SWDEV-472840 SWDEV-461980 - Fix null stream sync performance

=> If null stream is not created during sync skip nullstrm creation
=> Do cpu wait on blocking & null stream if it exists

Change-Id: I90d6ced6a2dd1782ba58f3fed4e3608fc0efa55a

Author: Anusha GodavarthySurya

hipamd/src/hip_device.cpp

@@ -257,15 +257,30 @@ void Device::destroyAllStreams() {
 }
 
 // ================================================================================================
-void Device::SyncAllStreams( bool cpu_wait) {
+void Device::SyncAllStreams(bool cpu_wait, bool wait_blocking_streams_only) {
   // Make a local copy to avoid stalls for GPU finish with multiple threads
   std::vector<hip::Stream*> streams;
   streams.reserve(streamSet.size());
   {
     amd::ScopedLock lock(streamSetLock);
-    for (auto it : streamSet) {
-      streams.push_back(it);
-      it->retain();
+    if (wait_blocking_streams_only) {
+      auto null_stream = GetNullStream();
+      for (auto it : streamSet) {
+        if (it != null_stream && (it->Flags() & hipStreamNonBlocking) == 0) {
+          streams.push_back(it);
+          it->retain();
+        }
+      }
+      // Add null stream to the end of the list so that wait happens after all blocking streams.
+      if (null_stream != nullptr) {
+        streams.push_back(null_stream);
+        null_stream->retain();
+      }
+    } else {
+      for (auto it : streamSet) {
+        streams.push_back(it);
+        it->retain();
+      }
     }
   }
   for (auto it : streams) {

hipamd/src/hip_internal.hpp

@@ -595,7 +595,7 @@ class stream_per_thread {
 
     void destroyAllStreams();
 
-    void SyncAllStreams( bool cpu_wait = true);
+    void SyncAllStreams( bool cpu_wait = true, bool wait_blocking_streams_only = false);
 
     bool StreamCaptureBlocking();
 

hipamd/src/hip_stream.cpp

@@ -357,13 +357,23 @@ hipError_t hipStreamSynchronize_common(hipStream_t stream) {
       HIP_RETURN(hipErrorStreamCaptureUnsupported);
     }
   }
-  bool wait = (stream == nullptr || stream == hipStreamLegacy) ? true : false;
-  auto hip_stream = hip::getStream(stream, wait);
 
-  // Wait for the current host queue
-  hip_stream->finish();
-  // Release freed memory for all memory pools on the device
-  hip_stream->GetDevice()->ReleaseFreedMemory();
+  if (stream == nullptr) {
+    // Do cpu wait on null stream and only on blocking streams
+    constexpr bool WaitblockingStreamOnly = true;
+    getCurrentDevice()->SyncAllStreams(true, WaitblockingStreamOnly);
+
+    // Release freed memory for all memory pools on the device
+    getCurrentDevice()->ReleaseFreedMemory();
+  } else {
+    constexpr bool wait = false;
+    auto hip_stream = hip::getStream(stream, wait);
+
+    // Wait for the current host queue
+    hip_stream->finish();
+    // Release freed memory for all memory pools on the device
+    hip_stream->GetDevice()->ReleaseFreedMemory();
+  }
   return hipSuccess;
 }