JFR getStackTraceId implementation. JFR Tests. Code cleanup.

Author: jovanstevanovic

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/VMInspectionOptions.java

@@ -87,7 +87,7 @@ public static boolean hasHeapDumpSupport() {
     }
 
     @Fold
-    public static boolean hasJFRSupport() {
+    public static boolean hasJfrSupport() {
         return hasAllOrKeywordMonitoringSupport(MONITORING_JFR_NAME) && !Platform.includedIn(WINDOWS.class);
     }
 

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jdk/AbstractUninterruptibleHashtable.java

@@ -32,8 +32,8 @@
 import org.graalvm.word.UnsignedWord;
 import org.graalvm.word.WordFactory;
 
-import com.oracle.svm.core.UnmanagedMemoryUtil;
 import com.oracle.svm.core.Uninterruptible;
+import com.oracle.svm.core.UnmanagedMemoryUtil;
 
 /**
  * An uninterruptible hashtable with a fixed size that uses chaining in case of a collision.
@@ -76,6 +76,7 @@ protected UninterruptibleEntry copyToHeap(UninterruptibleEntry pointerOnStack, U
 
     @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
     protected void free(UninterruptibleEntry entry) {
+        size--;
         ImageSingletons.lookup(UnmanagedMemorySupport.class).free(entry);
     }
 
@@ -158,7 +159,7 @@ public void clear() {
             }
             table[i] = WordFactory.nullPointer();
         }
-        size = 0;
+        assert size == 0 : "The table is not empty!";
     }
 
     @Override

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

@@ -27,7 +27,6 @@
 import java.nio.charset.StandardCharsets;
 import java.util.concurrent.locks.ReentrantLock;
 
-import com.oracle.svm.core.heap.VMOperationInfos;
 import org.graalvm.compiler.api.replacements.Fold;
 import org.graalvm.compiler.core.common.NumUtil;
 import org.graalvm.nativeimage.IsolateThread;
@@ -38,12 +37,14 @@
 import org.graalvm.word.WordFactory;
 
 import com.oracle.svm.core.Uninterruptible;
+import com.oracle.svm.core.heap.VMOperationInfos;
+import com.oracle.svm.core.jfr.traceid.JfrTraceIdEpoch;
 import com.oracle.svm.core.os.RawFileOperationSupport;
+import com.oracle.svm.core.sampler.SamplerBuffersAccess;
 import com.oracle.svm.core.thread.JavaVMOperation;
 import com.oracle.svm.core.thread.VMOperation;
 import com.oracle.svm.core.thread.VMOperationControl;
 import com.oracle.svm.core.thread.VMThreads;
-import com.oracle.svm.core.jfr.traceid.JfrTraceIdEpoch;
 
 /**
  * This class is used when writing the in-memory JFR data to a file. For all operations, except
@@ -383,6 +384,9 @@ protected void operate() {
          */
         @Uninterruptible(reason = "Prevent pollution of the current thread's thread local JFR buffer.")
         private void changeEpoch() {
+            /* Process all unprocessed sampler buffers before changing the epoch. */
+            SamplerBuffersAccess.processSamplerBuffers();
+
             // Write unflushed data from the thread local buffers but do *not* reinitialize them
             // The thread local code will handle space reclamation on their own time
             for (IsolateThread thread = VMThreads.firstThread(); thread.isNonNull(); thread = VMThreads.nextThread(thread)) {

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

@@ -65,6 +65,7 @@ public final class JfrEvent {
     public static final JfrEvent JavaMonitorWait = create("jdk.JavaMonitorWait");
 
     private final long id;
+    private final String name;
 
     @Platforms(Platform.HOSTED_ONLY.class)
     private static JfrEvent create(String name) {
@@ -84,10 +85,16 @@ private static JfrEvent create(String name, Class<? extends BooleanSupplier> onl
     @Platforms(Platform.HOSTED_ONLY.class)
     private JfrEvent(String name) {
         this.id = JfrMetadataTypeLibrary.lookupPlatformEvent(name);
+        this.name = name;
     }
 
     @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
     public long getId() {
         return id;
     }
+
+    @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
+    public String getName() {
+        return name;
+    }
 }

