D9306 omp 4.1 async offload support (partial): code changes

llvm-svn: 236753
2015-05-07 17:41:51 +00:00 · 2015-05-07 17:41:51 +00:00 · 535b6faaf0
parent d9d900c05b
commit 535b6faaf0
7 changed files with 426 additions and 23 deletions
--- a/openmp/runtime/src/dllexports
+++ b/openmp/runtime/src/dllexports
@ -381,6 +381,14 @@ kmpc_set_defaults                           224
    %endif # OMP_40
 %endif

+# OpenMP 4.1 entry points
+%ifndef stub
+    %ifdef OMP_41
+	__kmpc_proxy_task_completed	    259
+	__kmpc_proxy_task_completed_ooo	    260
+    %endif
+%endif
+
 # User API entry points that have both lower- and upper- case versions for Fortran.
 # Number for lowercase version is indicated.  Number for uppercase is obtained by adding 1000.
 # User API entry points are entry points that start with 'kmp_' or 'omp_'.
--- a/openmp/runtime/src/kmp.h
+++ b/openmp/runtime/src/kmp.h
@ -51,6 +51,8 @@
 #define TASK_UNTIED              0
 #define TASK_EXPLICIT            1
 #define TASK_IMPLICIT            0
+#define TASK_PROXY               1
+#define TASK_FULL                0

 #define KMP_CANCEL_THREADS
 #define KMP_THREAD_ATTR
@ -1987,7 +1989,12 @@ typedef struct kmp_tasking_flags {          /* Total struct must be exactly 32 b
    unsigned merged_if0  : 1;               /* no __kmpc_task_{begin/complete}_if0 calls in if0 code path */
 #if OMP_40_ENABLED
    unsigned destructors_thunk : 1;         /* set if the compiler creates a thunk to invoke destructors from the runtime */
+#if OMP_41_ENABLED
+    unsigned proxy       : 1;               /* task is a proxy task (it will be executed outside the context of the RTL) */
+    unsigned reserved    : 11;              /* reserved for compiler use */
+#else
    unsigned reserved    : 12;              /* reserved for compiler use */
+#endif
 #else // OMP_40_ENABLED
    unsigned reserved    : 13;              /* reserved for compiler use */
 #endif // OMP_40_ENABLED
@ -2077,6 +2084,9 @@ typedef struct kmp_base_task_team {
                                                   /* TRUE means tt_threads_data is set up and initialized */
    kmp_int32               tt_nproc;              /* #threads in team           */
    kmp_int32               tt_max_threads;        /* number of entries allocated for threads_data array */
+#if OMP_41_ENABLED
+    kmp_int32               tt_found_proxy_tasks;  /* Have we found proxy tasks since last barrier */
+#endif

    KMP_ALIGN_CACHE
    volatile kmp_uint32     tt_unfinished_threads; /* #threads still active      */
@ -3147,7 +3157,7 @@ int __kmp_execute_tasks_oncore(kmp_info_t *thread, kmp_int32 gtid, kmp_flag_onco
 extern void __kmp_reap_task_teams( void );
 extern void __kmp_unref_task_team( kmp_task_team_t *task_team, kmp_info_t *thread );
 extern void __kmp_wait_to_unref_task_teams( void );
-extern void __kmp_task_team_setup ( kmp_info_t *this_thr, kmp_team_t *team, int both );
+extern void __kmp_task_team_setup ( kmp_info_t *this_thr, kmp_team_t *team, int both, int always );
 extern void __kmp_task_team_sync  ( kmp_info_t *this_thr, kmp_team_t *team );
 extern void __kmp_task_team_wait  ( kmp_info_t *this_thr, kmp_team_t *team
 #if USE_ITT_BUILD
@ -3302,8 +3312,16 @@ KMP_EXPORT kmp_int32 __kmpc_cancellationpoint(ident_t* loc_ref, kmp_int32 gtid,
 KMP_EXPORT kmp_int32 __kmpc_cancel_barrier(ident_t* loc_ref, kmp_int32 gtid);
 KMP_EXPORT int __kmp_get_cancellation_status(int cancel_kind);

+#if OMP_41_ENABLED
+
+KMP_EXPORT void __kmpc_proxy_task_completed( kmp_int32 gtid, kmp_task_t *ptask );
+KMP_EXPORT void __kmpc_proxy_task_completed_ooo ( kmp_task_t *ptask );
+
 #endif

+#endif
+
+
 /*
 * Lock interface routines (fast versions with gtid passed in)
 */
--- a/openmp/runtime/src/kmp_barrier.cpp
+++ b/openmp/runtime/src/kmp_barrier.cpp
@ -1135,7 +1135,7 @@ __kmp_barrier(enum barrier_type bt, int gtid, int is_split, size_t reduce_size,
            if (__kmp_tasking_mode != tskm_immediate_exec) {
                __kmp_task_team_wait(this_thr, team
                                     USE_ITT_BUILD_ARG(itt_sync_obj) );
-                __kmp_task_team_setup(this_thr, team, 0); // use 0 to only setup the current team
+                __kmp_task_team_setup(this_thr, team, 0, 0); // use 0,0 to only setup the current team if nthreads > 1
            }


