microsoft · obourgain · Nov 13, 2025
diff --git a/parser/src/main/java/com/microsoft/gctoolkit/parser/GCLogParser.java b/parser/src/main/java/com/microsoft/gctoolkit/parser/GCLogParser.java
@@ -30,11 +30,6 @@ public abstract class GCLogParser implements DataSourceParser, SharedPatterns {
      */
     public static final String END_OF_DATA_SENTINEL = GCLogFile.END_OF_DATA_SENTINEL;
 
-    // TODO: GCID_COUNTER should be in SharedPatterns, not here.
-    /**
-     * Rule for parsing the GCID counter.
-     */
-    public static final GCParseRule GCID_COUNTER = new GCParseRule("GCID_COUNTER", " GC\\((\\d+)\\) ");
     private JVMEventChannel consumer;
     protected Diary diary;
     private DateTimeStamp clock = new DateTimeStamp(DateTimeStamp.EPOC, 0.0d);
@@ -246,9 +241,54 @@ MemoryPoolSummary extractPermGenRecord(GCLogTrace trace) {
      * @param line the line to parse.
      * @return the extracted GCID, or -1 if not found.
      */
-    int extractGCID(String line) {
-        GCLogTrace trace = GCID_COUNTER.parse(line);
-        return (trace != null) ? trace.getIntegerGroup(1) : -1;
+    static int extractGCID(String line) {
+        long packed = extractGCCycleIdAndTextualLength(line);
+        if (packed == -1) {
+            return -1;
+        }
+        return extractGCCycleId(packed);
+    }
+
+    /**
+     * Returns a packed long containing two ints:
+     * - the GC cycle id in the high bytes
+     * - the length of the text containing the GC cycle id,e.g. 'GC(10)'
+     * See {@link #extractGCCycleId(long)} and {@link #extractGCCycleIdTextualLength(long)}
+     */
+    protected static long extractGCCycleIdAndTextualLength(String line) {
+        if (!line.contains("GC(")) {
+            return -1;
+        }
+        // [2025-10-21T16:44:29.311+0200][3645.640s] GC(35) Pause Young (Allocation Failure)
+        // we search for the value between parenthesis
+        int start = line.indexOf('(');
+        int end = line.indexOf(')', start);
+        if (start == -1 || end == -1) {
+            return -1;
+        }
+        try {
+            int gcId = Integer.parseInt(line, start + 1, end, 10);
+            // add the closing parenthesis to the length
+            int endToReturn = end + 1;
+            // pack the two ints in a long
+            return (((long) gcId) << 32) | (endToReturn & 0xFFFFFFFFL);
+        } catch (Exception e) {
+            throw new RuntimeException("Failed to extract gc cycle id from " + line, e);
+        }
+    }
+
+    protected static int extractGCCycleId(long packedGcCycleIdAndEnd) {
+        if (packedGcCycleIdAndEnd == -1) {
+            return -1;
+        }
+        return (int) (packedGcCycleIdAndEnd >> 32);
+    }
+
+    protected static int extractGCCycleIdTextualLength(long packedGcCycleIdAndEnd) {
+        if (packedGcCycleIdAndEnd == -1) {
+            return 0;
+        }
+        return (int) packedGcCycleIdAndEnd;
     }
 
     /**
@@ -281,4 +321,4 @@ public void publishTo(JVMEventChannel channel) {
     public ChannelName channel() {
         return ChannelName.DATA_SOURCE;
     }
-}
+}
diff --git a/parser/src/main/java/com/microsoft/gctoolkit/parser/UnifiedG1GCParser.java b/parser/src/main/java/com/microsoft/gctoolkit/parser/UnifiedG1GCParser.java
@@ -4,11 +4,7 @@
 
 import com.microsoft.gctoolkit.GCToolKit;
 import com.microsoft.gctoolkit.aggregator.EventSource;
-import com.microsoft.gctoolkit.event.CPUSummary;
-import com.microsoft.gctoolkit.event.GarbageCollectionTypes;
-import com.microsoft.gctoolkit.event.MalformedEvent;
-import com.microsoft.gctoolkit.event.MemoryPoolSummary;
-import com.microsoft.gctoolkit.event.RegionSummary;
+import com.microsoft.gctoolkit.event.*;
 import com.microsoft.gctoolkit.event.g1gc.G1ConcurrentUndoCycle;
 import com.microsoft.gctoolkit.event.g1gc.G1GCConcurrentEvent;
 import com.microsoft.gctoolkit.event.g1gc.G1GCEvent;
@@ -24,7 +20,6 @@
 import com.microsoft.gctoolkit.parser.unified.UnifiedG1GCPatterns;
 import com.microsoft.gctoolkit.time.DateTimeStamp;
 
-import java.util.AbstractMap;
 import java.util.LinkedList;
 import java.util.Map;
 import java.util.Queue;
@@ -33,8 +28,6 @@
 import java.util.function.BiConsumer;
 import java.util.logging.Level;
 import java.util.logging.Logger;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 
 import static com.microsoft.gctoolkit.event.GarbageCollectionTypes.fromLabel;
 
