Merge pull request #1174 from beehive-lab/florin/enable-thread-safe-g…

…etAllDevices

Make {PTX/SPIRV/OCL}BackendImpl::getAllDevices thread-safe

tornado-drivers/opencl/src/main/java/uk/ac/manchester/tornado/drivers/opencl/OCLBackendImpl.java

@@ -62,7 +62,7 @@ public final class OCLBackendImpl implements TornadoAcceleratorBackend {
     private final OCLBackend[][] backends;
     private final List<OCLContextInterface> contexts;
     private OCLBackend[] flatBackends;
-    private List<TornadoDevice> devices;
+    private volatile List<TornadoDevice> devices;
     private final TornadoLogger logger;
 
     public OCLBackendImpl(final OptionValues options, final HotSpotJVMCIRuntime vmRuntime, TornadoVMConfigAccess vmConfig) {
@@ -167,9 +167,13 @@ public TornadoXPUDevice getDevice(int index) {
     @Override
     public List<TornadoDevice> getAllDevices() {
         if (devices == null) {
-            devices = new ArrayList<>();
-            for (int deviceIndex = 0; deviceIndex < getNumDevices(); deviceIndex++) {
-                devices.add(getDevice(deviceIndex));
+            synchronized (this) {
+                if (devices == null) {
+                    devices = new ArrayList<>();
+                    for (int deviceIndex = 0; deviceIndex < getNumDevices(); deviceIndex++) {
+                        devices.add(getDevice(deviceIndex));
+                    }
+                }
             }
         }
         return devices;

tornado-drivers/ptx/src/main/java/uk/ac/manchester/tornado/drivers/ptx/PTXBackendImpl.java

@@ -48,7 +48,7 @@ public final class PTXBackendImpl implements TornadoAcceleratorBackend {
 
     private final PTXBackend[] backends;
     private final TornadoLogger logger;
-    private List<TornadoDevice> devices;
+    private volatile List<TornadoDevice> devices;
 
     public PTXBackendImpl(final OptionValues options, final HotSpotJVMCIRuntime vmRuntime, TornadoVMConfigAccess vmConfig) {
 
@@ -132,9 +132,13 @@ public TornadoXPUDevice getDevice(int index) {
     @Override
     public List<TornadoDevice> getAllDevices() {
         if (devices == null) {
-            devices = new ArrayList<>();
-            for (int i = 0; i < getNumDevices(); i++) {
-                devices.add(backends[i].getDeviceContext().toDevice());
+            synchronized (this) {
+                if (devices == null) {
+                    devices = new ArrayList<>();
+                    for (int i = 0; i < getNumDevices(); i++) {
+                        devices.add(backends[i].getDeviceContext().toDevice());
+                    }
+                }
             }
         }
         return devices;

tornado-drivers/spirv/src/main/java/uk/ac/manchester/tornado/drivers/spirv/SPIRVBackendImpl.java

@@ -67,7 +67,7 @@ public final class SPIRVBackendImpl implements TornadoAcceleratorBackend {
      * devices).
      */
     private int backendCounter;
-    private List<TornadoDevice> devices;
+    private volatile List<TornadoDevice> devices;
 
     public SPIRVBackendImpl(OptionValues options, HotSpotJVMCIRuntime vmRuntime, TornadoVMConfigAccess vmConfigAccess) {
         int numPlatforms = SPIRVRuntimeImpl.getInstance().getNumPlatforms();
@@ -190,9 +190,13 @@ public TornadoXPUDevice getDevice(int index) {
     @Override
     public List<TornadoDevice> getAllDevices() {
         if (devices == null) {
-            devices = new ArrayList<>();
-            for (int i = 0; i < getNumDevices(); i++) {
-                devices.add(flatBackends[i].getDeviceContext().toDevice());
+            synchronized (this) {
+                if (devices == null) {
+                    devices = new ArrayList<>();
+                    for (int i = 0; i < getNumDevices(); i++) {
+                        devices.add(flatBackends[i].getDeviceContext().toDevice());
+                    }
+                }
             }
         }
         return devices;

tornado-unittests/src/main/java/uk/ac/manchester/tornado/unittests/functional/TestStreams.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2024, APT Group, Department of Computer Science,
+ * The University of Manchester.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+package uk.ac.manchester.tornado.unittests.functional;
+
+import org.junit.Test;
+import uk.ac.manchester.tornado.api.ImmutableTaskGraph;
+import uk.ac.manchester.tornado.api.TaskGraph;
+import uk.ac.manchester.tornado.api.TornadoExecutionPlan;
+import uk.ac.manchester.tornado.api.annotations.Parallel;
+import uk.ac.manchester.tornado.api.enums.DataTransferMode;
+import uk.ac.manchester.tornado.api.exceptions.TornadoExecutionPlanException;
+import uk.ac.manchester.tornado.api.types.arrays.DoubleArray;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import static org.junit.Assert.fail;
+
+public class TestStreams {
+
+    private static void deviceDummyCompute(final DoubleArray src, final DoubleArray dst) {
+        for (@Parallel int i = 0; i < src.getSize(); i++) {
+            dst.set(i, src.get(i) * 2);
+        }
+    }
+
+    private static void hostComputeMethod() throws TornadoExecutionPlanException {
+        DoubleArray src = new DoubleArray(1024);
+        DoubleArray dst = new DoubleArray(1024);
+        String threadName = Thread.currentThread().getName();
+
+        TaskGraph taskGraph = new TaskGraph("s1") //
+                .transferToDevice(DataTransferMode.EVERY_EXECUTION, src, dst) //
+                .task(threadName, TestStreams::deviceDummyCompute, src, dst) //
+                .transferToHost(DataTransferMode.EVERY_EXECUTION, dst);
+
+        ImmutableTaskGraph immutableTaskGraph = taskGraph.snapshot();
+        try (TornadoExecutionPlan executor = new TornadoExecutionPlan(immutableTaskGraph)) {
+            executor.execute();
+        }
+    }
+
+    @Test
+    public void testParallelStreams() throws TornadoExecutionPlanException {
+        ArrayList<Integer> s = new ArrayList<>();
+        for(int i = 0; i < 512; i++) {
+            s.add(i);
+        }
+
+        s.parallelStream().forEach(k->{
+            try {
+                hostComputeMethod();
+            } catch (TornadoExecutionPlanException e) {
+                fail(STR."Got exception \{e}");
+            }
+        });
+    }
+
+}