@ -1227,9 +1227,32 @@ __kmp_barrier(enum barrier_type bt, int gtid, int is_split, size_t reduce_size,
    } else { // Team is serialized.
        status = 0;
        if (__kmp_tasking_mode != tskm_immediate_exec) {
+#if OMP_41_ENABLED
+            if ( this_thr->th.th_task_team != NULL ) {
+                void *itt_sync_obj = NULL;
+#if USE_ITT_NOTIFY
+                if (__itt_sync_create_ptr || KMP_ITT_DEBUG) {
+                    itt_sync_obj = __kmp_itt_barrier_object(gtid, bt, 1);
+                    __kmp_itt_barrier_starting(gtid, itt_sync_obj);
+                }
+#endif
+
+                kmp_task_team_t * task_team = this_thr->th.th_task_team;
+                KMP_DEBUG_ASSERT(task_team->tt.tt_found_proxy_tasks == TRUE);
+                __kmp_task_team_wait(this_thr, team
+                                               USE_ITT_BUILD_ARG(itt_sync_obj));
+                __kmp_task_team_setup(this_thr, team, 0, 0);
+
+#if USE_ITT_BUILD
+                if (__itt_sync_create_ptr || KMP_ITT_DEBUG)
+                    __kmp_itt_barrier_finished(gtid, itt_sync_obj);
+#endif /* USE_ITT_BUILD */
+            }
+#else
            // The task team should be NULL for serialized code (tasks will be executed immediately)
            KMP_DEBUG_ASSERT(team->t.t_task_team[this_thr->th.th_task_state] == NULL);
            KMP_DEBUG_ASSERT(this_thr->th.th_task_team == NULL);
+#endif
        }
    }
    KA_TRACE(15, ("__kmp_barrier: T#%d(%d:%d) is leaving with return value %d\n",
@ -1532,7 +1555,7 @@ __kmp_fork_barrier(int gtid, int tid)
 #endif

        if (__kmp_tasking_mode != tskm_immediate_exec) {
-            __kmp_task_team_setup(this_thr, team, 1);  // 1 indicates setup both task teams
+            __kmp_task_team_setup(this_thr, team, 1, 0);  // 1,0 indicates setup both task teams if nthreads > 1
        }

        /* The master thread may have changed its blocktime between the join barrier and the
--- a/openmp/runtime/src/kmp_csupport.c
+++ b/openmp/runtime/src/kmp_csupport.c
@ -461,6 +461,14 @@ __kmpc_end_serialized_parallel(ident_t *loc, kmp_int32 global_tid)
    this_thr    = __kmp_threads[ global_tid ];
    serial_team = this_thr->th.th_serial_team;

+   #if OMP_41_ENABLED
+   kmp_task_team_t *   task_team = this_thr->th.th_task_team;
+
+   // we need to wait for the proxy tasks before finishing the thread
+   if ( task_team != NULL && task_team->tt.tt_found_proxy_tasks )
+        __kmp_task_team_wait(this_thr, serial_team, NULL ); // is an ITT object needed here?
+   #endif
+
    KMP_MB();
    KMP_DEBUG_ASSERT( serial_team );
    KMP_ASSERT(       serial_team -> t.t_serialized );
--- a/openmp/runtime/src/kmp_runtime.c
+++ b/openmp/runtime/src/kmp_runtime.c
@ -3940,6 +3940,16 @@ __kmp_unregister_root_current_thread( int gtid )

    KMP_MB();

+#if OMP_41_ENABLED
+   kmp_info_t * thread = __kmp_threads[gtid];
+   kmp_team_t * team = thread->th.th_team;
+   kmp_task_team_t *   task_team = thread->th.th_task_team;
+
+   // we need to wait for the proxy tasks before finishing the thread
+   if ( task_team != NULL && task_team->tt.tt_found_proxy_tasks )
+        __kmp_task_team_wait(thread, team, NULL );
+#endif
+
    __kmp_reset_root(gtid, root);

