Virtual threads metrics

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/jvm/JvmVirtualThreadEventMetrics.java

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+/*
+ * Copyright 2024 VMware, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.micrometer.core.instrument.binder.jvm;
+
+import io.micrometer.core.instrument.Counter;
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Tag;
+import io.micrometer.core.instrument.Timer;
+import io.micrometer.core.instrument.binder.MeterBinder;
+import jdk.jfr.consumer.RecordingStream;
+
+import static java.util.Collections.emptyList;
+
+public class JvmVirtualThreadEventMetrics implements MeterBinder, AutoCloseable {
+
+    private final Iterable<Tag> tags;
+
+    private final RecordingStream recordingStream;
+
+    public JvmVirtualThreadEventMetrics() {
+        this(emptyList());
+    }
+
+    public JvmVirtualThreadEventMetrics(Iterable<Tag> tags) {
+        this.tags = tags;
+        this.recordingStream = new RecordingStream();
+
+        recordingStream.enable("jdk.VirtualThreadPinnedEvent");
+        recordingStream.enable("jdk.VirtualThreadSubmitFailedEvent");
+    }
+
+    @Override
+    public void bindTo(MeterRegistry registry) {
+        final Timer pinnedTimer =
+            Timer.builder("jvm.virtual.thread.pinned")
+                .tags(tags)
+                .description("The duration of virtual threads that were pinned to a physical thread")
+                .register(registry);
+
+        final Counter submitFailedCounter =
+            Counter.builder("jvm.virtual.thread.submit.failed")
+                .tags(tags)
+                .description("The number of virtual thread submissions that failed")
+                .register(registry);
+
+        recordingStream.onEvent("jdk.VirtualThreadPinnedEvent", event ->
+            pinnedTimer.record(event.getDuration()));
+
+        recordingStream.onEvent("jdk.VirtualThreadSubmitFailedEvent",
+            event -> submitFailedCounter.increment());
+    }
+
+    @Override
+    public void close() throws Exception {
+        recordingStream.close();
+    }
+}