From 545f135f12f90c6ef5c5a1740a5c332ff5ebbecf Mon Sep 17 00:00:00 2001
From: liyafan82 <fan_li_ya@foxmail.com>
Date: Thu, 27 Jun 2019 12:44:23 +0800
Subject: [PATCH] [ARROW-5752][Java] Improve the performance of
 ArrowBuf#setZero

---
 .../main/java/io/netty/buffer/ArrowBuf.java   | 29 +------
 .../io/netty/buffer/ArrowBufBenchmarks.java   | 86 +++++++++++++++++++
 2 files changed, 89 insertions(+), 26 deletions(-)
 create mode 100644 java/performance/src/test/java/io/netty/buffer/ArrowBufBenchmarks.java

diff --git a/java/memory/src/main/java/io/netty/buffer/ArrowBuf.java b/java/memory/src/main/java/io/netty/buffer/ArrowBuf.java
index c3b34b6fc5c5..c7502b47778f 100644
--- a/java/memory/src/main/java/io/netty/buffer/ArrowBuf.java
+++ b/java/memory/src/main/java/io/netty/buffer/ArrowBuf.java
@@ -1158,34 +1158,11 @@ public ArrowBuf writerIndex(int writerIndex) {
    * @return this ArrowBuf
    */
   public ArrowBuf setZero(int index, int length) {
-    if (length == 0) {
-      return this;
-    } else {
+    if (length != 0) {
       this.checkIndex(index, length);
-      int nLong = length >>> 3;
-      int nBytes = length & 7;
-      int i;
-      for (i = nLong; i > 0; --i) {
-        setLong(index, 0L);
-        index += 8;
-      }
-      if (nBytes == 4) {
-        setInt(index, 0);
-      } else if (nBytes < 4) {
-        for (i = nBytes; i > 0; --i) {
-          setByte(index, 0);
-          ++index;
-        }
-      } else {
-        setInt(index, 0);
-        index += 4;
-        for (i = nBytes - 4; i > 0; --i) {
-          setByte(index, 0);
-          ++index;
-        }
-      }
-      return this;
+      PlatformDependent.setMemory(this.addr + index, length, (byte) 0);
     }
+    return this;
   }
 
   /**
diff --git a/java/performance/src/test/java/io/netty/buffer/ArrowBufBenchmarks.java b/java/performance/src/test/java/io/netty/buffer/ArrowBufBenchmarks.java
new file mode 100644
index 000000000000..dc43070c7ffa
--- /dev/null
+++ b/java/performance/src/test/java/io/netty/buffer/ArrowBufBenchmarks.java
@@ -0,0 +1,86 @@
+/*
+ * 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 io.netty.buffer;
+
+import java.util.concurrent.TimeUnit;
+
+import org.apache.arrow.memory.BufferAllocator;
+import org.apache.arrow.memory.RootAllocator;
+import org.junit.Test;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+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.TearDown;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.RunnerException;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+/**
+ * Benchmarks for {@link ArrowBuf}.
+ */
+@State(Scope.Benchmark)
+public class ArrowBufBenchmarks {
+
+  private static final int BUFFER_CAPACITY = 1024 * 1024;
+
+  private static final int ALLOCATOR_CAPACITY = 1024 * 1024;
+
+  private BufferAllocator allocator;
+
+  private ArrowBuf buffer;
+
+  /**
+   * Setup benchmarks.
+   */
+  @Setup
+  public void prepare() {
+    allocator = new RootAllocator(ALLOCATOR_CAPACITY);
+    buffer = allocator.buffer(BUFFER_CAPACITY);
+  }
+
+  /**
+   * Tear down benchmarks.
+   */
+  @TearDown
+  public void tearDown() {
+    buffer.close();
+    allocator.close();
+  }
+
+  @Benchmark
+  @BenchmarkMode(Mode.AverageTime)
+  @OutputTimeUnit(TimeUnit.NANOSECONDS)
+  public void setZero() {
+    buffer.setZero(0, BUFFER_CAPACITY);
+  }
+
+  @Test
+  public void evaluate() throws RunnerException {
+    Options opt = new OptionsBuilder()
+            .include(ArrowBufBenchmarks.class.getSimpleName())
+            .forks(1)
+            .build();
+
+    new Runner(opt).run();
+  }
+}