    /* free up this thread slot */
--- a/openmp/runtime/src/kmp_taskdeps.cpp
+++ b/openmp/runtime/src/kmp_taskdeps.cpp
@ -403,6 +403,9 @@ __kmpc_omp_task_with_deps( ident_t *loc_ref, kmp_int32 gtid, kmp_task_t * new_ta
    kmp_taskdata_t * current_task = thread->th.th_current_task;

    bool serial = current_task->td_flags.team_serial || current_task->td_flags.tasking_ser || current_task->td_flags.final;
+#if OMP_41_ENABLED
+    serial = serial && !(new_taskdata->td_flags.proxy == TASK_PROXY);
+#endif

    if ( !serial && ( ndeps > 0 || ndeps_noalias > 0 )) {
        /* if no dependencies have been tracked yet, create the dependence hash */
@ -425,11 +428,20 @@ __kmpc_omp_task_with_deps( ident_t *loc_ref, kmp_int32 gtid, kmp_task_t * new_ta
                  new_taskdata ) );
            return TASK_CURRENT_NOT_QUEUED;
        }
+    } else {
+#if OMP_41_ENABLED
+        kmp_task_team_t * task_team = thread->th.th_task_team;
+        if ( task_team && task_team->tt.tt_found_proxy_tasks )
+           __kmpc_omp_wait_deps ( loc_ref, gtid, ndeps, dep_list, ndeps_noalias, noalias_dep_list );
+        else
+#endif
+           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 __kmpc_omp_task\n", gtid, loc_ref,
-                  new_taskdata ) );    
+                  new_taskdata ) );

    return __kmpc_omp_task(loc_ref,gtid,new_task);
 }
@ -460,9 +472,15 @@ __kmpc_omp_wait_deps ( ident_t *loc_ref, kmp_int32 gtid, kmp_int32 ndeps, kmp_de
    kmp_taskdata_t * current_task = thread->th.th_current_task;

    // We can return immediately as:
-    //   - dependences are not computed in serial teams
+    //   - dependences are not computed in serial teams (except if we have proxy tasks)
    //   - if the dephash is not yet created it means we have nothing to wait for
-    if ( current_task->td_flags.team_serial || current_task->td_flags.tasking_ser || current_task->td_flags.final || current_task->td_dephash == NULL ) {
+    bool ignore = current_task->td_flags.team_serial || current_task->td_flags.tasking_ser || current_task->td_flags.final;
+#if OMP_41_ENABLED
+    ignore = ignore && 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;
    }
--- a/openmp/runtime/src/kmp_tasking.c
+++ b/openmp/runtime/src/kmp_tasking.c
@ -32,6 +32,10 @@ static void __kmp_enable_tasking( kmp_task_team_t *task_team, kmp_info_t *this_t
 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 );

+#ifdef OMP_41_ENABLED
+static void __kmp_bottom_half_finish_proxy( kmp_int32 gtid, kmp_task_t * ptask );
+#endif
+
 static inline void __kmp_null_resume_wrapper(int gtid, volatile void *flag) {
    switch (((kmp_flag_64 *)flag)->get_type()) {
    case flag32: __kmp_resume_32(gtid, NULL); break;
@ -312,8 +316,19 @@ __kmp_push_task(kmp_int32 gtid, kmp_task_t * task )
    // Lock the deque for the task push operation
    __kmp_acquire_bootstrap_lock( & thread_data -> td.td_deque_lock );

+#if OMP_41_ENABLED
+    // Need to recheck as we can get a proxy task from a thread outside of OpenMP
+    if ( TCR_4(thread_data -> td.td_deque_ntasks) >= TASK_DEQUE_SIZE )
+    {
+        __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
    // 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 );
+#endif

    thread_data -> td.td_deque[ thread_data -> td.td_deque_tail ] = taskdata;  // Push taskdata
    // Wrap index.
@ -780,6 +795,10 @@ __kmp_init_implicit_task( ident_t *loc_ref, kmp_info_t *this_thr, kmp_team_t *te

    task->td_flags.tiedness    = TASK_TIED;
    task->td_flags.tasktype    = TASK_IMPLICIT;
+#if OMP_41_ENABLED
+    task->td_flags.proxy       = TASK_FULL;
+#endif
+
    // All implicit tasks are executed immediately, not deferred
    task->td_flags.task_serial = 1;
    task->td_flags.tasking_ser = ( __kmp_tasking_mode == tskm_immediate_exec );
@ -864,6 +883,40 @@ __kmp_task_alloc( ident_t *loc_ref, kmp_int32 gtid, kmp_tasking_flags_t *flags,
        flags->final = 1;
    }

