt_enabled.ompt_callback_task_create) {
ompt_callbacks.ompt_callback(ompt_callback_task_create)(
&(current_task->ompt_task_info.task_data),
&(current_task->ompt_task_info.frame), taskwait_task_data,
ompt_task_taskwait | ompt_task_undeferred | ompt_task_mergeable, 1,
OMPT_LOAD_OR_GET_RETURN_ADDRESS(gtid));
}
}
#if OMPT_OPTIONAL
/* OMPT grab all dependences if requested by the tool */
if (ndeps + ndeps_noalias > 0 && ompt_enabled.ompt_callback_dependences) {
kmp_int32 i;
int ompt_ndeps = ndeps + ndeps_noalias;
ompt_dependence_t *ompt_deps = (ompt_dependence_t *)KMP_OMPT_DEPS_ALLOC(
thread, (ndeps + ndeps_noalias) * sizeof(ompt_dependence_t));
KMP_ASSERT(ompt_deps != NULL);
for (i = 0; i < ndeps; i++) {
ompt_deps[i].variable.ptr = (void *)dep_list[i].base_addr;
if (dep_list[i].flags.in && dep_list[i].flags.out)
ompt_deps[i].dependence_type = ompt_dependence_type_inout;
else if (dep_list[i].flags.out)
ompt_deps[i].dependence_type = ompt_dependence_type_out;
else if (dep_list[i].flags.in)
ompt_deps[i].dependence_type = ompt_dependence_type_in;
else if (dep_list[i].flags.mtx)
ompt_deps[ndeps + i].dependence_type =
ompt_dependence_type_mutexinoutset;
else if (dep_list[i].flags.set)
ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inoutset;
}
for (i = 0; i < ndeps_noalias; i++) {
ompt_deps[ndeps + i].variable.ptr = (void *)noalias_dep_list[i].base_addr;
if (noalias_dep_list[i].flags.in && noalias_dep_list[i].flags.out)
ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inout;
else if (noalias_dep_list[i].flags.out)
ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_out;
else if (noalias_dep_list[i].flags.in)
ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_in;
else if (noalias_dep_list[i].flags.mtx)
ompt_deps[ndeps + i].dependence_type =
ompt_dependence_type_mutexinoutset;
else if (noalias_dep_list[i].flags.set)
ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inoutset;
}
ompt_callbacks.ompt_callback(ompt_callback_dependences)(
taskwait_task_data, ompt_deps, ompt_ndeps);
/* We can now free the allocated memory for the dependences */
/* For OMPD we might want to delay the free until end of this function */
KMP_OMPT_DEPS_FREE(thread, ompt_deps);
ompt_deps = NULL;
}
#endif /* OMPT_OPTIONAL */
#endif /* OMPT_SUPPORT */
// We can return immediately as:
// - dependences are not computed in serial teams (except with proxy tasks)
// - if the dephash is not yet created it means we have nothing to wait for
bool ignore = current_task->td_flags.team_serial ||
current_task->td_flags.tasking_ser ||
current_task->td_flags.final;
ignore =
ignore && thread->th.th_task_team != NULL &&
thread->th.th_task_team->tt.tt_found_proxy_tasks == FALSE &&
thread->th.th_task_team->tt.tt_hidden_helper_task_encountered == FALSE;
ignore = ignore || current_task->td_dephash == NULL;
if (ignore) {
KA_TRACE(10, ("__kmpc_omp_taskwait_deps(exit): T#%d has no blocking "
"dependences : loc=%p\n",
gtid, loc_ref));
#if OMPT_SUPPORT
__ompt_taskwait_dep_finish(current_task, taskwait_task_data);
#endif /* OMPT_SUPPORT */
return;
}
kmp_depnode_t node = {0};
__kmp_init_node(&node, /*on_stack=*/true);
if (!__kmp_check_deps(gtid, &node, NULL, &current_task->td_dephash,
DEP_BARRIER, ndeps, dep_list, ndeps_noalias,
noalias_dep_list)) {
KA_TRACE(10, ("__kmpc_omp_taskwait_deps(exit): T#%d has no blocking "
"dependences : loc=%p\n",
gtid, loc_ref));
#if OMPT_SUPPORT
__ompt_taskwait_dep_finish(current_task, taskwait_task_data);
#endif /* OMPT_SUPPORT */
// There may still be references to this node here, due to task stealing.
// Wait for them to be released.
kmp_int32 nrefs;
while ((nrefs = node.dn.nrefs) > 3) {
KMP_DEBUG_ASSERT((nrefs & 1) == 1);
KMP_YIELD(TRUE);
}
KMP_DEBUG_ASSERT(nrefs == 3);
return;
}
int thread_finished = FALSE;
kmp_flag_32<false, false> flag(
(std::atomic<kmp_uint32> *)&node.dn.npredecessors, 0U);
while (node.dn.npredecessors > 0) {
flag.execute_tasks(thread, gtid, FALSE,
&thread_finished USE_ITT_BUILD_ARG(NULL),
__kmp_task_stealing_constraint);
}
// Wait until the last __kmp_release_deps is finished before we free the
// current stack frame holding the "node" variable; once its nrefs count
// reaches 3 (meaning 1, since bit zero of the refcount indicates a stack
// rather than a heap address), we're sure nobody else can try to reference
// it again.
kmp_int32 nrefs;
while ((nrefs = node.dn.nrefs) > 3) {
KMP_DEBUG_ASSERT((nrefs & 1) == 1);
KMP_YIELD(TRUE);
}
KMP_DEBUG_ASSERT(nrefs == 3);
#if OMPT_SUPPORT
__ompt_taskwait_dep_finish(current_task, taskwait_task_data);
#endif /* OMPT_SUPPORT */
KA_TRACE(10, ("__kmpc_omp_taskwait_deps(exit): T#%d finished waiting : loc=%p\
\n",
gtid, loc_ref));
}