8351594: JFR: Rate-limited sampling of Java events

src/java.base/share/classes/java/io/FileInputStream.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1994, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1994, 2025, 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
@@ -217,10 +217,12 @@ private int traceRead0() throws IOException {
                 bytesRead = 1;
             }
         } finally {
-            long duration = FileReadEvent.timestamp() - start;
-            if (FileReadEvent.shouldCommit(duration)) {
+            long end = FileReadEvent.timestamp();
+            long duration = end - start;
+            if (FileReadEvent.shouldThrottleCommit(duration, end)) {
                 FileReadEvent.commit(start, duration, path, bytesRead, endOfFile);
             }
+
         }
         return result;
     }
@@ -241,8 +243,9 @@ private int traceReadBytes(byte b[], int off, int len) throws IOException {
             start = FileReadEvent.timestamp();
             bytesRead = readBytes(b, off, len);
         } finally {
-            long duration = FileReadEvent.timestamp() - start;
-            if (FileReadEvent.shouldCommit(duration)) {
+            long end = FileReadEvent.timestamp();
+            long duration = end - start;
+            if (FileReadEvent.shouldThrottleCommit(duration, end)) {
                 if (bytesRead < 0) {
                     FileReadEvent.commit(start, duration, path, 0L, true);
                 } else {

src/java.base/share/classes/java/io/FileOutputStream.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1994, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1994, 2025, 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
@@ -272,8 +272,9 @@ private void traceWrite(int b, boolean append) throws IOException {
             write(b, append);
             bytesWritten = 1;
         } finally {
-            long duration = FileWriteEvent.timestamp() - start;
-            if (FileWriteEvent.shouldCommit(duration)) {
+            long end = FileWriteEvent.timestamp();
+            long duration = end - start;
+            if (FileWriteEvent.shouldThrottleCommit(duration, end)) {
                 FileWriteEvent.commit(start, duration, path, bytesWritten);
             }
         }
@@ -316,8 +317,9 @@ private void traceWriteBytes(byte b[], int off, int len, boolean append) throws
             writeBytes(b, off, len, append);
             bytesWritten = len;
         } finally {
-            long duration = FileWriteEvent.timestamp() - start;
-            if (FileWriteEvent.shouldCommit(duration)) {
+            long end = FileWriteEvent.timestamp();
+            long duration = end - start;
+            if (FileWriteEvent.shouldThrottleCommit(duration, end)) {
                 FileWriteEvent.commit(start, duration, path, bytesWritten);
             }
         }

src/java.base/share/classes/java/io/RandomAccessFile.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1994, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1994, 2025, 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
@@ -378,8 +378,9 @@ private int traceRead0() throws IOException {
                 bytesRead = 1;
             }
         } finally {
-            long duration = FileReadEvent.timestamp() - start;
-            if (FileReadEvent.shouldCommit(duration)) {
+            long end = FileReadEvent.timestamp();
+            long duration = end - start;
+            if (FileReadEvent.shouldThrottleCommit(duration, end)) {
                 FileReadEvent.commit(start, duration, path, bytesRead, endOfFile);
             }
         }
@@ -409,8 +410,9 @@ private int traceReadBytes0(byte b[], int off, int len) throws IOException {
             start = FileReadEvent.timestamp();
             bytesRead = readBytes0(b, off, len);
         } finally {
-            long duration = FileReadEvent.timestamp() - start;
-            if (FileReadEvent.shouldCommit(duration)) {
+            long end = FileReadEvent.timestamp();
+            long duration = end - start;
+            if (FileReadEvent.shouldThrottleCommit(duration, end)) {
                 if (bytesRead < 0) {
                     FileReadEvent.commit(start, duration, path, 0L, true);
                 } else {
@@ -588,8 +590,9 @@ private void traceImplWrite(int b) throws IOException {
             implWrite(b);
             bytesWritten = 1;
         } finally {
-            long duration = FileWriteEvent.timestamp() - start;
-            if (FileWriteEvent.shouldCommit(duration)) {
+            long end = FileWriteEvent.timestamp();
+            long duration =  end - start;
+            if (FileWriteEvent.shouldThrottleCommit(duration, end)) {
                 FileWriteEvent.commit(start, duration, path, bytesWritten);
             }
         }
@@ -630,8 +633,9 @@ private void traceImplWriteBytes(byte b[], int off, int len) throws IOException
             implWriteBytes(b, off, len);
             bytesWritten = len;
         } finally {
-            long duration = FileWriteEvent.timestamp() - start;
-            if (FileWriteEvent.shouldCommit(duration)) {
+            long end = FileWriteEvent.timestamp();
+            long duration = end - start;
+            if (FileWriteEvent.shouldThrottleCommit(duration, end)) {
                 FileWriteEvent.commit(start, duration, path, bytesWritten);
             }
         }