+#if OMP_41_ENABLED
+    if ( flags->proxy == TASK_PROXY ) {
+        flags->tiedness = TASK_UNTIED;
+        flags->merged_if0 = 1;
+
+        /* are we running in a sequential parallel or tskm_immediate_exec... we need tasking support enabled */
+        if ( (thread->th.th_task_team) == NULL ) {
+            /* This should only happen if the team is serialized
+                setup a task team and propagate it to the thread
+            */
+            KMP_DEBUG_ASSERT(team->t.t_serialized);
+            KA_TRACE(30,("T#%d creating task team in __kmp_task_alloc for proxy task\n", gtid));
+            __kmp_task_team_setup(thread,team,0,1); // 0,1 indicates only setup the current team regardless of nthreads
+            thread->th.th_task_team = team->t.t_task_team[thread->th.th_task_state];
+        }
+        kmp_task_team_t * task_team = thread->th.th_task_team;
+
+        /* tasking must be enabled now as the task might not be pushed */
+        if ( !KMP_TASKING_ENABLED( task_team ) ) {
+            KA_TRACE(30,("T#%d enabling tasking in __kmp_task_alloc for proxy task\n", gtid));
+            __kmp_enable_tasking( task_team, thread );
+            kmp_int32 tid = thread->th.th_info.ds.ds_tid;
+            kmp_thread_data_t * 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 );
+            }
+        }
+
+        if ( task_team->tt.tt_found_proxy_tasks == FALSE )
+          TCW_4(task_team -> tt.tt_found_proxy_tasks, TRUE);
+    }
+#endif
+
    // Calculate shared structure offset including padding after kmp_task_t struct
    // to align pointers in shared struct
    shareds_offset = sizeof( kmp_taskdata_t ) + sizeof_kmp_task_t;
@ -913,7 +966,11 @@ __kmp_task_alloc( ident_t *loc_ref, kmp_int32 gtid, kmp_tasking_flags_t *flags,
    taskdata->td_taskwait_counter = 0;
    taskdata->td_taskwait_thread  = 0;
    KMP_DEBUG_ASSERT( taskdata->td_parent != NULL );
-    copy_icvs( &taskdata->td_icvs, &taskdata->td_parent->td_icvs );
+#if OMP_41_ENABLED
+    // avoid copying icvs for proxy tasks
+    if ( flags->proxy == TASK_FULL )
+#endif
+       copy_icvs( &taskdata->td_icvs, &taskdata->td_parent->td_icvs );

    taskdata->td_flags.tiedness    = flags->tiedness;
    taskdata->td_flags.final       = flags->final;
@ -921,6 +978,9 @@ __kmp_task_alloc( ident_t *loc_ref, kmp_int32 gtid, kmp_tasking_flags_t *flags,
 #if OMP_40_ENABLED
    taskdata->td_flags.destructors_thunk = flags->destructors_thunk;
 #endif // OMP_40_ENABLED
+#if OMP_41_ENABLED
+    taskdata->td_flags.proxy           = flags->proxy;
+#endif
    taskdata->td_flags.tasktype    = TASK_EXPLICIT;

    // GEH - TODO: fix this to copy parent task's value of tasking_ser flag
@ -949,8 +1009,14 @@ __kmp_task_alloc( ident_t *loc_ref, kmp_int32 gtid, kmp_tasking_flags_t *flags,
    taskdata->td_dephash = NULL;
    taskdata->td_depnode = NULL;
 #endif
-    // Only need to keep track of child task counts if team parallel and tasking not serialized
-    if ( !( taskdata -> td_flags.team_serial || taskdata -> td_flags.tasking_ser ) ) {
+
+    // Only need to keep track of child task counts if team parallel and tasking not serialized or if it is a proxy task
+#if OMP_41_ENABLED
+    if ( flags->proxy == TASK_PROXY || !( taskdata -> td_flags.team_serial || taskdata -> td_flags.tasking_ser ) ) 
+#else
+    if ( !( taskdata -> td_flags.team_serial || taskdata -> td_flags.tasking_ser ) ) 
+#endif
+    {
        KMP_TEST_THEN_INC32( (kmp_int32 *)(& parent_task->td_incomplete_child_tasks) );
 #if OMP_40_ENABLED
        if ( parent_task->td_taskgroup )
@ -989,9 +1055,14 @@ __kmpc_omp_task_alloc( ident_t *loc_ref, kmp_int32 gtid, kmp_int32 flags,
    input_flags->native = FALSE;
    // __kmp_task_alloc() sets up all other runtime flags

-    KA_TRACE(10, ("__kmpc_omp_task_alloc(enter): T#%d loc=%p, flags=(%s) "
+    KA_TRACE(10, ("__kmpc_omp_task_alloc(enter): T#%d loc=%p, flags=(%s %s) "
                  "sizeof_task=%ld sizeof_shared=%ld entry=%p\n",
                  gtid, loc_ref, input_flags->tiedness ? "tied  " : "untied",
+#if OMP_41_ENABLED
+                  input_flags->proxy ? "proxy" : "",
+#else
+		  "",
+#endif
                  sizeof_kmp_task_t, sizeof_shareds, task_entry) );

    retval = __kmp_task_alloc( loc_ref, gtid, input_flags, sizeof_kmp_task_t,
@ -1019,6 +1090,27 @@ __kmp_invoke_task( kmp_int32 gtid, kmp_task_t *task, kmp_taskdata_t * current_ta
    KA_TRACE(30, ("__kmp_invoke_task(enter): T#%d invoking task %p, current_task=%p\n",
                  gtid, taskdata, current_task) );

