8295651: JFR: 'jfr scrub' should summarize what was removed

Reviewed-by: mgronlun

Author: egahlin

src/jdk.jfr/share/classes/jdk/jfr/consumer/RecordedObject.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 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
@@ -28,13 +28,15 @@
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.io.StringWriter;
+import java.nio.file.Path;
 import java.time.Duration;
 import java.time.Instant;
 import java.time.OffsetDateTime;
 import java.time.temporal.ChronoUnit;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Objects;
+import java.util.function.Predicate;
 
 import jdk.jfr.Configuration;
 import jdk.jfr.EventType;
@@ -46,6 +48,7 @@
 import jdk.jfr.internal.consumer.JdkJfrConsumer;
 import jdk.jfr.internal.consumer.ObjectContext;
 import jdk.jfr.internal.consumer.ObjectFactory;
+import jdk.jfr.internal.consumer.filter.ChunkWriter.RemovedEvents;
 import jdk.jfr.internal.tool.PrettyWriter;
 
 /**
@@ -148,6 +151,11 @@ public MetadataEvent newMetadataEvent(List<EventType> previous, List<EventType>
                     List<Configuration> configurations) {
                 return new MetadataEvent(previous, current, configurations);
             }
+
+            @Override
+            public List<RemovedEvents> write(RecordingFile file, Path output, Predicate<RecordedEvent> filter) throws IOException {
+                return file.write(output, filter, true);
+            }
         };
         JdkJfrConsumer.setAccess(access);
     }

src/jdk.jfr/share/classes/jdk/jfr/consumer/RecordingFile.java

@@ -46,6 +46,7 @@
 import jdk.jfr.internal.consumer.ParserState;
 import jdk.jfr.internal.consumer.RecordingInput;
 import jdk.jfr.internal.consumer.filter.ChunkWriter;
+import jdk.jfr.internal.consumer.filter.ChunkWriter.RemovedEvents;
 
 /**
  * A recording file.
@@ -229,12 +230,18 @@ public void close() throws IOException {
     public void write(Path destination, Predicate<RecordedEvent> filter) throws IOException {
         Objects.requireNonNull(destination, "destination");
         Objects.requireNonNull(filter, "filter");
-        try (ChunkWriter cw = new ChunkWriter(file.toPath(), destination, filter)) {
+        write(destination, filter, false);
+    }
+
+    // package private
+    List<RemovedEvents> write(Path destination, Predicate<RecordedEvent> filter, boolean collectResults) throws IOException {
+        try (ChunkWriter cw = new ChunkWriter(file.toPath(), destination, filter, collectResults)) {
             try (RecordingFile rf = new RecordingFile(cw)) {
                 while (rf.hasMoreEvents()) {
                     rf.readEvent();
                 }
             }
+            return cw.getRemovedEventTypes();
         }
     }
 

src/jdk.jfr/share/classes/jdk/jfr/internal/LongMap.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 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
@@ -25,7 +25,9 @@
 
 package jdk.jfr.internal;
 
+import java.util.ArrayList;
 import java.util.BitSet;
+import java.util.List;
 import java.util.function.Consumer;
 import java.util.function.LongConsumer;
 
@@ -265,4 +267,15 @@ public String toString() {
         }
         return sb.toString();
     }
+
+    public List<T> values() {
+        List<T> list = new ArrayList<>(count);
+        for (int i = 0; i < keys.length; i++) {
+            T o = objects[i];
+            if (o != null) {
+                list.add(o);
+            }
+        }
+        return list;
+    }
 }

src/jdk.jfr/share/classes/jdk/jfr/internal/consumer/JdkJfrConsumer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 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
@@ -26,8 +26,10 @@
 package jdk.jfr.internal.consumer;
 
 import java.io.IOException;
+import java.nio.file.Path;
 import java.util.Comparator;
 import java.util.List;
+import java.util.function.Predicate;
 
 import jdk.jfr.Configuration;
 import jdk.jfr.EventType;
@@ -43,6 +45,7 @@
 import jdk.jfr.consumer.RecordedThreadGroup;
 import jdk.jfr.consumer.RecordingFile;
 import jdk.jfr.internal.Type;
+import jdk.jfr.internal.consumer.filter.ChunkWriter.RemovedEvents;;
 
