[Openmp-commits] [openmp] r277992 - Do not block on explicit task depending on proxy task
Jonas Hahnfeld via Openmp-commits
openmp-commits at lists.llvm.org
Mon Aug 8 03:08:15 PDT 2016
Author: hahnfeld
Date: Mon Aug 8 05:08:14 2016
New Revision: 277992
URL: http://llvm.org/viewvc/llvm-project?rev=277992&view=rev
Log:
Do not block on explicit task depending on proxy task
Consider the following code:
int dep;
#pragma omp target nowait depend(out: dep)
{
sleep(1);
}
#pragma omp task depend(in: dep)
{
printf("Task with dependency\n");
}
printf("Doing some work...\n");
In its current state the runtime will block on the second task and not
continue execution.
Differential Revision: https://reviews.llvm.org/D23116
Added:
openmp/trunk/runtime/test/tasking/bug_proxy_task_dep_waiting.c
Modified:
openmp/trunk/runtime/src/kmp_taskdeps.cpp
openmp/trunk/runtime/src/kmp_tasking.c
Modified: openmp/trunk/runtime/src/kmp_taskdeps.cpp
URL: http://llvm.org/viewvc/llvm-project/openmp/trunk/runtime/src/kmp_taskdeps.cpp?rev=277992&r1=277991&r2=277992&view=diff
==============================================================================
--- openmp/trunk/runtime/src/kmp_taskdeps.cpp (original)
+++ openmp/trunk/runtime/src/kmp_taskdeps.cpp Mon Aug 8 05:08:14 2016
@@ -482,7 +482,8 @@ __kmpc_omp_task_with_deps( ident_t *loc_
bool serial = current_task->td_flags.team_serial || current_task->td_flags.tasking_ser || current_task->td_flags.final;
#if OMP_45_ENABLED
- serial = serial && !(new_taskdata->td_flags.proxy == TASK_PROXY);
+ 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 )) {
@@ -507,14 +508,8 @@ __kmpc_omp_task_with_deps( ident_t *loc_
return TASK_CURRENT_NOT_QUEUED;
}
} else {
-#if OMP_45_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 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 : "
Modified: openmp/trunk/runtime/src/kmp_tasking.c
URL: http://llvm.org/viewvc/llvm-project/openmp/trunk/runtime/src/kmp_tasking.c?rev=277992&r1=277991&r2=277992&view=diff
==============================================================================
--- openmp/trunk/runtime/src/kmp_tasking.c (original)
+++ openmp/trunk/runtime/src/kmp_tasking.c Mon Aug 8 05:08:14 2016
@@ -622,6 +622,7 @@ __kmp_task_finish( kmp_int32 gtid, kmp_t
{
kmp_taskdata_t * taskdata = KMP_TASK_TO_TASKDATA(task);
kmp_info_t * thread = __kmp_threads[ gtid ];
+ kmp_task_team_t * task_team = thread->th.th_task_team; // might be NULL for serial teams...
kmp_int32 children = 0;
#if OMPT_SUPPORT
@@ -678,6 +679,12 @@ __kmp_task_finish( kmp_int32 gtid, kmp_t
#if OMP_40_ENABLED
if ( taskdata->td_taskgroup )
KMP_TEST_THEN_DEC32( (kmp_int32 *)(& taskdata->td_taskgroup->count) );
+#if OMP_45_ENABLED
+ }
+ // if we found proxy tasks there could exist a dependency chain
+ // with the proxy task as origin
+ if ( !( taskdata -> td_flags.team_serial || taskdata -> td_flags.tasking_ser ) || (task_team && task_team->tt.tt_found_proxy_tasks) ) {
+#endif
__kmp_release_deps(gtid,taskdata);
#endif
}
@@ -715,7 +722,11 @@ __kmp_task_finish( kmp_int32 gtid, kmp_t
if (resumed_task == NULL) {
resumed_task = taskdata->td_parent; // In a serialized task, the resumed task is the parent
}
- else {
+ else
+#if OMP_45_ENABLED
+ if ( !(task_team && task_team->tt.tt_found_proxy_tasks) )
+#endif
+ {
// verify resumed task passed in points to parent
KMP_DEBUG_ASSERT( resumed_task == taskdata->td_parent );
}
Added: openmp/trunk/runtime/test/tasking/bug_proxy_task_dep_waiting.c
URL: http://llvm.org/viewvc/llvm-project/openmp/trunk/runtime/test/tasking/bug_proxy_task_dep_waiting.c?rev=277992&view=auto
==============================================================================
--- openmp/trunk/runtime/test/tasking/bug_proxy_task_dep_waiting.c (added)
+++ openmp/trunk/runtime/test/tasking/bug_proxy_task_dep_waiting.c Mon Aug 8 05:08:14 2016
@@ -0,0 +1,131 @@
+// RUN: %libomp-compile -lpthread && %libomp-run
+#include <stdio.h>
+#include <omp.h>
+#include <pthread.h>
+#include "omp_my_sleep.h"
+
+/*
+ An explicit task can have a dependency on a target task. If it is not
+ directly satisfied, the runtime should not wait but resume execution.