+#if OMP_41_ENABLED
+    if ( taskdata->td_flags.proxy == TASK_PROXY &&
+         taskdata->td_flags.complete == 1)
+         {
+            // This is a proxy task that was already completed but it needs to run
+            // its bottom-half finish
+            KA_TRACE(30, ("__kmp_invoke_task: T#%d running bottom finish for proxy task %p\n",
+                  gtid, taskdata) );
+
+            __kmp_bottom_half_finish_proxy(gtid,task);
+
+            KA_TRACE(30, ("__kmp_invoke_task(exit): T#%d completed bottom finish for proxy task %p, resuming task %p\n", gtid, taskdata, current_task) );
+
+            return;
+         }
+#endif
+
+#if OMP_41_ENABLED
+    // Proxy tasks are not handled by the runtime
+    if ( taskdata->td_flags.proxy != TASK_PROXY )
+#endif
    __kmp_task_start( gtid, task, current_task );

 #if OMPT_SUPPORT
@ -1075,9 +1167,13 @@ __kmp_invoke_task( kmp_int32 gtid, kmp_task_t *task, kmp_taskdata_t * current_ta
    }
 #endif

-    __kmp_task_finish( gtid, task, current_task );
+#if OMP_41_ENABLED
+    // Proxy tasks are not handled by the runtime
+    if ( taskdata->td_flags.proxy != TASK_PROXY )
+#endif
+       __kmp_task_finish( gtid, task, current_task );

-    KA_TRACE(30, ("__kmp_inovke_task(exit): T#%d completed task %p, resuming task %p\n",
+    KA_TRACE(30, ("__kmp_invoke_task(exit): T#%d completed task %p, resuming task %p\n",
                  gtid, taskdata, current_task) );
    return;
 }
@ -1140,8 +1236,11 @@ __kmp_omp_task( kmp_int32 gtid, kmp_task_t * new_task, bool serialize_immediate

    /* Should we execute the new task or queue it?   For now, let's just always try to
       queue it.  If the queue fills up, then we'll execute it.  */
-
+#if OMP_41_ENABLED
+    if ( new_taskdata->td_flags.proxy == TASK_PROXY || __kmp_push_task( gtid, new_task ) == TASK_NOT_PUSHED ) // if cannot defer
+#else
    if ( __kmp_push_task( gtid, new_task ) == TASK_NOT_PUSHED ) // if cannot defer
+#endif
    {                                                           // Execute this task immediately
        kmp_taskdata_t * current_task = __kmp_threads[ gtid ] -> th.th_current_task;
        if ( serialize_immediate )
@ -1216,7 +1315,12 @@ __kmpc_omp_taskwait( ident_t *loc_ref, kmp_int32 gtid )
            __kmp_itt_taskwait_starting( gtid, itt_sync_obj );
 #endif /* USE_ITT_BUILD */

-        if ( ! taskdata->td_flags.team_serial ) {
+#if OMP_41_ENABLED
+        if ( ! taskdata->td_flags.team_serial || (thread->th.th_task_team != NULL && thread->th.th_task_team->tt.tt_found_proxy_tasks) ) 
+#else
+        if ( ! taskdata->td_flags.team_serial ) 
+#endif
+	{
            // GEH: if team serialized, avoid reading the volatile variable below.
            kmp_flag_32 flag(&(taskdata->td_incomplete_child_tasks), 0U);
            while ( TCR_4(taskdata -> td_incomplete_child_tasks) != 0 ) {
@ -1338,7 +1442,12 @@ __kmpc_end_taskgroup( ident_t* loc, int gtid )
            __kmp_itt_taskwait_starting( gtid, itt_sync_obj );
 #endif /* USE_ITT_BUILD */

-        if ( ! taskdata->td_flags.team_serial ) {
+#if OMP_41_ENABLED
+        if ( ! taskdata->td_flags.team_serial || (thread->th.th_task_team != NULL && thread->th.th_task_team->tt.tt_found_proxy_tasks) ) 
+#else
+        if ( ! taskdata->td_flags.team_serial ) 
+#endif
+	{
            kmp_flag_32 flag(&(taskgroup->count), 0U);
            while ( TCR_4(taskgroup->count) != 0 ) {
                flag.execute_tasks(thread, gtid, FALSE, &thread_finished
@ -1582,7 +1691,11 @@ static inline int __kmp_execute_tasks_template(kmp_info_t *thread, kmp_int32 gti

    nthreads = task_team -> tt.tt_nproc;
    unfinished_threads = &(task_team -> tt.tt_unfinished_threads);
+#if OMP_41_ENABLED
+    KMP_DEBUG_ASSERT( nthreads > 1 || task_team->tt.tt_found_proxy_tasks);
+#else
    KMP_DEBUG_ASSERT( nthreads > 1 );
+#endif
    KMP_DEBUG_ASSERT( TCR_4((int)*unfinished_threads) >= 0 );

    // Choose tasks from our own work queue.
@ -1617,7 +1730,13 @@ static inline int __kmp_execute_tasks_template(kmp_info_t *thread, kmp_int32 gti