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

@@ -112,7 +112,7 @@ public static boolean isInConfiguration(boolean allowPrinting) {
             throw UserError.abort("FlightRecorder cannot be used to profile the image generator on this platform. " +
                             "The image generator can only be profiled on platforms where FlightRecoder is also supported at run time.");
         }
-        boolean runtimeEnabled = VMInspectionOptions.hasJFRSupport();
+        boolean runtimeEnabled = VMInspectionOptions.hasJfrSupport();
         if (HOSTED_ENABLED && !runtimeEnabled) {
             if (allowPrinting) {
                 System.err.println("Warning: When FlightRecoder is used to profile the image generator, it is also automatically enabled in the native image at run time. " +

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

@@ -24,13 +24,13 @@
  */
 package com.oracle.svm.core.jfr;
 
-import com.oracle.svm.core.Uninterruptible;
 import org.graalvm.nativeimage.Platform;
 import org.graalvm.nativeimage.Platforms;
 import org.graalvm.nativeimage.StackValue;
 import org.graalvm.word.WordFactory;
 
 import com.oracle.svm.core.SubstrateUtil;
+import com.oracle.svm.core.Uninterruptible;
 import com.oracle.svm.core.code.FrameInfoQueryResult;
 import com.oracle.svm.core.hub.DynamicHub;
 import com.oracle.svm.core.jfr.traceid.JfrTraceIdEpoch;

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

@@ -42,11 +42,12 @@
 /**
  * A daemon thread that is created during JFR startup and torn down by
  * {@link SubstrateJVM#destroyJFR}.
- *
+ * <p>
  * It is used for persisting the {@link JfrGlobalMemory} buffers to a file and for processing the
  * pool of {@link SamplerBuffer}s collected in signal handler (see {@link SubstrateSigprofHandler}).
  * With that in mind, the thread is using {@link VMSemaphore} for a synchronization between threads
  * as it is async signal safe.
+ * </p>
  */
 public class JfrRecorderThread extends Thread {
     private static final int BUFFER_FULL_ENOUGH_PERCENTAGE = 50;

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

@@ -27,6 +27,7 @@
 import org.graalvm.nativeimage.Platform;
 import org.graalvm.nativeimage.Platforms;
 import org.graalvm.nativeimage.StackValue;
+import org.graalvm.nativeimage.c.function.CodePointer;
 import org.graalvm.nativeimage.c.struct.RawField;
 import org.graalvm.nativeimage.c.struct.RawStructure;
 import org.graalvm.nativeimage.c.struct.SizeOf;
@@ -35,6 +36,8 @@
 import org.graalvm.word.UnsignedWord;
 import org.graalvm.word.WordFactory;
 
+import com.oracle.svm.core.FrameAccess;
+import com.oracle.svm.core.NeverInline;
 import com.oracle.svm.core.SubstrateOptions;
 import com.oracle.svm.core.Uninterruptible;
 import com.oracle.svm.core.UnmanagedMemoryUtil;
@@ -47,6 +50,13 @@
 import com.oracle.svm.core.locks.VMMutex;
 import com.oracle.svm.core.sampler.SamplerBuffer;
 import com.oracle.svm.core.sampler.SamplerBufferAccess;
+import com.oracle.svm.core.sampler.SamplerSampleWriter;
+import com.oracle.svm.core.sampler.SamplerSampleWriterData;
+import com.oracle.svm.core.sampler.SamplerSampleWriterDataAccess;
+import com.oracle.svm.core.sampler.SamplerThreadLocal;
+import com.oracle.svm.core.sampler.SubstrateSigprofHandler;
+import com.oracle.svm.core.snippets.KnownIntrinsics;
+import com.oracle.svm.core.stack.JavaStackWalker;
 
 /**
  * Repository that collects all metadata about stacktraces.
@@ -88,14 +98,40 @@ public void teardown() {
         epochData1.teardown();
     }
 
