Implementation of GarbageCollection event

Author: Zhengyu Gu

substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/GCImpl.java

@@ -209,7 +209,7 @@ private boolean collectImpl(GCCause cause, long requestingNanoTime, boolean forc
 
         NoAllocationVerifier nav = noAllocationVerifier.open();
         try {
-            long startTicks = JfrGCEventSupport.startGCPhasePause();
+            long startTicks = JfrGCEventSupport.getTicks();
             try {
                 outOfMemory = doCollectImpl(cause, requestingNanoTime, forceFullGC, false);
                 if (outOfMemory) {
@@ -223,7 +223,7 @@ private boolean collectImpl(GCCause cause, long requestingNanoTime, boolean forc
                     }
                 }
             } finally {
-                JfrGCEventSupport.emitGCPhasePauseEvent(getCollectionEpoch(), cause.getName(), startTicks);
+                JfrGCEventSupport.emitGarbageCollectionEvent(getCollectionEpoch(), cause, startTicks);
             }
         } finally {
             nav.close();

substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/GenScavengeGCName.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2022, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2022, Red Hat Inc. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.svm.core.genscavenge;
+
+import com.oracle.svm.core.heap.GCName;
+import com.oracle.svm.core.SubstrateOptions;
+
+final class GenScavengeGCName extends GCName {
+    public static final GCName GenScavenge;
+
+    static {
+        if (SubstrateOptions.UseEpsilonGC.getValue()) {
+            GenScavenge = new GenScavengeGCName("epsilon");
+        } else {
+            assert SubstrateOptions.UseSerialGC.getValue();
+            GenScavenge = new GenScavengeGCName("serial");
+        }
+    }
+
+    private GenScavengeGCName(String name) {
+        super(name);
+    }
+}

substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/JfrGCEventSupport.java

@@ -30,6 +30,7 @@
 import org.graalvm.word.UnsignedWord;
 
 import com.oracle.svm.core.annotate.Uninterruptible;
+import com.oracle.svm.core.heap.GCCause;
 import com.oracle.svm.core.jfr.JfrBuffer;
 import com.oracle.svm.core.jfr.JfrEvent;
 import com.oracle.svm.core.jfr.JfrNativeEventWriter;
@@ -44,6 +45,13 @@ class JfrGCEventSupport {
     private static final int MAX_PHASE_LEVEL = 4;
     private static int currentPhase;
 
+    public static long getTicks() {
+        if (!HasJfrSupport.get()) {
+            return 0;
+        }
+        return JfrTicks.elapsedTicks();
+    }
+
     public static long startGCPhasePause() {
         if (!HasJfrSupport.get()) {
             return 0;
@@ -52,6 +60,31 @@ public static long startGCPhasePause() {
         return JfrTicks.elapsedTicks();
     }
 
+    @Uninterruptible(reason = "Accesses a JFR buffer.")
+    public static void emitGarbageCollectionEvent(UnsignedWord gcEpoch, GCCause cause, long start) {
+        if (!HasJfrSupport.get()) {
+            return;
+        }
+
+        long end = JfrTicks.elapsedTicks();
+        long pauseTime = end - start;
+        if (SubstrateJVM.isRecording() && SubstrateJVM.get().isEnabled(JfrEvent.GarbageCollection)) {
+            JfrNativeEventWriterData data = StackValue.get(JfrNativeEventWriterData.class);
+            JfrNativeEventWriterDataAccess.initializeThreadLocalNativeBuffer(data);
+
+            JfrNativeEventWriter.beginEventWrite(data, false);
+            JfrNativeEventWriter.putLong(data, JfrEvent.GarbageCollection.getId());
+            JfrNativeEventWriter.putLong(data, start);
+            JfrNativeEventWriter.putLong(data, pauseTime);
+            JfrNativeEventWriter.putLong(data, gcEpoch.rawValue());
+            JfrNativeEventWriter.putLong(data, GenScavengeGCName.GenScavenge.getId());
+            JfrNativeEventWriter.putLong(data, cause.getId());
+            JfrNativeEventWriter.putLong(data, pauseTime);  // sum of pause
+            JfrNativeEventWriter.putLong(data, pauseTime);  // longest pause
+            JfrNativeEventWriter.endEventWrite(data, false);
+        }
+    }
+
     @Uninterruptible(reason = "Accesses a JFR buffer.")
     public static void emitGCPhasePauseEvent(UnsignedWord gcEpoch, String name, long startTicks) {
         if (!HasJfrSupport.get()) {
@@ -62,9 +95,8 @@ public static void emitGCPhasePauseEvent(UnsignedWord gcEpoch, String name, long
         JfrEvent event = getGCPhasePauseEvent(level);
         if (SubstrateJVM.isRecording() && SubstrateJVM.get().isEnabled(event)) {
             long end = JfrTicks.elapsedTicks();
-            JfrBuffer buffer = ((JfrThreadLocal) SubstrateJVM.getThreadLocal()).getNativeBuffer();
             JfrNativeEventWriterData data = StackValue.get(JfrNativeEventWriterData.class);
-            JfrNativeEventWriterDataAccess.initialize(data, buffer);
+            JfrNativeEventWriterDataAccess.initializeThreadLocalNativeBuffer(data);
 
             JfrNativeEventWriter.beginEventWrite(data, false);
             JfrNativeEventWriter.putLong(data, event.getId());

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/heap/GCCause.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -82,6 +82,10 @@ public static GCCause fromId(int causeId) {
         return GCCauses[causeId];
     }
 