    // This thread's work queue is empty.  If we are in the final spin loop
    // of the barrier, check and see if the termination condition is satisfied.
-    if (final_spin) {
+#if OMP_41_ENABLED
+    // The work queue may be empty but there might be proxy tasks still executing
+    if (final_spin && TCR_4(current_task -> td_incomplete_child_tasks) == 0) 
+#else
+    if (final_spin) 
+#endif
+    {
        // First, decrement the #unfinished threads, if that has not already
        // been done.  This decrement might be to the spin location, and
        // result in the termination condition being satisfied.
@ -1639,6 +1758,12 @@ static inline int __kmp_execute_tasks_template(kmp_info_t *thread, kmp_int32 gti
        }
    }

+#if OMP_41_ENABLED
+    // check if there are other threads to steal from, otherwise go back
+    if ( nthreads  == 1 )
+        goto start;
+#endif
+
    // Try to steal from the last place I stole from successfully.
    tid = thread -> th.th_info.ds.ds_tid;//__kmp_tid_from_gtid( gtid );
    last_stolen = threads_data[ tid ].td.td_deque_last_stolen;
@ -1686,7 +1811,13 @@ static inline int __kmp_execute_tasks_template(kmp_info_t *thread, kmp_int32 gti

        // The victims's work queue is empty.  If we are in the final spin loop
        // of the barrier, check and see if the termination condition is satisfied.
-        if (final_spin) {
+#if OMP_41_ENABLED
+        // The work queue may be empty but there might be proxy tasks still executing
+        if (final_spin && TCR_4(current_task -> td_incomplete_child_tasks) == 0) 
+#else
+        if (final_spin) 
+#endif
+	{
            // First, decrement the #unfinished threads, if that has not already
            // been done.  This decrement might be to the spin location, and
            // result in the termination condition being satisfied.
@ -1793,7 +1924,13 @@ static inline int __kmp_execute_tasks_template(kmp_info_t *thread, kmp_int32 gti
        // Going on and finding a new victim to steal from is expensive, as it
        // involves a lot of cache misses, so we definitely want to re-check the
        // termination condition before doing that.
-        if (final_spin) {
+#if OMP_41_ENABLED
+        // The work queue may be empty but there might be proxy tasks still executing
+        if (final_spin && TCR_4(current_task -> td_incomplete_child_tasks) == 0) 
+#else
+        if (final_spin) 
+#endif
+	{
            // First, decrement the #unfinished threads, if that has not already
            // been done.  This decrement might be to the spin location, and
            // result in the termination condition being satisfied.
@ -2073,8 +2210,8 @@ __kmp_realloc_task_threads_data( kmp_info_t *thread, kmp_task_team_t *task_team
                            __kmp_allocate( nthreads * sizeof(kmp_thread_data_t) );
                // copy old data to new data
                KMP_MEMCPY_S( (void *) new_data, nthreads * sizeof(kmp_thread_data_t),
-                            (void *) old_data,
-                            maxthreads * sizeof(kmp_taskdata_t *) );
+			(void *) old_data, 
+                        maxthreads * sizeof(kmp_taskdata_t *) );

 #ifdef BUILD_TIED_TASK_STACK
                // GEH: Figure out if this is the right thing to do
@ -2194,6 +2331,9 @@ __kmp_allocate_task_team( kmp_info_t *thread, kmp_team_t *team )
    }

    TCW_4(task_team -> tt.tt_found_tasks, FALSE);
+#if OMP_41_ENABLED
+    TCW_4(task_team -> tt.tt_found_proxy_tasks, FALSE);
+#endif
    task_team -> tt.tt_nproc = nthreads = team->t.t_nproc;

    TCW_4( task_team -> tt.tt_unfinished_threads, nthreads );
@ -2365,11 +2505,11 @@ __kmp_wait_to_unref_task_teams(void)
 // an already created, unused one if it already exists.
 // This may be called by any thread, but only for teams with # threads >1.
 void
-__kmp_task_team_setup( kmp_info_t *this_thr, kmp_team_t *team, int both )
+__kmp_task_team_setup( kmp_info_t *this_thr, kmp_team_t *team, int both, int always )
 {
    KMP_DEBUG_ASSERT( __kmp_tasking_mode != tskm_immediate_exec );

-    if ( ( team->t.t_task_team[this_thr->th.th_task_state] == NULL ) && ( team->t.t_nproc > 1 ) ) {
+    if ( ( team->t.t_task_team[this_thr->th.th_task_state] == NULL ) && ( always || team->t.t_nproc > 1 ) ) {
        // Allocate a new task team, which will be propagated to
        // all of the worker threads after the barrier.  As they
        // spin in the barrier release phase, then will continue
@ -2431,7 +2571,7 @@ __kmp_task_team_sync( kmp_info_t *this_thr, kmp_team_t *team )