 /*
  * Purpose of this class is to give package private access to
@@ -105,4 +108,5 @@ public static JdkJfrConsumer instance() {
 
     public abstract MetadataEvent newMetadataEvent(List<EventType> previous, List<EventType> current, List<Configuration> configuration);
 
+    public abstract List<RemovedEvents> write(RecordingFile file, Path output, Predicate<RecordedEvent> filter) throws IOException;
 }

src/jdk.jfr/share/classes/jdk/jfr/internal/consumer/filter/ChunkWriter.java

@@ -32,6 +32,7 @@
 import java.util.Deque;
 import java.util.Map;
 import java.util.HashMap;
+import java.util.List;
 import java.util.function.Predicate;
 
 import jdk.jfr.consumer.RecordedEvent;
@@ -51,23 +52,48 @@
  * All positional values are relative to file start, not the chunk.
  */
 public final class ChunkWriter implements Closeable {
+    public static class RemovedEvents implements Comparable<RemovedEvents> {
+        public final String name;
+        private long count;
+        private long removed;
+
+        private RemovedEvents(String name) {
+            this.name = name;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public String share() {
+            return removed + "/" + count;
+        }
+
+        @Override
+        public int compareTo(RemovedEvents that) {
+            return this.getName().compareTo(that.getName());
+        }
+    }
     private LongMap<Constants> pools = new LongMap<>();
     private final Deque<CheckpointEvent> checkpoints = new ArrayDeque<>();
     private final Path destination;
     private final RecordingInput input;
     private final RecordingOutput output;
     private final Predicate<RecordedEvent> filter;
     private final Map<String, Long> waste = new HashMap<>();
+    private final LongMap<RemovedEvents> removedEvents = new LongMap<>();
+    private final boolean collectResults;
 
     private long chunkStartPosition;
     private boolean chunkComplete;
     private long lastCheckpoint;
 
-    public ChunkWriter(Path source, Path destination, Predicate<RecordedEvent> filter) throws IOException {
+    public ChunkWriter(Path source, Path destination, Predicate<RecordedEvent> filter, boolean collectResults) throws IOException {
         this.destination = destination;
         this.output = new RecordingOutput(destination.toFile());
         this.input = new RecordingInput(source.toFile());
         this.filter = filter;
+        this.collectResults = collectResults;
     }
 
     Constants getPool(Type type) {
@@ -87,7 +113,25 @@ public CheckpointEvent newCheckpointEvent(long startPosition) {
     }
 
     public boolean accept(RecordedEvent event) {
-        return filter.test(event);
+        if (!collectResults) {
+            return filter.test(event);
+        }
+        long id = event.getEventType().getId();
+        RemovedEvents r = removedEvents.get(id);
+        if (r == null) {
+            r = new RemovedEvents(event.getEventType().getName());
+            removedEvents.put(id, r);
+        }
+        r.count++;
+        if (filter.test(event)) {
+            return true;
+        }
+        r.removed++;
+        return false;
+    }
+
+    public List<RemovedEvents> getRemovedEventTypes() {
+        return removedEvents.values().stream().filter(r -> r.removed > 0).sorted().toList();
     }
 
     public void touch(Object object) {

src/jdk.jfr/share/classes/jdk/jfr/internal/tool/Command.java

@@ -318,6 +318,10 @@ protected final void println(String text) {
         System.out.println(text);
     }
 
+    protected final void printf(String text, Object ... args) {
+        System.out.printf(text, args);
+    }
+
     public static void checkCommonError(Deque<String> options, String typo, String correct) throws UserSyntaxException {
         if (typo.equals(options.peek())) {
             throw new UserSyntaxException("unknown option " + typo + ", did you mean " + correct + "?");

src/jdk.jfr/share/classes/jdk/jfr/internal/tool/Scrub.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 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
@@ -37,6 +37,8 @@
 import jdk.jfr.EventType;
 import jdk.jfr.consumer.RecordedEvent;
 import jdk.jfr.consumer.RecordingFile;
+import jdk.jfr.internal.consumer.JdkJfrConsumer;
+import jdk.jfr.internal.consumer.filter.ChunkWriter.RemovedEvents;
 import jdk.jfr.internal.util.UserDataException;
 import jdk.jfr.internal.util.UserSyntaxException;
 