+    public static GCCause[] getGCCauses() {
+        return GCCauses;
+    }
+
     @Platforms(Platform.HOSTED_ONLY.class)
     public static void cacheReverseMapping() {
         GCCauses = HostedGCCauseList.toArray(new GCCause[HostedGCCauseList.size()]);

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/heap/GCName.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2022, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2022, Red Hat Inc. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.svm.core.heap;
+
+import java.util.ArrayList;
+import org.graalvm.nativeimage.Platform;
+import org.graalvm.nativeimage.Platforms;
+import org.graalvm.nativeimage.hosted.Feature;
+
+import com.oracle.svm.core.annotate.AutomaticFeature;
+import com.oracle.svm.core.annotate.Uninterruptible;
+import com.oracle.svm.core.annotate.UnknownObjectField;
+/**
+ * This class holds supported garbage collector names.
+ */
+public class GCName {
+    @Platforms(Platform.HOSTED_ONLY.class) private static final ArrayList<GCName> HostedGCNameList = new ArrayList<>();
+
+    @UnknownObjectField(types = {GCName[].class}) protected static GCName[] GCNames;
+
+    private final int id;
+    private final String name;
+
+    @Platforms(Platform.HOSTED_ONLY.class)
+    protected GCName(String name) {
+        this.name = name;
+        this.id = addGCNameMapping();
+    }
+
+    @Platforms(Platform.HOSTED_ONLY.class)
+    private int addGCNameMapping() {
+        synchronized (HostedGCNameList) {
+            int newId = HostedGCNameList.size();
+            HostedGCNameList.add(newId, this);
+            return newId;
+        }
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
+    public int getId() {
+        return id;
+    }
+
+    public static GCName[] getGCNames() {
+        return GCNames;
+    }
+
+    @Platforms(Platform.HOSTED_ONLY.class)
+    public static void cacheReverseMapping() {
+        GCNames = HostedGCNameList.toArray(new GCName[HostedGCNameList.size()]);
+    }
+}
+
+@AutomaticFeature
+class GCNameFeature implements Feature {
+    @Override
+    public void beforeCompilation(BeforeCompilationAccess access) {
+        GCName.cacheReverseMapping();
+        access.registerAsImmutable(GCName.GCNames);
+    }
+}

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jfr/JfrEvent.java

@@ -45,6 +45,7 @@ public enum JfrEvent {
     PhysicalMemory("jdk.PhysicalMemory"),
     ExecutionSample("jdk.ExecutionSample"),
     NativeMethodSample("jdk.NativeMethodSample"),
+    GarbageCollection("jdk.GarbageCollection"),
     GCPhasePauseEvent("jdk.GCPhasePause"),
     GCPhasePauseLevel1Event("jdk.GCPhasePauseLevel1"),
     GCPhasePauseLevel2Event("jdk.GCPhasePauseLevel2"),

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jfr/JfrType.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,9 @@ public enum JfrType {
     Symbol("jdk.types.Symbol"),
     Module("jdk.types.Module"),
     Package("jdk.types.Package"),
-    FrameType("jdk.types.FrameType");
+    FrameType("jdk.types.FrameType"),
+    GCCause("jdk.types.GCCause"),
+    GCName("jdk.types.GCName");
 
     private final long id;
 

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jfr/JfrTypeRepository.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,6 +35,8 @@
 
 import com.oracle.svm.core.SubstrateUtil;
 import com.oracle.svm.core.annotate.Uninterruptible;
+import com.oracle.svm.core.heap.GCCause;
+import com.oracle.svm.core.heap.GCName;
 import com.oracle.svm.core.heap.Heap;
 import com.oracle.svm.core.jfr.traceid.JfrTraceId;
 
@@ -62,6 +64,8 @@ public int write(JfrChunkWriter writer) {
         count += writePackages(writer, typeInfo);
         count += writeModules(writer, typeInfo);
         count += writeClassLoaders(writer, typeInfo);
+        count += writeGCCauses(writer);
+        count += writeGCNames(writer);
         return count;
     }
 
@@ -186,6 +190,42 @@ private static int writeClassLoaders(JfrChunkWriter writer, TypeInfo typeInfo) {
         return NON_EMPTY;
     }
 
+    private static int writeGCCauses(JfrChunkWriter writer) {
+        // GCCauses has null entries
+        GCCause[] causes = GCCause.getGCCauses();
+        int nonNullItems = 0;
+        for (int index = 0; index < causes.length; index++) {
+            if (causes[index] != null) {
+                nonNullItems++;
+            }
+        }
+
+        assert nonNullItems > 0;
+
+        writer.writeCompressedLong(JfrType.GCCause.getId());
+        writer.writeCompressedLong(nonNullItems);
+        for (GCCause cause : causes) {
+            if (cause != null) {
+                writer.writeCompressedLong(cause.getId());
+                writer.writeString(cause.getName());
+            }
+        }
+        return NON_EMPTY;
+    }
+
+    private static int writeGCNames(JfrChunkWriter writer) {
+        GCName[] gcNames = GCName.getGCNames();
+        assert gcNames != null && gcNames.length > 0;
+
+        writer.writeCompressedLong(JfrType.GCName.getId());
+        writer.writeCompressedLong(gcNames.length);
+        for (GCName name : gcNames) {
+            writer.writeCompressedLong(name.getId());
+            writer.writeString(name.getName());
+        }
+        return NON_EMPTY;
+    }
+
     private static void writeClassLoader(JfrChunkWriter writer, ClassLoader cl, long id) {
         JfrSymbolRepository symbolRepo = SubstrateJVM.getSymbolRepository();
         writer.writeCompressedLong(id);