 //------------------------------------------------------------------------------
 // __kmp_task_team_wait: Master thread waits for outstanding tasks after the
-// barrier gather phase.  Only called by master thread if #threads in team > 1 !
+// barrier gather phase.  Only called by master thread if #threads in team > 1 or if proxy tasks were created
 void
 __kmp_task_team_wait( kmp_info_t *this_thr, kmp_team_t *team
                      USE_ITT_BUILD_ARG(void * itt_sync_obj)
@ -2457,7 +2597,12 @@ __kmp_task_team_wait( kmp_info_t *this_thr, kmp_team_t *team
        // The master thread is not included in the ref count.
        KA_TRACE( 20, ( "__kmp_task_team_wait: Master T#%d deactivating task_team %p\n",
                          __kmp_gtid_from_thread( this_thr ), task_team ) );
+#if OMP_41_ENABLED
+        KMP_DEBUG_ASSERT( task_team->tt.tt_nproc > 1 || task_team->tt.tt_found_proxy_tasks == TRUE );
+        TCW_SYNC_4( task_team->tt.tt_found_proxy_tasks, FALSE );
+#else
        KMP_DEBUG_ASSERT( task_team->tt.tt_nproc > 1 );
+#endif
        TCW_SYNC_4( task_team->tt.tt_active, FALSE );
        KMP_MB();

@ -2505,3 +2650,176 @@ __kmp_tasking_barrier( kmp_team_t *team, kmp_info_t *thread, int gtid )
 #endif /* USE_ITT_BUILD */
 }

