8334765: JFR: Log chunk waste

Reviewed-by: mgronlun
dfuch · Jun 24, 2024 · 55c7969 · 55c7969
1 parent b2930c5
commit 55c7969
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Showing 2 changed files with 30 additions and 3 deletions.
diff --git a/src/jdk.jfr/share/classes/jdk/jfr/internal/consumer/filter/ChunkWriter.java b/src/jdk.jfr/share/classes/jdk/jfr/internal/consumer/filter/ChunkWriter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, 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
@@ -30,6 +30,8 @@
 import java.nio.file.Path;
 import java.util.ArrayDeque;
 import java.util.Deque;
+import java.util.Map;
+import java.util.HashMap;
 import java.util.function.Predicate;
 
 import jdk.jfr.consumer.RecordedEvent;
@@ -56,6 +58,7 @@ public final class ChunkWriter implements Closeable {
     private final RecordingInput input;
     private final RecordingOutput output;
     private final Predicate<RecordedEvent> filter;
+    private final Map<String, Long> waste = new HashMap<>();
 
     private long chunkStartPosition;
     private boolean chunkComplete;
@@ -178,6 +181,16 @@ public void endChunk(ChunkHeader header) throws IOException {
         pools = new LongMap<>();
         chunkComplete = true;
         lastCheckpoint = 0;
+        if (Logger.shouldLog(LogTag.JFR_SYSTEM_PARSER, LogLevel.DEBUG)) {
+            // Log largest waste first
+            waste.entrySet().stream()
+                 .sorted((a, b) -> b.getValue().compareTo(a.getValue()))
+                 .forEach(entry -> {
+                     String msg = "Total chunk waste by " + entry.getKey() + ": " + entry.getValue() + " bytes.";
+                     Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.DEBUG, msg);
+                 });
+        }
+        waste.clear();
     }
 
     private void writeMetadataEvent(ChunkHeader header) throws IOException {
@@ -216,6 +229,20 @@ private void write(CheckpointEvent event, long delta) throws IOException {
                 }
             }
         }
+        if (Logger.shouldLog(LogTag.JFR_SYSTEM_PARSER, LogLevel.DEBUG)) {
+            for (CheckpointPool pool : event.getPools()) {
+                for (PoolEntry pe : pool.getEntries()) {
+                    if (!pe.isTouched()) {
+                        String name = pe.getType().getName();
+                        long amount = pe.getEndPosition() - pe.getStartPosition();
+                        waste.merge(pe.getType().getName(), amount, Long::sum);
+                        String msg = "Unreferenced constant ID " + pe.getId() +
+                                     " of type "+ name + " using " + amount + " bytes.";
+                        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.TRACE, msg);
+                    }
+                }
+            }
+        }
         long endPosition = output.position();
         long size = endPosition - startPosition;
         output.position(startPosition);

diff --git a/test/jdk/jdk/jfr/jvm/TestWaste.java b/test/jdk/jdk/jfr/jvm/TestWaste.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, 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
@@ -47,7 +47,7 @@
  * @requires vm.hasJFR
  * @library /test/lib /test/jdk
  * @modules jdk.jfr/jdk.jfr.internal.test
- * @run main/othervm -XX:TLABSize=2k jdk.jfr.jvm.TestWaste
+ * @run main/othervm -Xlog:jfr+system+parser=debug -XX:TLABSize=2k jdk.jfr.jvm.TestWaste
  */
 public class TestWaste {
     static List<Object> list = new LinkedList<>();