@@ -177,36 +170,38 @@ protected void process(String line) {
             parse(line);
     }
 
-    private static final Pattern gcIdPattern = GCLogParser.GCID_COUNTER.pattern();
-
     private void parse(String line) {
 
         // Minor optimization. The parse rule only applies to what comes after the GC ID.
         final int end;
         final int gcid;
-        final Matcher gcIdMatcher = gcIdPattern.matcher(line);
-        if (gcIdMatcher.find()) {
-            gcid = Integer.parseInt(gcIdMatcher.group(1));
-            end = gcIdMatcher.end();
+        long packedGcCycleIdAndEnd = extractGCCycleIdAndTextualLength(line);
+        if (packedGcCycleIdAndEnd != -1) {
+            gcid = extractGCCycleId(packedGcCycleIdAndEnd);
+            end = extractGCCycleIdTextualLength(packedGcCycleIdAndEnd);
         } else {
             gcid = -1;
             end = 0;
         }
 
         final String lineAfterGcId = line.substring(end);
-        parseRules.stream()
-                .map(Map.Entry::getKey)
-                .map(rule -> new AbstractMap.SimpleEntry<>(rule, rule.parse(lineAfterGcId)))
-                .filter(tuple -> tuple.getValue() != null)
-                .findAny()
-                .ifPresentOrElse(
-                        tuple -> {
-                            // Typically, "end" will be greater than zero, but not always.
-                            setForwardReference(gcid, end > 0 ? line.substring(0, end) : line);
-                            applyRule(tuple.getKey(), tuple.getValue(), line);
-                        },
-                        () -> log(line)
-                );
+        GCParseRule matchedParseRule = null;
+        GCLogTrace parsed = null;
+        for (Map.Entry<GCParseRule, BiConsumer<GCLogTrace, String>> entry : parseRules.entrySet()) {
+            GCParseRule rule = entry.getKey();
+            parsed = rule.parse(lineAfterGcId);
+            if (parsed != null) {
+                matchedParseRule = rule;
+                break;
+            }
+        }
+        if (parsed != null) {
+            // Typically, "end" will be greater than zero, but not always.
+            setForwardReference(gcid, end > 0 ? line.substring(0, end) : line);
+            applyRule(matchedParseRule, parsed, line);
+        } else {
+            log(line);
+        }
     }
 
 

diff --git a/parser/src/main/java/com/microsoft/gctoolkit/parser/UnifiedGenerationalParser.java b/parser/src/main/java/com/microsoft/gctoolkit/parser/UnifiedGenerationalParser.java
@@ -170,11 +170,11 @@ private void youngHeader(GCLogTrace trace, String line) {
         if (pauseEvent != null)
             LOGGER.warning("Young pause event not recorded: " + pauseEvent.getGcID());
         if (diary.isCMS())
-            pauseEvent = new GenerationalForwardReference(ParNew, new Decorators(line), super.GCID_COUNTER.parse(line).getIntegerGroup(1));
+            pauseEvent = new GenerationalForwardReference(ParNew, new Decorators(line), extractGCID(line));
         else if (diary.isPSYoung())
-            pauseEvent = new GenerationalForwardReference(PSYoungGen, new Decorators(line), super.GCID_COUNTER.parse(line).getIntegerGroup(1));
+            pauseEvent = new GenerationalForwardReference(PSYoungGen, new Decorators(line), extractGCID(line));
         else if (diary.isSerialFull())
-            pauseEvent = new GenerationalForwardReference(DefNew, new Decorators(line), super.GCID_COUNTER.parse(line).getIntegerGroup(1));
+            pauseEvent = new GenerationalForwardReference(DefNew, new Decorators(line), extractGCID(line));
         else {
             LOGGER.warning("Unrecognized collection phase -> " + line);
             return;
@@ -261,7 +261,7 @@ private void tenuringAgeBreakout(GCLogTrace trace, String line) {
     private void initialMark(GCLogTrace trace, String line) {
         if (concurrentCyclePauseEvent != null)
             LOGGER.warning("Pause event not completely recorded: " + pauseEvent.getGcID());
-        concurrentCyclePauseEvent = new GenerationalForwardReference(InitialMark, new Decorators(line), GCID_COUNTER.parse(line).getIntegerGroup(1));
+        concurrentCyclePauseEvent = new GenerationalForwardReference(InitialMark, new Decorators(line), extractGCID(line));
         concurrentCyclePauseEvent.setStartTime(getClock());
     }
 
