[Openmp-commits] [openmp] e2069be - [OpenMP] Make isDone lightweight without calling synchronize

[Ye Luo via Openmp-commits]

Author: Ye Luo
Date: 2023-02-17T20:45:43-06:00
New Revision: e2069be83ea88837e1d3bb710aff17cd84ee7b7e

URL: https://github.com/llvm/llvm-project/commit/e2069be83ea88837e1d3bb710aff17cd84ee7b7e
DIFF: https://github.com/llvm/llvm-project/commit/e2069be83ea88837e1d3bb710aff17cd84ee7b7e.diff

LOG: [OpenMP] Make isDone lightweight without calling synchronize

~TaskAsyncInfoWrapperTy() calls isDone. With synchronize inside isDone, we need to handle the error return from synchronize in the destructor.
The consumers of TaskAsyncInfoWrapperTy, targetDataMapper and targetKernel, both call AsyncInfo.synchronize() before exiting.
For this reason in ~TaskAsyncInfoWrapperTy(), calling synchronize() via isDone() is redundant.
This patch removes synchronize() call inside isDone() and makes it a lightweight check.
__tgt_target_nowait_query needs to call synchronize() before checking isDone().

Differential Revision: https://reviews.llvm.org/D144315

Added: 
    

Modified: 
    openmp/libomptarget/include/omptarget.h
    openmp/libomptarget/src/interface.cpp
    openmp/libomptarget/src/omptarget.cpp
    openmp/libomptarget/src/private.h

Removed: 
    


################################################################################
diff  --git a/openmp/libomptarget/include/omptarget.h b/openmp/libomptarget/include/omptarget.h
index dd577e4051e21..4aab729190b9c 100644
--- a/openmp/libomptarget/include/omptarget.h
+++ b/openmp/libomptarget/include/omptarget.h
@@ -17,7 +17,6 @@
 #include <cstdint>
 #include <deque>
 #include <functional>
-#include <optional>
 #include <stddef.h>
 #include <stdint.h>
 #include <type_traits>
@@ -244,12 +243,12 @@ class AsyncInfoTy {
 
   /// Check if all asynchronous operations are completed.
   ///
-  /// \note if the operations are completed, the registered post-processing
-  /// functions will be executed once and unregistered afterwards.
+  /// \note only a lightweight check. If needed, use synchronize() to query the
+  /// status of AsyncInfo before checking.
   ///
   /// \returns true if there is no pending asynchronous operations, false
-  /// otherwise. We return a null value in the case of an error from the plugin.
-  std::optional<bool> isDone();
+  /// otherwise.
+  bool isDone() const;
 
   /// Add a new post-processing function to be executed after synchronization.
   ///

diff  --git a/openmp/libomptarget/src/interface.cpp b/openmp/libomptarget/src/interface.cpp
index 45f499962e4d1..b155d09dcf8c7 100644
--- a/openmp/libomptarget/src/interface.cpp
+++ b/openmp/libomptarget/src/interface.cpp
@@ -412,12 +412,11 @@ EXTERN void __tgt_target_nowait_query(void **AsyncHandle) {
   if (QueryCounter.isAboveThreshold())
     AsyncInfo->SyncType = AsyncInfoTy::SyncTy::BLOCKING;
 
-  auto DoneOrErr = AsyncInfo->isDone();
-  if (!DoneOrErr)
+  if (const int Rc = AsyncInfo->synchronize())
     FATAL_MESSAGE0(1, "Error while querying the async queue for completion.\n");
   // If there are device operations still pending, return immediately without
   // deallocating the handle and increase the current thread query count.
-  if (!*DoneOrErr) {
+  if (!AsyncInfo->isDone()) {
     QueryCounter.increment();
     return;
   }

diff  --git a/openmp/libomptarget/src/omptarget.cpp b/openmp/libomptarget/src/omptarget.cpp
index da91a9ab859fa..441da7c452434 100644
--- a/openmp/libomptarget/src/omptarget.cpp
+++ b/openmp/libomptarget/src/omptarget.cpp
@@ -51,13 +51,7 @@ void *&AsyncInfoTy::getVoidPtrLocation() {
   return BufferLocations.back();
 }
 
-std::optional<bool> AsyncInfoTy::isDone() {
-  if (synchronize() == OFFLOAD_FAIL)
-    return std::nullopt;
-
-  // The async info operations are completed when the internal queue is empty.
-  return isQueueEmpty();
-}
+bool AsyncInfoTy::isDone() const { return isQueueEmpty(); }
 
 int32_t AsyncInfoTy::runPostProcessing() {
   size_t Size = PostProcessingFunctions.size();

diff  --git a/openmp/libomptarget/src/private.h b/openmp/libomptarget/src/private.h
index fe55355e62187..9f156192e1036 100644
--- a/openmp/libomptarget/src/private.h
+++ b/openmp/libomptarget/src/private.h
@@ -250,13 +250,9 @@ class TaskAsyncInfoWrapperTy {
     if (AsyncInfo == &LocalAsyncInfo)
       return;
 
-    auto DoneOrErr = AsyncInfo->isDone();
-    if (!DoneOrErr)
-      FATAL_MESSAGE0(1,
-                     "Error while querying the async queue for completion.\n");
     // If the are device operations still pending, return immediately without
     // deallocating the handle.
-    if (!*DoneOrErr)
+    if (!AsyncInfo->isDone())
       return;
 
     // Delete the handle and unset it from the OpenMP task data.