src/java.base/share/classes/java/lang/Throwable.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1994, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1994, 2025, 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
@@ -121,7 +121,7 @@ public class Throwable implements Serializable {
      * Flag set by jdk.internal.event.JFRTracing to indicate if
      * exceptions should be traced by JFR.
      */
-    static volatile boolean jfrTracing;
+    static boolean jfrTracing;
 
     /**
      * The JVM saves some indication of the stack backtrace in this slot.

src/java.base/share/classes/java/net/Socket.java

@@ -965,8 +965,9 @@ public int read(byte[] b, int off, int len) throws IOException {
             }
             long start = SocketReadEvent.timestamp();
             int nbytes = implRead(b, off, len);
-            long duration = SocketReadEvent.timestamp() - start;
-            if (SocketReadEvent.shouldCommit(duration)) {
+            long end = SocketReadEvent.timestamp();
+            long duration = end - start;
+            if (SocketReadEvent.shouldThrottleCommit(duration, end)) {
                 SocketReadEvent.emit(start, duration, nbytes, parent.getRemoteSocketAddress(), getSoTimeout());
             }
             return nbytes;
@@ -1081,8 +1082,9 @@ public void write(byte[] b, int off, int len) throws IOException {
             }
             long start = SocketWriteEvent.timestamp();
             implWrite(b, off, len);
-            long duration = SocketWriteEvent.timestamp() - start;
-            if (SocketWriteEvent.shouldCommit(duration)) {
+            long end = SocketWriteEvent.timestamp();
+            long duration = end - start;
+            if (SocketWriteEvent.shouldThrottleCommit(duration, end)) {
                 SocketWriteEvent.emit(start, duration, len, parent.getRemoteSocketAddress());
             }
         }

src/java.base/share/classes/jdk/internal/event/ExceptionThrownEvent.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2025, 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
@@ -31,6 +31,11 @@ public final class ExceptionThrownEvent extends Event {
     public String message;
     public Class<?> thrownClass;
 
+    public static boolean shouldThrottleCommit(long timestamp) {
+        // Generated by JFR
+        return false;
+    }
+
     public static void commit(long start, String message, Class<?> thrownClass) {
         // Generated by JFR
     }

src/java.base/share/classes/jdk/internal/event/FileReadEvent.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2024, 2025, 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
@@ -45,7 +45,7 @@ public static long timestamp() {
         return 0L;
     }
 
-    public static boolean shouldCommit(long duration) {
+    public static boolean shouldThrottleCommit(long duration, long timestamp) {
         // Generated by JFR
         return false;
     }

src/java.base/share/classes/jdk/internal/event/FileWriteEvent.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2025, 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
@@ -44,7 +44,7 @@ public static long timestamp() {
         return 0L;
     }
 
