7903455: JMH: Add "mempool" profiler

Reviewed-by: shade

jmh-core/src/main/java/org/openjdk/jmh/profile/MemPoolProfiler.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2005, 2023, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package org.openjdk.jmh.profile;
+
+import org.openjdk.jmh.infra.BenchmarkParams;
+import org.openjdk.jmh.infra.IterationParams;
+import org.openjdk.jmh.results.*;
+
+import java.lang.management.MemoryPoolMXBean;
+import java.lang.management.ManagementFactory;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+public class MemPoolProfiler implements InternalProfiler {
+    static final double BYTES_PER_KIB = 1024D;
+
+    @Override
+    public String getDescription() {
+        return "Memory pool/footprint profiling via standard MBeans";
+    }
+
+    @Override
+    public void beforeIteration(BenchmarkParams benchmarkParams, IterationParams iterationParams) {
+        for (MemoryPoolMXBean b : ManagementFactory.getMemoryPoolMXBeans()) {
+            b.resetPeakUsage();
+        }
+    }
+
+    @Override
+    public Collection<? extends Result> afterIteration(BenchmarkParams benchmarkParams, IterationParams iterationParams, IterationResult result) {
+        List<Result> results = new ArrayList<>();
+
+        long sumCodeHeap = 0L;
+        long sum = 0L;
+        for (MemoryPoolMXBean bean : ManagementFactory.getMemoryPoolMXBeans()) {
+            long used = bean.getPeakUsage().getUsed();
+            if (bean.getName().contains("CodeHeap")) {
+                sumCodeHeap += used;
+            }
+            sum += used;
+
+            results.add(new ScalarResult(Defaults.PREFIX + "mempool." + bean.getName() + ".used", used / BYTES_PER_KIB, "KiB", AggregationPolicy.MAX));
+        }
+
+        results.add(new ScalarResult(Defaults.PREFIX + "mempool.total.codeheap.used", sumCodeHeap / BYTES_PER_KIB, "KiB", AggregationPolicy.MAX));
+        results.add(new ScalarResult(Defaults.PREFIX + "mempool.total.used", sum / BYTES_PER_KIB, "KiB", AggregationPolicy.MAX));
+        return results;
+    }
+}

jmh-core/src/main/java/org/openjdk/jmh/profile/ProfilerFactory.java

@@ -173,6 +173,7 @@ public static void listProfilers(PrintStream out) {
         BUILT_IN.put("perf",     LinuxPerfProfiler.class);
         BUILT_IN.put("perfnorm", LinuxPerfNormProfiler.class);
         BUILT_IN.put("perfasm",  LinuxPerfAsmProfiler.class);
+        BUILT_IN.put("mempool",  MemPoolProfiler.class);
         BUILT_IN.put("xperfasm", WinPerfAsmProfiler.class);
         BUILT_IN.put("dtraceasm", DTraceAsmProfiler.class);
         BUILT_IN.put("pauses",   PausesProfiler.class);