diff options
Diffstat (limited to 'rc3/runtime/src/kmp_taskdeps.cpp')
| -rw-r--r-- | rc3/runtime/src/kmp_taskdeps.cpp | 664 |
1 files changed, 664 insertions, 0 deletions
diff --git a/rc3/runtime/src/kmp_taskdeps.cpp b/rc3/runtime/src/kmp_taskdeps.cpp new file mode 100644 index 0000000..fcdd632 --- /dev/null +++ b/rc3/runtime/src/kmp_taskdeps.cpp @@ -0,0 +1,664 @@ +/* + * kmp_taskdeps.cpp + */ + +//===----------------------------------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is dual licensed under the MIT and the University of Illinois Open +// Source Licenses. See LICENSE.txt for details. +// +//===----------------------------------------------------------------------===// + +//#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 + +#if OMP_40_ENABLED + +// 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 = ATOMIC_VAR_INIT(0); +#endif + +static void __kmp_init_node(kmp_depnode_t *node) { + node->dn.successors = NULL; + node->dn.task = NULL; // will point to the rigth 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); + KMP_ATOMIC_ST_RLX(&node->dn.nrefs, 1); // init creates the first reference +#ifdef KMP_SUPPORT_GRAPH_OUTPUT + node->dn.id = KMP_ATOMIC_INC(&kmp_node_id_seed); +#endif +} + +static inline kmp_depnode_t *__kmp_node_ref(kmp_depnode_t *node) { + KMP_ATOMIC_INC(&node->dn.nrefs); + return node; +} + +enum { KMP_DEPHASH_OTHER_SIZE = 97, KMP_DEPHASH_MASTER_SIZE = 997 }; + +static inline kmp_int32 __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_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; + + kmp_int32 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; + +#ifdef KMP_DEBUG + h->nelements = 0; + h->nconflicts = 0; +#endif + h->buckets = (kmp_dephash_entry **)(h + 1); + + for (size_t i = 0; i < h_size; i++) + h->buckets[i] = 0; + + return h; +} + +#define ENTRY_LAST_INS 0 +#define ENTRY_LAST_MTXS 1 + +static kmp_dephash_entry * +__kmp_dephash_find(kmp_info_t *thread, kmp_dephash_t *h, kmp_intptr_t addr) { + kmp_int32 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; + entry->last_out = NULL; + entry->last_ins = NULL; + entry->last_mtxs = NULL; + entry->last_flag = ENTRY_LAST_INS; + entry->mtx_lock = NULL; + entry->next_in_bucket = h->buckets[bucket]; + h->buckets[bucket] = entry; +#ifdef KMP_DEBUG + h->nelements++; + if (entry->next_in_bucket) + h->nconflicts++; +#endif + } + 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_depnode_t *source, + kmp_depnode_t *sink, + kmp_task_t *sink_task) { +#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 dependencies + // 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); + kmp_taskdata_t *task_sink = KMP_TASK_TO_TASKDATA(sink_task); + + ompt_callbacks.ompt_callback(ompt_callback_task_dependence)( + &(task_source->ompt_task_info.task_data), + &(task_sink->ompt_task_info.task_data)); + } +#endif /* OMPT_SUPPORT && OMPT_OPTIONAL */ +} + +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 (dep->dn.task) { + KMP_ACQUIRE_DEPNODE(gtid, dep); + if (dep->dn.task) { + __kmp_track_dependence(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; +} + +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 (sink->dn.task) { + // synchronously add source to sink' list of successors + KMP_ACQUIRE_DEPNODE(gtid, sink); + if (sink->dn.task) { + __kmp_track_dependence(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))); + npredecessors++; + } + KMP_RELEASE_DEPNODE(gtid, sink); + } + 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 dependencies : " + "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_ins = info->last_ins; + kmp_depnode_list_t *last_mtxs = info->last_mtxs; + + if (dep->flags.out) { // out --> clean lists of ins and mtxs if any + if (last_ins || last_mtxs) { + if (info->last_flag == ENTRY_LAST_INS) { // INS were last + npredecessors += + __kmp_depnode_link_successor(gtid, thread, task, node, last_ins); + } else { // MTXS were last + npredecessors += + __kmp_depnode_link_successor(gtid, thread, task, node, last_mtxs); + } + __kmp_depnode_list_free(thread, last_ins); + __kmp_depnode_list_free(thread, last_mtxs); + info->last_ins = NULL; + info->last_mtxs = NULL; + } else { + npredecessors += + __kmp_depnode_link_successor(gtid, thread, task, node, last_out); + } + __kmp_node_deref(thread, last_out); + if (dep_barrier) { + // 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 { + info->last_out = __kmp_node_ref(node); + } + } else if (dep->flags.in) { + // in --> link node to either last_out or last_mtxs, clean earlier deps + if (last_mtxs) { + npredecessors += + __kmp_depnode_link_successor(gtid, thread, task, node, last_mtxs); + __kmp_node_deref(thread, last_out); + info->last_out = NULL; + if (info->last_flag == ENTRY_LAST_MTXS && last_ins) { // MTXS were last + // clean old INS before creating new list + __kmp_depnode_list_free(thread, last_ins); + info->last_ins = NULL; + } + } else { + // link node as successor of the last_out if any + npredecessors += + __kmp_depnode_link_successor(gtid, thread, task, node, last_out); + } + info->last_flag = ENTRY_LAST_INS; + info->last_ins = __kmp_add_node(thread, info->last_ins, node); + } else { + KMP_DEBUG_ASSERT(dep->flags.mtx == 1); + // mtx --> link node to either last_out or last_ins, clean earlier deps + if (last_ins) { + npredecessors += + __kmp_depnode_link_successor(gtid, thread, task, node, last_ins); + __kmp_node_deref(thread, last_out); + info->last_out = NULL; + if (info->last_flag == ENTRY_LAST_INS && last_mtxs) { // INS were last + // clean old MTXS before creating new list + __kmp_depnode_list_free(thread, last_mtxs); + info->last_mtxs = NULL; + } + } else { + // link node as successor of the last_out if any + npredecessors += + __kmp_depnode_link_successor(gtid, thread, task, node, last_out); + } + info->last_flag = ENTRY_LAST_MTXS; + info->last_mtxs = __kmp_add_node(thread, info->last_mtxs, node); + 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] == NULL); + 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; +#if KMP_DEBUG + kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task); +#endif + KA_TRACE(20, ("__kmp_check_deps: T#%d checking dependencies for task %p : %d " + "possibly aliased dependencies, %d non-aliased depedencies : " + "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) { + for (int j = i + 1; j < ndeps; j++) { + if (dep_list[i].base_addr == dep_list[j].base_addr) { + dep_list[i].flags.in |= dep_list[j].flags.in; + dep_list[i].flags.out |= + (dep_list[j].flags.out || + (dep_list[i].flags.in && dep_list[j].flags.mtx) || + (dep_list[i].flags.mtx && dep_list[j].flags.in)); + dep_list[i].flags.mtx = + dep_list[i].flags.mtx | dep_list[j].flags.mtx && + !dep_list[i].flags.out; + dep_list[j].base_addr = 0; // Mark j element as void + } + } + if (dep_list[i].flags.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].flags.in = 1; // downgrade mutexinoutset to inout + dep_list[i].flags.out = 1; + dep_list[i].flags.mtx = 0; + } + } + } + } + + // 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 dependencies + node->dn.npredecessors = -1; + + // used to pack all npredecessors additions into a single atomic operation at + // the end + int npredecessors; + + 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); + + 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 outstandig 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 +suspendend 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_info_t *thread = __kmp_threads[gtid]; + kmp_taskdata_t *current_task = thread->th.th_current_task; + +#if OMPT_SUPPORT + if (ompt_enabled.enabled) { + OMPT_STORE_RETURN_ADDRESS(gtid); + 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_data_t task_data = ompt_data_none; + ompt_callbacks.ompt_callback(ompt_callback_task_create)( + current_task ? &(current_task->ompt_task_info.task_data) : &task_data, + current_task ? &(current_task->ompt_task_info.frame) : NULL, + &(new_taskdata->ompt_task_info.task_data), + ompt_task_explicit | TASK_TYPE_DETAILS_FORMAT(new_taskdata), 1, + OMPT_LOAD_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; + + new_taskdata->ompt_task_info.ndeps = ndeps + ndeps_noalias; + new_taskdata->ompt_task_info.deps = + (ompt_dependence_t *)KMP_OMPT_DEPS_ALLOC( + thread, (ndeps + ndeps_noalias) * sizeof(ompt_dependence_t)); + + KMP_ASSERT(new_taskdata->ompt_task_info.deps != NULL); + + for (i = 0; i < ndeps; i++) { + new_taskdata->ompt_task_info.deps[i].variable.ptr = + (void *)dep_list[i].base_addr; + if (dep_list[i].flags.in && dep_list[i].flags.out) + new_taskdata->ompt_task_info.deps[i].dependence_type = + ompt_dependence_type_inout; + else if (dep_list[i].flags.out) + new_taskdata->ompt_task_info.deps[i].dependence_type = + ompt_dependence_type_out; + else if (dep_list[i].flags.in) + new_taskdata->ompt_task_info.deps[i].dependence_type = + ompt_dependence_type_in; + } + for (i = 0; i < ndeps_noalias; i++) { + new_taskdata->ompt_task_info.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) + new_taskdata->ompt_task_info.deps[ndeps + i].dependence_type = + ompt_dependence_type_inout; + else if (noalias_dep_list[i].flags.out) + new_taskdata->ompt_task_info.deps[ndeps + i].dependence_type = + ompt_dependence_type_out; + else if (noalias_dep_list[i].flags.in) + new_taskdata->ompt_task_info.deps[ndeps + i].dependence_type = + ompt_dependence_type_in; + } + ompt_callbacks.ompt_callback(ompt_callback_dependences)( + &(new_taskdata->ompt_task_info.task_data), + new_taskdata->ompt_task_info.deps, new_taskdata->ompt_task_info.ndeps); + /* We can now free the allocated memory for the dependencies */ + /* For OMPD we might want to delay the free until task_end */ + KMP_OMPT_DEPS_FREE(thread, new_taskdata->ompt_task_info.deps); + new_taskdata->ompt_task_info.deps = NULL; + new_taskdata->ompt_task_info.ndeps = 0; + } +#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; +#if OMP_45_ENABLED + kmp_task_team_t *task_team = thread->th.th_task_team; + serial = serial && !(task_team && task_team->tt.tt_found_proxy_tasks); +#endif + + if (!serial && (ndeps > 0 || ndeps_noalias > 0)) { + /* if no dependencies 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); + 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 " + "dependencies: " + "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 dependencies " + "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 " + "dependencies : " + "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; +} + +/*! +@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 dependencies 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) { + KA_TRACE(10, ("__kmpc_omp_wait_deps(enter): T#%d loc=%p\n", gtid, loc_ref)); + + if (ndeps == 0 && ndeps_noalias == 0) { + KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no dependencies to " + "wait upon : loc=%p\n", + gtid, loc_ref)); + return; + } + + kmp_info_t *thread = __kmp_threads[gtid]; + kmp_taskdata_t *current_task = thread->th.th_current_task; + + // 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; +#if OMP_45_ENABLED + ignore = ignore && thread->th.th_task_team != NULL && + thread->th.th_task_team->tt.tt_found_proxy_tasks == FALSE; +#endif + ignore = ignore || current_task->td_dephash == NULL; + + if (ignore) { + KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking " + "dependencies : loc=%p\n", + gtid, loc_ref)); + return; + } + + kmp_depnode_t node = {0}; + __kmp_init_node(&node); + + 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_wait_deps(exit): T#%d has no blocking " + "dependencies : loc=%p\n", + gtid, loc_ref)); + return; + } + + int thread_finished = FALSE; + kmp_flag_32 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); + } + + KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d finished waiting : loc=%p\n", + gtid, loc_ref)); +} + +#endif /* OMP_40_ENABLED */ |