Add JMH benchmark.

lucene/benchmark-jmh/src/java/org/apache/lucene/benchmark/jmh/AdvanceBenchmark.java

@@ -0,0 +1,180 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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
+ *
+ *     http://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 org.apache.lucene.benchmark.jmh;
+
+import java.util.Arrays;
+import java.util.Random;
+import java.util.concurrent.TimeUnit;
+import org.apache.lucene.search.DocIdSetIterator;
+import org.apache.lucene.util.VectorUtil;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.CompilerControl;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Level;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+
+@BenchmarkMode(Mode.Throughput)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@State(Scope.Benchmark)
+@Warmup(iterations = 5, time = 1)
+@Measurement(iterations = 5, time = 1)
+@Fork(
+    value = 3,
+    jvmArgsAppend = {
+      "-Xmx1g",
+      "-Xms1g",
+      "-XX:+AlwaysPreTouch",
+      "--add-modules",
+      "jdk.incubator.vector"
+    })
+public class AdvanceBenchmark {
+
+  private final long[] values = new long[129];
+  private final int[] startIndexes = new int[1_000];
+  private final long[] targets = new long[startIndexes.length];
+
+  @Setup(Level.Trial)
+  public void setup() throws Exception {
+    for (int i = 0; i < 128; ++i) {
+      values[i] = i;
+    }
+    values[128] = DocIdSetIterator.NO_MORE_DOCS;
+    Random r = new Random(0);
+    for (int i = 0; i < startIndexes.length; ++i) {
+      startIndexes[i] = r.nextInt(64);
+      targets[i] = startIndexes[i] + 1 + r.nextInt(1 << r.nextInt(7));
+    }
+  }
+
+  @Benchmark
+  public void binarySearch() {
+    for (int i = 0; i < startIndexes.length; ++i) {
+      binarySearch(values, targets[i], startIndexes[i]);
+    }
+  }
+
+  @CompilerControl(CompilerControl.Mode.DONT_INLINE)
+  private static int binarySearch(long[] values, long target, int startIndex) {
+    // Standard binary search
+    int i = Arrays.binarySearch(values, startIndex, values.length, target);
+    if (i < 0) {
+      i = -1 - i;
+    }
+    return i;
+  }
+
+  @Benchmark
+  public void inlinedBranchlessBinarySearch() {
+    for (int i = 0; i < targets.length; ++i) {
+      inlinedBranchlessBinarySearch(values, targets[i]);
+    }
+  }
+
+  @CompilerControl(CompilerControl.Mode.DONT_INLINE)
+  private static int inlinedBranchlessBinarySearch(long[] values, long target) {
+    // This compiles to cmov instructions.
+    int start = 0;
+
+    if (values[63] < target) {
+      start += 64;
+    }
+    if (values[start + 31] < target) {
+      start += 32;
+    }
+    if (values[start + 15] < target) {
+      start += 16;
+    }
+    if (values[start + 7] < target) {
+      start += 8;
+    }
+    if (values[start + 3] < target) {
+      start += 4;
+    }
+    if (values[start + 1] < target) {
+      start += 2;
+    }
+    if (values[start] < target) {
+      start += 1;
+    }
+
+    return start;
+  }
+
+  @Benchmark
+  public void linearSearch() {
+    for (int i = 0; i < startIndexes.length; ++i) {
+      linearSearch(values, targets[i], startIndexes[i]);
+    }
+  }
+
+  @CompilerControl(CompilerControl.Mode.DONT_INLINE)
+  private static int linearSearch(long[] values, long target, int startIndex) {
+    // Naive linear search.
+    for (int i = startIndex; i < values.length; ++i) {
+      if (values[i] >= target) {
+        return i;
+      }
+    }
+    return values.length;
+  }
+
+  @Benchmark
+  public void vectorUtilSearch() {
+    for (int i = 0; i < startIndexes.length; ++i) {
+      VectorUtil.findFirstGreater(values, 128, targets[i], startIndexes[i]);
+    }
+  }
+
+  @CompilerControl(CompilerControl.Mode.DONT_INLINE)
+  private static int vectorUtilSearch(long[] values, long target, int startIndex) {
+    return VectorUtil.findFirstGreater(values, 128, target, startIndex);
+  }
+
+  private static void assertEquals(int expected, int actual) {
+    if (expected != actual) {
+      throw new AssertionError("Expected: " + expected + ", got " + actual);
+    }
+  }
+
+  public static void main(String[] args) {
+    // For testing purposes
+    long[] values = new long[129];
+    for (int i = 0; i < 128; ++i) {
+      values[i] = i;
+    }
+    values[128] = DocIdSetIterator.NO_MORE_DOCS;
+    for (int start = 0; start < 128; ++start) {
+      for (int targetIndex = start; targetIndex < 128; ++targetIndex) {
+        int actualIndex = binarySearch(values, values[targetIndex], start);
+        assertEquals(targetIndex, actualIndex);
+        actualIndex = inlinedBranchlessBinarySearch(values, values[targetIndex]);
+        assertEquals(targetIndex, actualIndex);
+        actualIndex = linearSearch(values, values[targetIndex], start);
+        assertEquals(targetIndex, actualIndex);
+        actualIndex = vectorUtilSearch(values, values[targetIndex], start);
+        assertEquals(targetIndex, actualIndex);
+      }
+    }
+  }
+}