-    public static boolean shouldCommit(long duration) {
+    public static boolean shouldThrottleCommit(long duration, long timestamp) {
         // Generated by JFR
         return false;
     }

src/java.base/share/classes/jdk/internal/event/SocketReadEvent.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2025, 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
@@ -76,7 +76,7 @@ public static void commit(long start, long duration, String host, String address
      * @param duration  time in nanoseconds to complete the operation
      * @return  true if the event should be commited
      */
-    public static boolean shouldCommit(long duration) {
+    public static boolean shouldThrottleCommit(long duration, long timestamp) {
         // Generated by JFR
         return false;
     }
@@ -118,8 +118,9 @@ public static long timestamp() {
      * @param timeout  maximum time to wait
      */
     public static void offer(long start, long nbytes, SocketAddress remote, long timeout) {
-        long duration = timestamp() - start;
-        if (shouldCommit(duration)) {
+        long end = timestamp();
+        long duration = end - start;
+        if (shouldThrottleCommit(duration, end)) {
             emit(start, duration, nbytes, remote, timeout);
         }
     }

src/java.base/share/classes/jdk/internal/event/SocketWriteEvent.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2025, 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
@@ -71,7 +71,7 @@ public static void commit(long start, long duration, String host, String address
      * @param duration  time in nanoseconds to complete the operation
      * @return  true if the event should be commited
      */
-    public static boolean shouldCommit(long duration) {
+    public static boolean shouldThrottleCommit(long duration, long timestamp) {
         // Generated by JFR
         return false;
     }
@@ -104,16 +104,17 @@ public static long timestamp() {
      * The duration of the operation is computed using the current
      * timestamp and the given start time.  If the duration is meets
      * or exceeds the configured value (determined by calling the generated method
-     * {@link #shouldCommit(long)}), an event will be emitted by calling
+     * {@link #shouldThrottleCommit(long)}), an event will be emitted by calling
      * {@link #emit(long, long, long, SocketAddress)}.
      *
      * @param start  the start time
      * @param bytesWritten  how many bytes were sent
      * @param remote  the address of the remote socket being written to
      */
     public static void offer(long start, long bytesWritten, SocketAddress remote) {
-        long duration = timestamp() - start;
-        if (shouldCommit(duration)) {
+        long end = timestamp();
+        long duration = end - start;
+        if (shouldThrottleCommit(duration, end)) {
             emit(start, duration, bytesWritten, remote);
         }
     }

src/java.base/share/classes/jdk/internal/event/ThrowableTracer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2025, 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
@@ -37,22 +37,24 @@ public static void traceError(Class<?> clazz, String message) {
         if (OutOfMemoryError.class.isAssignableFrom(clazz)) {
             return;
         }
-
-        if (ErrorThrownEvent.enabled()) {
+        if (ErrorThrownEvent.enabled() || ExceptionThrownEvent.enabled()) {
             long timestamp = ErrorThrownEvent.timestamp();
-            ErrorThrownEvent.commit(timestamp, message, clazz);
-        }
-        if (ExceptionThrownEvent.enabled()) {
-            long timestamp = ExceptionThrownEvent.timestamp();
-            ExceptionThrownEvent.commit(timestamp, message, clazz);
+            if (ErrorThrownEvent.enabled()) {
+                ErrorThrownEvent.commit(timestamp, message, clazz);
+            }
+            if (ExceptionThrownEvent.shouldThrottleCommit(timestamp)) {
+                ExceptionThrownEvent.commit(timestamp, message, clazz);
+            }
         }
         numThrowables.incrementAndGet();
     }
 
     public static void traceThrowable(Class<?> clazz, String message) {
         if (ExceptionThrownEvent.enabled()) {
-            long timestamp = ExceptionThrownEvent.timestamp();
-            ExceptionThrownEvent.commit(timestamp, message, clazz);
+            long timestamp = ErrorThrownEvent.timestamp();
+            if (ExceptionThrownEvent.shouldThrottleCommit(timestamp)) {
+                ExceptionThrownEvent.commit(timestamp, message, clazz);
+            }
         }
         numThrowables.incrementAndGet();
     }