@@ -278,7 +278,7 @@ private void concurrentPhaseStart(GCLogTrace trace, String line) {
             LOGGER.warning("Unknown concurrent phase: " + line);
             return;
         }
-        concurrentEvent = new GenerationalForwardReference(gcType, new Decorators(line), GCID_COUNTER.parse(line).getIntegerGroup(1));
+        concurrentEvent = new GenerationalForwardReference(gcType, new Decorators(line), extractGCID(line));
         concurrentEvent.setStartTime(getClock());
         inConcurrentPhase = true;
     }
@@ -299,7 +299,7 @@ private void workerThreads(GCLogTrace trace, String line) {
     private void remark(GCLogTrace trace, String line) {
         if (concurrentCyclePauseEvent != null)
             LOGGER.warning("Pause event not recorded and is about to be lost: " + pauseEvent.getGcID());
-        concurrentCyclePauseEvent = new GenerationalForwardReference(Remark, new Decorators(line), GCID_COUNTER.parse(line).getIntegerGroup(1));
+        concurrentCyclePauseEvent = new GenerationalForwardReference(Remark, new Decorators(line), extractGCID(line));
         concurrentCyclePauseEvent.setStartTime(getClock());
     }
 
@@ -328,17 +328,17 @@ private void promotionFailed(GCLogTrace trace, String line) {
     private void fullGC(GCLogTrace trace, String line) {
         if (pauseEvent == null) {
             if (diary.isPSOldGen())
-                pauseEvent = new GenerationalForwardReference(PSFull, new Decorators(line), super.GCID_COUNTER.parse(line).getIntegerGroup(1));
+                pauseEvent = new GenerationalForwardReference(PSFull, new Decorators(line), extractGCID(line));
             else
-                pauseEvent = new GenerationalForwardReference(FullGC, new Decorators(line), super.GCID_COUNTER.parse(line).getIntegerGroup(1));
+                pauseEvent = new GenerationalForwardReference(FullGC, new Decorators(line), extractGCID(line));
             pauseEvent.setStartTime(getClock());
         } else if (pauseEvent.getGarbageCollectionType() == ParNew) {
             pauseEvent.convertToConcurrentModeFailure();
         } else if (pauseEvent.getGarbageCollectionType() == DefNew) {
             pauseEvent.convertToSerialFull();
         } else if (pauseEvent.getGarbageCollectionType() != ConcurrentModeFailure) {
             LOGGER.warning("Maybe Full Pause event not recorded: " + pauseEvent.getGcID()); //todo: difficult to know if this is a full or a CMF
-            pauseEvent = new GenerationalForwardReference(FullGC, new Decorators(line), super.GCID_COUNTER.parse(line).getIntegerGroup(1));
+            pauseEvent = new GenerationalForwardReference(FullGC, new Decorators(line), extractGCID(line));
             pauseEvent.setStartTime(getClock());
         }
         pauseEvent.setGCCause(trace.gcCause(1, 0));
@@ -384,10 +384,9 @@ private void jvmExit(GCLogTrace trace, String line) {
     private ArrayList<GenerationalGCPauseEvent> cache = new ArrayList<>();
 
     private void cpuBreakout(GCLogTrace trace, String line) {
-        GCLogTrace gcidTrace = GCID_COUNTER.parse(line);
-        if (gcidTrace != null) {
+        int gcid = extractGCID(line);
+        if (gcid != -1) {
             CPUSummary cpuSummary = new CPUSummary(trace.getDoubleGroup(1), trace.getDoubleGroup(2), trace.getDoubleGroup(3));
-            int gcid = gcidTrace.getIntegerGroup(1);
             // There are 3 cases to consider.
             // - pause event outside of a concurrent cycle
             // - pause event that is part of the concurrent cycle

diff --git a/parser/src/test/java/com/microsoft/gctoolkit/parser/GCLogParserTest.java b/parser/src/test/java/com/microsoft/gctoolkit/parser/GCLogParserTest.java
@@ -0,0 +1,32 @@
+package com.microsoft.gctoolkit.parser;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class GCLogParserTest {
+    @Test
+    void extractPackedGCCycleIdAndTextualLength() {
+        long packed = GCLogParser.extractGCCycleIdAndTextualLength("[2025-10-21T16:44:29.311+0200][3645.640s] GC(35) Pause Young (Allocation Failure)");
+        assertEquals(35, GCLogParser.extractGCCycleId(packed));
+        assertEquals(48, GCLogParser.extractGCCycleIdTextualLength(packed));
+    }
+
+    @Test
+    void extractGCID() {
+        assertEquals(35, GCLogParser.extractGCID("[2025-10-21T16:44:29.311+0200][3645.640s] GC(35) Pause Young (Allocation Failure)"));
+    }
+
+    @Test
+    void extractPackedGCCycleIdAndTextualLength_malformed() {
+        long packed = GCLogParser.extractGCCycleIdAndTextualLength("[2025-10-21T16:44:29.311+0200][3645.640s] GC(3");
+        assertEquals(-1 , packed);
+        assertEquals(-1, GCLogParser.extractGCCycleId(packed));
+        assertEquals(0, GCLogParser.extractGCCycleIdTextualLength(packed));
+    }
+
+    @Test
+    void extractGCID_malformed() {
+        assertEquals(-1, GCLogParser.extractGCID("[2025-10-21T16:44:29.311+0200][3645.640s] GC(3"));
+    }
+}