Add Log4j2 benchmark tool

- Configurable thread count, duration, message size
- Multiple logging configurations: sync-immediate, sync-buffered
- AsyncLogger variants: 1k, 4k, 10k, 1m ring buffer sizes
- AsyncAppender variants: 1k, 4k, 10k, 1m buffer sizes
- Subprocess isolation for proper async logger initialization
- Cache dropping between tests for accurate benchmarks
- CSV output support

1 files changed, 51 insertions, 0 deletions

diff --git a/src/main/java/bench/LogWorker.java b/src/main/java/bench/LogWorker.java
new file mode 100644
index 0000000..5a9edfc
--- /dev/null
+++ b/src/main/java/bench/LogWorker.java
@@ -0,0 +1,51 @@
+package bench;
+
+import org.apache.logging.log4j.Logger;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+
+public class LogWorker implements Runnable {
+    private final Logger logger;
+    private final String message;
+    private final CountDownLatch startLatch;
+    private final AtomicBoolean running;
+    private final AtomicLong eventCounter;
+    private final AtomicLong targetEvents;
+    private final BenchConfig.Mode mode;
+
+    public LogWorker(Logger logger, String message, CountDownLatch startLatch,
+                     AtomicBoolean running, AtomicLong eventCounter,
+                     AtomicLong targetEvents, BenchConfig.Mode mode) {
+        this.logger = logger;
+        this.message = message;
+        this.startLatch = startLatch;
+        this.running = running;
+        this.eventCounter = eventCounter;
+        this.targetEvents = targetEvents;
+        this.mode = mode;
+    }
+
+    @Override
+    public void run() {
+        try {
+            startLatch.await();
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            return;
+        }
+
+        if (mode == BenchConfig.Mode.DURATION) {
+            while (running.get()) {
+                logger.info(message);
+                eventCounter.incrementAndGet();
+            }
+        } else {
+            while (running.get() && eventCounter.get() < targetEvents.get()) {
+                logger.info(message);
+                eventCounter.incrementAndGet();
+            }
+        }
+    }
+}