src/java.base/share/classes/sun/nio/ch/FileChannelImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2025, 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
@@ -269,8 +269,9 @@ private int traceImplRead(ByteBuffer dst) throws IOException {
             start = FileReadEvent.timestamp();
             bytesRead = implRead(dst);
         } finally {
-            long duration = FileReadEvent.timestamp() - start;
-            if (FileReadEvent.shouldCommit(duration)) {
+            long end = FileReadEvent.timestamp();
+            long duration = end - start;
+            if (FileReadEvent.shouldThrottleCommit(duration, end)) {
                 if (bytesRead < 0) {
                     FileReadEvent.commit(start, duration, path, 0L, true);
                 } else {
@@ -331,8 +332,9 @@ private long traceImplRead(ByteBuffer[] dsts, int offset, int length) throws IOE
             start = FileReadEvent.timestamp();
             bytesRead = implRead(dsts, offset, length);
         } finally {
-            long duration = FileReadEvent.timestamp() - start;
-            if (FileReadEvent.shouldCommit(duration)) {
+            long end = FileReadEvent.timestamp();
+            long duration = end - start;
+            if (FileReadEvent.shouldThrottleCommit(duration, end)) {
                 if (bytesRead < 0) {
                     FileReadEvent.commit(start, duration, path, 0L, true);
                 } else {
@@ -390,8 +392,9 @@ private int traceImplWrite(ByteBuffer src) throws IOException {
             start = FileWriteEvent.timestamp();
             bytesWritten = implWrite(src);
         } finally {
-            long duration = FileWriteEvent.timestamp() - start;
-            if (FileWriteEvent.shouldCommit(duration)) {
+            long end = FileWriteEvent.timestamp();
+            long duration = end - start;
+            if (FileWriteEvent.shouldThrottleCommit(duration, end)) {
                 long bytes = bytesWritten > 0 ? bytesWritten : 0;
                 FileWriteEvent.commit(start, duration, path, bytes);
             }
@@ -446,8 +449,9 @@ private long traceImplWrite(ByteBuffer[] srcs, int offset, int length) throws IO
             start = FileWriteEvent.timestamp();
             bytesWritten = implWrite(srcs, offset, length);
         } finally {
-            long duration = FileWriteEvent.timestamp() - start;
-            if (FileWriteEvent.shouldCommit(duration)) {
+            long end = FileWriteEvent.timestamp();
+            long duration = end - start;
+            if (FileWriteEvent.shouldThrottleCommit(duration, end)) {
                 long bytes = bytesWritten > 0 ? bytesWritten : 0;
                 FileWriteEvent.commit(start, duration, path, bytes);
             }
@@ -1204,8 +1208,9 @@ private int traceImplRead(ByteBuffer dst, long position) throws IOException {
             start = FileReadEvent.timestamp();
             bytesRead = implRead(dst, position);
         } finally {
-            long duration = FileReadEvent.timestamp() - start;
-            if (FileReadEvent.shouldCommit(duration)) {
+            long end = FileReadEvent.timestamp();
+            long duration = end - start;
+            if (FileReadEvent.shouldThrottleCommit(duration, end)) {
                 if (bytesRead < 0) {
                     FileReadEvent.commit(start, duration, path, 0L, true);
                 } else {
@@ -1276,8 +1281,9 @@ private int traceImplWrite(ByteBuffer src, long position) throws IOException {
             start = FileWriteEvent.timestamp();
             bytesWritten = implWrite(src, position);
         } finally {
-            long duration = FileWriteEvent.timestamp() - start;
-            if (FileWriteEvent.shouldCommit(duration)) {
+            long end = FileWriteEvent.timestamp();
+            long duration = end - start;
+            if (FileWriteEvent.shouldThrottleCommit(duration, end)) {
                 long bytes = bytesWritten > 0 ? bytesWritten : 0;
                 FileWriteEvent.commit(start, duration, path, bytes);
             }