-    @Uninterruptible(reason = "Epoch must not change while in this method.")
-    public long getStackTraceId(@SuppressWarnings("unused") int skipCount) {
+    @NeverInline("Starting a stack walk in the caller frame.")
+    @Uninterruptible(reason = "All code that accesses a sampler buffer must be uninterruptible.")
+    public long getStackTraceId(int skipCount) {
         assert maxDepth >= 0;
-        return 0;
+        long stackTraceId = 0;
+
+        /* Initialize stack walk. */
+        SamplerSampleWriterData data = StackValue.get(SamplerSampleWriterData.class);
+        SamplerThreadLocal.setSignalHandlerLocallyDisabled(true);
+        if (SamplerSampleWriterDataAccess.initialize(data, skipCount, maxDepth)) {
+            SamplerSampleWriter.begin(data);
+            /* Walk the stack. */
+            Pointer sp = KnownIntrinsics.readCallerStackPointer();
+            CodePointer ip = FrameAccess.singleton().readReturnAddress(sp);
+            if (JavaStackWalker.walkCurrentThread(sp, ip, SubstrateSigprofHandler.visitor()) || data.getTruncated()) {
+                acquireLock();
+                try {
+                    CIntPointer status = StackValue.get(CIntPointer.class);
+                    Pointer start = data.getStartPos().add(SamplerSampleWriter.getHeaderSize());
+                    stackTraceId = getStackTraceId(start, data.getCurrentPos(), data.getHashCode(), status, false);
+                    if (JfrStackTraceTableEntryStatus.get(status, JfrStackTraceTableEntryStatus.NEW)) {
+                        SamplerSampleWriter.end(data);
+                    }
+                } finally {
+                    releaseLock();
+                }
+            }
+        }
+        SamplerThreadLocal.setSignalHandlerLocallyDisabled(false);
+        return stackTraceId;
     }
 
     @Uninterruptible(reason = "All code that accesses a sampler buffer must be uninterruptible.")
-    public long getStackTraceId(Pointer start, Pointer end, int hashCode, CIntPointer isRecorded) {
+    public long getStackTraceId(Pointer start, Pointer end, int hashCode, CIntPointer status, boolean isSerializationInProgress) {
         JfrStackTraceEpochData epochData = getEpochData(false);
         JfrStackTraceTableEntry entry = StackValue.get(JfrStackTraceTableEntry.class);
 
@@ -107,7 +143,7 @@ public long getStackTraceId(Pointer start, Pointer end, int hashCode, CIntPointe
 
         JfrStackTraceTableEntry result = (JfrStackTraceTableEntry) epochData.visitedStackTraces.get(entry);
         if (result.isNonNull()) {
-            isRecorded.write(1);
+            JfrStackTraceTableEntryStatus.update(result, status, false, result.getSerialized(), isSerializationInProgress);
             return result.getId();
         } else {
             /* Replace the previous pointer with new one (entry size and hash remains the same). */
@@ -118,7 +154,7 @@ public long getStackTraceId(Pointer start, Pointer end, int hashCode, CIntPointe
             UnmanagedMemoryUtil.copy(start, to, size);
 
             JfrStackTraceTableEntry newEntry = (JfrStackTraceTableEntry) epochData.visitedStackTraces.getOrPut(entry);
-            isRecorded.write(0);
+            JfrStackTraceTableEntryStatus.update(newEntry, status, true, false, isSerializationInProgress);
             return newEntry.getId();
         }
     }
@@ -141,6 +177,7 @@ public void serializeStackTraceHeader(long stackTraceId, boolean isTruncated, in
         /* Stacktrace size. */
         JfrNativeEventWriter.putInt(data, stackTraceLength);
 
+        epochData.numberOfSerializedStackTraces++;
         JfrNativeEventWriter.commit(data);
 
         /*
@@ -195,13 +232,12 @@ public int write(JfrChunkWriter writer) {
     }
 
     private static int writeStackTraces(JfrChunkWriter writer, JfrStackTraceEpochData epochData) {
-        int stackTraceCount = epochData.visitedStackTraces.getSize();
-        if (stackTraceCount == 0) {
+        if (epochData.numberOfSerializedStackTraces == 0) {
             return EMPTY;
         }
 
         writer.writeCompressedLong(JfrType.StackTrace.getId());
-        writer.writeCompressedInt(stackTraceCount);
+        writer.writeCompressedInt(epochData.numberOfSerializedStackTraces);
         writer.write(epochData.stackTraceBuffer);
 
         return NON_EMPTY;
@@ -226,6 +262,12 @@ public interface JfrStackTraceTableEntry extends JfrVisited {
 