+
+#if OMP_41_ENABLED
+
+/* __kmp_give_task puts a task into a given thread queue if:
+    - the queue for that thread it was created
+    - there's space in that queue
+
+    Because of this, __kmp_push_task needs to check if there's space after getting the lock
+ */
+static bool __kmp_give_task ( kmp_info_t *thread, kmp_int32 tid, kmp_task_t * task )
+{
+    kmp_task_team_t *   task_team = thread->th.th_task_team;
+    kmp_thread_data_t * thread_data = & task_team -> tt.tt_threads_data[ tid ];
+    kmp_taskdata_t *    taskdata = KMP_TASK_TO_TASKDATA(task);
+    bool result = false;
+
+    KA_TRACE(20, ("__kmp_give_task: trying to give task %p to thread %d.\n", taskdata, tid ) );
+
+    // assert tasking is enabled? what if not?
+    KMP_DEBUG_ASSERT( task_team != NULL );
+
+    if (thread_data -> td.td_deque == NULL ) {
+        // There's no queue in this thread, go find another one
+        // We're guaranteed that at least one thread has a queue
+        KA_TRACE(30, ("__kmp_give_task: thread %d has no queue while giving task %p.\n", tid, taskdata ) );
+        return result;
+    }
+
+    if ( TCR_4(thread_data -> td.td_deque_ntasks) >= TASK_DEQUE_SIZE )
+    {
+        KA_TRACE(30, ("__kmp_give_task: queue is full while giving task %p to thread %d.\n", taskdata, tid ) );
+        return result;
+    }
+
+    __kmp_acquire_bootstrap_lock( & thread_data-> td.td_deque_lock );
+
+    if ( TCR_4(thread_data -> td.td_deque_ntasks) >= TASK_DEQUE_SIZE )
+    {
+        KA_TRACE(30, ("__kmp_give_task: queue is full while giving task %p to thread %d.\n", taskdata, tid ) );
+        goto release_and_exit;
+    }
+
+    thread_data -> td.td_deque[ thread_data -> td.td_deque_tail ] = taskdata;
+    // Wrap index.
+    thread_data -> td.td_deque_tail = ( thread_data -> td.td_deque_tail + 1 ) & TASK_DEQUE_MASK;
+    TCW_4(thread_data -> td.td_deque_ntasks, TCR_4(thread_data -> td.td_deque_ntasks) + 1);
+
+    result = true;
+    KA_TRACE(30, ("__kmp_give_task: succesfully gave task %p to thread %d.\n", taskdata, tid ) );
+
+release_and_exit:
+    __kmp_release_bootstrap_lock( & thread_data-> td.td_deque_lock );
+
+     return result;
+}
+
+
+/* The finish of the a proxy tasks is divided in two pieces:
+    - the top half is the one that can be done from a thread outside the team
+    - the bottom half must be run from a them within the team
+
+    In order to run the bottom half the task gets queued back into one of the threads of the team.
+    Once the td_incomplete_child_task counter of the parent is decremented the threads can leave the barriers.
+    So, the bottom half needs to be queued before the counter is decremented. The top half is therefore divided in two parts:
+    - things that can be run before queuing the bottom half
+    - things that must be run after queuing the bottom half
+
+    This creates a second race as the bottom half can free the task before the second top half is executed. To avoid this
+    we use the td_incomplete_child_task of the proxy task to synchronize the top and bottom half.
+*/
+
+static void __kmp_first_top_half_finish_proxy( kmp_taskdata_t * taskdata )
+{
+    KMP_DEBUG_ASSERT( taskdata -> td_flags.tasktype == TASK_EXPLICIT );
+    KMP_DEBUG_ASSERT( taskdata -> td_flags.proxy == TASK_PROXY );
+    KMP_DEBUG_ASSERT( taskdata -> td_flags.complete == 0 );
+    KMP_DEBUG_ASSERT( taskdata -> td_flags.freed == 0 );
+
+    taskdata -> td_flags.complete = 1;   // mark the task as completed
+
+    if ( taskdata->td_taskgroup )
+       KMP_TEST_THEN_DEC32( (kmp_int32 *)(& taskdata->td_taskgroup->count) );
+
+    // Create an imaginary children for this task so the bottom half cannot release the task before we have completed the second top half
+    TCR_4(taskdata->td_incomplete_child_tasks++);
+}
+
+static void __kmp_second_top_half_finish_proxy( kmp_taskdata_t * taskdata )
+{
+    kmp_int32 children = 0;
+
+    // Predecrement simulated by "- 1" calculation
+    children = KMP_TEST_THEN_DEC32( (kmp_int32 *)(& taskdata -> td_parent -> td_incomplete_child_tasks) ) - 1;
+    KMP_DEBUG_ASSERT( children >= 0 );
+
+    // Remove the imaginary children
+    TCR_4(taskdata->td_incomplete_child_tasks--);
+}
+
+static void __kmp_bottom_half_finish_proxy( kmp_int32 gtid, kmp_task_t * ptask )
+{
+    kmp_taskdata_t * taskdata = KMP_TASK_TO_TASKDATA(ptask);
+    kmp_info_t * thread = __kmp_threads[ gtid ];
+
+    KMP_DEBUG_ASSERT( taskdata -> td_flags.proxy == TASK_PROXY );
+    KMP_DEBUG_ASSERT( taskdata -> td_flags.complete == 1 ); // top half must run before bottom half
+
+    // We need to wait to make sure the top half is finished
+    // Spinning here should be ok as this should happen quickly
+    while ( TCR_4(taskdata->td_incomplete_child_tasks) > 0 ) ;
+
+    __kmp_release_deps(gtid,taskdata);
+    __kmp_free_task_and_ancestors(gtid, taskdata, thread);
+}
+
+/*!
+@ingroup TASKING
+@param gtid Global Thread ID of encountering thread
+@param ptask Task which execution is completed
+
+Execute the completation of a proxy task from a thread of that is part of the team. Run first and bottom halves directly.
+*/
+void __kmpc_proxy_task_completed( kmp_int32 gtid, kmp_task_t *ptask )
+{
+    KMP_DEBUG_ASSERT( ptask != NULL );
+    kmp_taskdata_t * taskdata = KMP_TASK_TO_TASKDATA(ptask);
+    KA_TRACE(10, ("__kmp_proxy_task_completed(enter): T#%d proxy task %p completing\n", gtid, taskdata ) );
+
+    KMP_DEBUG_ASSERT( taskdata->td_flags.proxy == TASK_PROXY );
+
+    __kmp_first_top_half_finish_proxy(taskdata);
+    __kmp_second_top_half_finish_proxy(taskdata);
+    __kmp_bottom_half_finish_proxy(gtid,ptask);
+
+    KA_TRACE(10, ("__kmp_proxy_task_completed(exit): T#%d proxy task %p completing\n", gtid, taskdata ) );
+}
+
+/*!
+@ingroup TASKING
+@param ptask Task which execution is completed
+
+Execute the completation of a proxy task from a thread that could not belong to the team.
+*/
+void __kmpc_proxy_task_completed_ooo ( kmp_task_t *ptask )
+{
+    KMP_DEBUG_ASSERT( ptask != NULL );
+    kmp_taskdata_t * taskdata = KMP_TASK_TO_TASKDATA(ptask);
+
+    KA_TRACE(10, ("__kmp_proxy_task_completed_ooo(enter): proxy task completing ooo %p\n", taskdata ) );
+
+    KMP_DEBUG_ASSERT( taskdata->td_flags.proxy == TASK_PROXY );
+
+    __kmp_first_top_half_finish_proxy(taskdata);
+
+    // Enqueue task to complete bottom half completation from a thread within the corresponding team
+    kmp_team_t * team = taskdata->td_team;
+    kmp_int32 nthreads = team->t.t_nproc;
+    kmp_info_t *thread;
+    kmp_int32 k = 0;
+
+    do {
+        //This should be similiar to k = __kmp_get_random( thread ) % nthreads but we cannot use __kmp_get_random here
+        //For now we're just linearly trying to find a thread
+        k = (k+1) % nthreads;
+        thread = team->t.t_threads[k];
+    } while ( !__kmp_give_task( thread, k,  ptask ) );
+
+    __kmp_second_top_half_finish_proxy(taskdata);
+
+    KA_TRACE(10, ("__kmp_proxy_task_completed_ooo(exit): proxy task completing ooo %p\n", taskdata ) );
+}
+
+#endif