+*/
+
+// Compiler-generated code (emulation)
+typedef long kmp_intptr_t;
+typedef int kmp_int32;
+
+typedef char bool;
+
+typedef struct ident {
+ kmp_int32 reserved_1; /**< might be used in Fortran; see above */
+ kmp_int32 flags; /**< also f.flags; KMP_IDENT_xxx flags; KMP_IDENT_KMPC identifies this union member */
+ kmp_int32 reserved_2; /**< not really used in Fortran any more; see above */
+#if USE_ITT_BUILD
+ /* but currently used for storing region-specific ITT */
+ /* contextual information. */
+#endif /* USE_ITT_BUILD */
+ kmp_int32 reserved_3; /**< source[4] in Fortran, do not use for C++ */
+ char const *psource; /**< String describing the source location.
+ The string is composed of semi-colon separated fields which describe the source file,
+ the function and a pair of line numbers that delimit the construct.
+ */
+} ident_t;
+
+typedef struct kmp_depend_info {
+ kmp_intptr_t base_addr;
+ size_t len;
+ struct {
+ bool in:1;
+ bool out:1;
+ } flags;
+} kmp_depend_info_t;
+
+struct kmp_task;
+typedef kmp_int32 (* kmp_routine_entry_t)( kmp_int32, struct kmp_task * );
+
+typedef struct kmp_task { /* GEH: Shouldn't this be aligned somehow? */
+ void * shareds; /**< pointer to block of pointers to shared vars */
+ kmp_routine_entry_t routine; /**< pointer to routine to call for executing task */
+ kmp_int32 part_id; /**< part id for the task */
+} kmp_task_t;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+kmp_int32 __kmpc_global_thread_num ( ident_t * );
+kmp_task_t*
+__kmpc_omp_task_alloc( ident_t *loc_ref, kmp_int32 gtid, kmp_int32 flags,
+ size_t sizeof_kmp_task_t, size_t sizeof_shareds,
+ kmp_routine_entry_t task_entry );
+void __kmpc_proxy_task_completed_ooo ( kmp_task_t *ptask );
+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_int32
+__kmpc_omp_task( ident_t *loc_ref, kmp_int32 gtid, kmp_task_t * new_task );
+#ifdef __cplusplus
+}
+#endif
+
+void *target(void *task)
+{
+ my_sleep( 0.1 );
+ __kmpc_proxy_task_completed_ooo((kmp_task_t*) task);
+ return NULL;
+}
+
+pthread_t target_thread;
+
+// User's code
+int task_entry(kmp_int32 gtid, kmp_task_t *task)
+{
+ pthread_create(&target_thread, NULL, &target, task);
+ return 0;
+}
+
+int main()
+{
+ int dep;
+
+/*
+ * Corresponds to:
+ #pragma omp target nowait depend(out: dep)
+ {
+ my_sleep( 0.1 );
+ }
+*/
+ kmp_depend_info_t dep_info;
+ dep_info.base_addr = (long) &dep;
+ dep_info.len = sizeof(int);
+ // out = inout per spec and runtime expects this
+ dep_info.flags.in = 1;
+ dep_info.flags.out = 1;
+
+ kmp_int32 gtid = __kmpc_global_thread_num(NULL);
+ kmp_task_t *proxy_task = __kmpc_omp_task_alloc(NULL,gtid,17,sizeof(kmp_task_t),0,&task_entry);
+ __kmpc_omp_task_with_deps(NULL,gtid,proxy_task,1,&dep_info,0,NULL);
+
+ int first_task_finished = 0;
+ #pragma omp task shared(first_task_finished) depend(inout: dep)
+ {
+ first_task_finished = 1;
+ }
+
+ int second_task_finished = 0;
+ #pragma omp task shared(second_task_finished) depend(in: dep)
+ {
+ second_task_finished = 1;
+ }
+
+ // check that execution has been resumed and the runtime has not waited
+ // for the dependencies to be satisfied.
+ int error = (first_task_finished == 1);
+ error += (second_task_finished == 1);
+
+ #pragma omp taskwait
+
+ // by now all tasks should have finished
+ error += (first_task_finished != 1);
+ error += (second_task_finished != 1);
+
+ return error;
+}
More information about the Openmp-commits
mailing list