         @RawField
         void setSize(int size);
+
+        @RawField
+        boolean getSerialized();
+
+        @RawField
+        void setSerialized(boolean serialized);
     }
 
     public static final class JfrStackTraceTable extends AbstractUninterruptibleHashtable {
@@ -254,8 +296,31 @@ protected UninterruptibleEntry copyToHeap(UninterruptibleEntry valueOnStack) {
         }
     }
 
+    public static class JfrStackTraceTableEntryStatus {
+        public static final int NEW = 1;
+        public static final int SHOULD_SERIALIZE = NEW << 1;
+        public static final int SERIALIZED = SHOULD_SERIALIZE << 1;
+
+        @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
+        public static void update(JfrStackTraceTableEntry entry, CIntPointer status, boolean setNew, boolean isAlreadySerialized, boolean isSerializationInProgress) {
+            int isRecorded = setNew ? NEW : 0;
+            int shouldSerialize = !isAlreadySerialized ? SHOULD_SERIALIZE : 0;
+            int isSerialized = isAlreadySerialized ? SERIALIZED : 0;
+            status.write(isRecorded | shouldSerialize | isSerialized);
+            if (!entry.getSerialized() && isSerializationInProgress) {
+                entry.setSerialized(true);
+            }
+        }
+
+        @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
+        public static boolean get(CIntPointer status, int check) {
+            return (status.read() & check) != 0;
+        }
+    }
+
     private static class JfrStackTraceEpochData {
         private JfrBuffer stackTraceBuffer;
+        private int numberOfSerializedStackTraces;
         private final JfrStackTraceTable visitedStackTraces;
 
         @Platforms(Platform.HOSTED_ONLY.class)
@@ -265,6 +330,7 @@ private static class JfrStackTraceEpochData {
 
         void clear() {
             visitedStackTraces.clear();
+            numberOfSerializedStackTraces = 0;
             if (stackTraceBuffer.isNonNull()) {
                 JfrBufferAccess.reinitialize(stackTraceBuffer);
             }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jfr/events/EndChunkNativePeriodicEvents.java

@@ -27,12 +27,12 @@
 import java.util.Map;
 import java.util.Properties;
 
-import com.oracle.svm.core.jfr.JfrEventWriteStatus;
 import org.graalvm.nativeimage.StackValue;
 
 import com.oracle.svm.core.Uninterruptible;
 import com.oracle.svm.core.heap.Heap;
 import com.oracle.svm.core.jfr.JfrEvent;
+import com.oracle.svm.core.jfr.JfrEventWriteStatus;
 import com.oracle.svm.core.jfr.JfrNativeEventWriter;
 import com.oracle.svm.core.jfr.JfrNativeEventWriterData;
 import com.oracle.svm.core.jfr.JfrNativeEventWriterDataAccess;
@@ -55,7 +55,7 @@ private static String formatOSInformation() {
     }
 
     public static void emit() {
-        emitClassLoadingStatistics(Heap.getHeap().getClassCount(), 0);
+        emitClassLoadingStatistics(Heap.getHeap().getClassCount());
         emitJVMInformation(JVMInformation.getJVMInfo());
         emitOSInformation(formatOSInformation());
         emitInitialEnvironmentVariables(getEnvironmentVariables());
@@ -113,15 +113,15 @@ private static JfrEventWriteStatus emitInitialSystemProperty(JfrNativeEventWrite
     }
 
     @Uninterruptible(reason = "Accesses a JFR buffer.")
-    private static void emitClassLoadingStatistics(long loadedClassCount, long unloadedClassCount) {
+    private static void emitClassLoadingStatistics(long loadedClassCount) {
         if (SubstrateJVM.isRecording() && SubstrateJVM.get().isEnabled(JfrEvent.ClassLoadingStatistics)) {
             JfrNativeEventWriterData data = StackValue.get(JfrNativeEventWriterData.class);
             JfrNativeEventWriterDataAccess.initializeThreadLocalNativeBuffer(data);
 
             JfrNativeEventWriter.beginSmallEvent(data, JfrEvent.ClassLoadingStatistics);
             JfrNativeEventWriter.putLong(data, JfrTicks.elapsedTicks());
             JfrNativeEventWriter.putLong(data, loadedClassCount);
-            JfrNativeEventWriter.putLong(data, unloadedClassCount);
+            JfrNativeEventWriter.putLong(data, 0); /* unloadedClassCount */
             JfrNativeEventWriter.endSmallEvent(data);
         }
     }