@@ -141,12 +143,26 @@ public void execute(Deque<String> options) throws UserSyntaxException, UserDataE
         try (RecordingFile rf = new RecordingFile(input)) {
             List<EventType> types = rf.readEventTypes();
             Predicate<RecordedEvent> filter = createFilter(options, types);
-            rf.write(output, filter);
+            List<RemovedEvents> result = JdkJfrConsumer.instance().write(rf, output, filter);
+            println("Scrubbed recording file written to:");
+            println(output.toRealPath().toString());
+            if (result.isEmpty()) {
+                println("No events removed.");
+                return;
+            }
+            int maxName = 0;
+            int maxShare = 0;
+            for (RemovedEvents re : result) {
+                maxName = Math.max(maxName, re.getName().length());
+                maxShare = Math.max(maxShare, re.share().length());
+            }
+            println("Removed events:");
+            for (RemovedEvents re : result) {
+                printf("%-" + maxName + "s %" + maxShare + "s\n", re.getName(), re.share());
+            }
         } catch (IOException ioe) {
             couldNotReadError(input, ioe);
         }
-        println("Scrubbed recording file written to:");
-        println(output.toAbsolutePath().toString());
     }
 
     private Predicate<RecordedEvent> createFilter(Deque<String> options, List<EventType> types) throws UserSyntaxException, UserDataException {

src/jdk.jfr/share/classes/jdk/jfr/internal/tool/Summary.java

@@ -152,7 +152,7 @@ private void printInformation(Path p) throws IOException {
             println(typeHeader + " ".repeat(minWidth - typeHeader.length()) + header);
             println("=".repeat(minWidth + header.length()));
             for (Statistics s : statsList) {
-                System.out.printf(" %-" + minWidth + "s%10d  %12d\n", s.name, s.count, s.size);
+                printf(" %-" + minWidth + "s%10d  %12d\n", s.name, s.count, s.size);
             }
         }
     }

test/jdk/jdk/jfr/tool/TestScrub.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 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
@@ -69,9 +69,16 @@ public static void main(String[] args) throws Throwable {
 
         try (Recording r = new Recording()) {
             r.start();
-            emit(100, "India", TigerEvent.class);
-            emit(100, "Namibia", ZebraEvent.class);
-            emit(10000, "Lake Tanganyika", TigerfishEvent.class);
+            emit(50, "India", TigerEvent.class);
+            emit(50, "Namibia", ZebraEvent.class);
+            emit(5000, "Lake Tanganyika", TigerfishEvent.class);
+            // Force rotation
+            try (Recording s = new Recording()) {
+               s.start();
+            }
+            emit(50, "India", TigerEvent.class);
+            emit(50, "Namibia", ZebraEvent.class);
+            emit(5000, "Lake Tanganyika", TigerfishEvent.class);
             r.stop();
             r.dump(file);
         }
@@ -89,6 +96,7 @@ public static void main(String[] args) throws Throwable {
         testThreadInclude(file);
 
         testMissingEventType(file);
+        testSummary(file);
     }
 
     private static void testInputOutput(Path file) throws Throwable {
@@ -275,6 +283,23 @@ private static void testMissingEventType(Path input) throws Throwable {
         Files.delete(output);
     }
 
+
+    private static void testSummary(Path file) throws Throwable {
+        String inputFile = file.toAbsolutePath().toString();
+
+        String removedZebras = Path.of("removed-zebras.jfr").toAbsolutePath().toString();
+        var outp = ExecuteHelper.jfr("scrub", "--exclude-events", "Zebra", inputFile, removedZebras);
+        outp.shouldContain("Removed events:");
+        outp.shouldContain("example.Zebra 100/100");
+        outp.shouldNotContain("Tiger");
+        outp.shouldNotContain("No events removed");
+
+        String noneRemoved = Path.of("none-removed.jfr").toAbsolutePath().toString();
+        outp = ExecuteHelper.jfr("scrub", "--exclude-events", "jdk.JVMInformation", inputFile, noneRemoved);
+        outp.shouldContain("No events removed");
+        outp.shouldNotContain("jdk.JVMInformation");
+    }
+
     private static void assertNotThread(RecordedEvent event, String... threadNames) {
         String s = event.getThread().getJavaName();
         for (String threadName : threadNames) {