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From 0f9ef0bc57aa0e7d8457b645374be74d510ea7ae Mon Sep 17 00:00:00 2001
Date: Thu, 18 Mar 2021 12:35:14 +0000
Subject: [PATCH 2/4] 8254078: DataOutputStream is very slow post disabling
---
.../classes/java/io/DataInputStream.java | 7 +-
.../classes/java/io/DataOutputStream.java | 24 ++--
.../bench/java/io/DataOutputStreamTest.java | 124 ++++++++++++++++++
3 files changed, 144 insertions(+), 11 deletions(-)
create mode 100644 test/micro/org/openjdk/bench/java/io/DataOutputStreamTest.java
diff --git a/src/java.base/share/classes/java/io/DataInputStream.java b/src/java.base/share/classes/java/io/DataInputStream.java
index f92c4f91b..114857691 100644
--- a/src/java.base/share/classes/java/io/DataInputStream.java
+++ b/src/java.base/share/classes/java/io/DataInputStream.java
@@ -31,9 +31,10 @@ package java.io;
* way. An application uses a data output stream to write data that
* can later be read by a data input stream.
* <p>
- * DataInputStream is not necessarily safe for multithreaded access.
- * Thread safety is optional and is the responsibility of users of
- * methods in this class.
+ * A DataInputStream is not safe for use by multiple concurrent
+ * threads. If a DataInputStream is to be used by more than one
+ * thread then access to the data input stream should be controlled
+ * by appropriate synchronization.
*
* @author Arthur van Hoff
* @see java.io.DataOutputStream
diff --git a/src/java.base/share/classes/java/io/DataOutputStream.java b/src/java.base/share/classes/java/io/DataOutputStream.java
index 392abba92..7c0962442 100644
--- a/src/java.base/share/classes/java/io/DataOutputStream.java
+++ b/src/java.base/share/classes/java/io/DataOutputStream.java
@@ -29,6 +29,11 @@ package java.io;
* A data output stream lets an application write primitive Java data
* types to an output stream in a portable way. An application can
* then use a data input stream to read the data back in.
+ * <p>
+ * A DataOutputStream is not safe for use by multiple concurrent
+ * threads. If a DataOutputStream is to be used by more than one
+ * thread then access to the data output stream should be controlled
+ * by appropriate synchronization.
*
* @author unascribed
* @see java.io.DataInputStream
@@ -164,8 +169,9 @@ class DataOutputStream extends FilterOutputStream implements DataOutput {
* @see java.io.FilterOutputStream#out
*/
public final void writeShort(int v) throws IOException {
- out.write((v >>> 8) & 0xFF);
- out.write((v >>> 0) & 0xFF);
+ writeBuffer[0] = (byte)(v >>> 8);
+ writeBuffer[1] = (byte)(v >>> 0);
+ out.write(writeBuffer, 0, 2);
incCount(2);
}
@@ -179,8 +185,9 @@ class DataOutputStream extends FilterOutputStream implements DataOutput {
* @see java.io.FilterOutputStream#out
*/
public final void writeChar(int v) throws IOException {
- out.write((v >>> 8) & 0xFF);
- out.write((v >>> 0) & 0xFF);
+ writeBuffer[0] = (byte)(v >>> 8);
+ writeBuffer[1] = (byte)(v >>> 0);
+ out.write(writeBuffer, 0, 2);
incCount(2);
}
@@ -194,10 +201,11 @@ class DataOutputStream extends FilterOutputStream implements DataOutput {
* @see java.io.FilterOutputStream#out
*/
public final void writeInt(int v) throws IOException {
- out.write((v >>> 24) & 0xFF);
- out.write((v >>> 16) & 0xFF);
- out.write((v >>> 8) & 0xFF);
- out.write((v >>> 0) & 0xFF);
+ writeBuffer[0] = (byte)(v >>> 24);
+ writeBuffer[1] = (byte)(v >>> 16);
+ writeBuffer[2] = (byte)(v >>> 8);
+ writeBuffer[3] = (byte)(v >>> 0);
+ out.write(writeBuffer, 0, 4);
incCount(4);
}
diff --git a/test/micro/org/openjdk/bench/java/io/DataOutputStreamTest.java b/test/micro/org/openjdk/bench/java/io/DataOutputStreamTest.java
new file mode 100644
index 000000000..2f573e6dd
--- /dev/null
+++ b/test/micro/org/openjdk/bench/java/io/DataOutputStreamTest.java
@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2020, Red Hat Inc. 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.
+ *
+ * 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.bench.java.io;
+
+import org.openjdk.jmh.annotations.*;
+
+import java.io.*;
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MICROSECONDS)
+@Fork(value = 1, warmups = 0)
+@Measurement(iterations = 6, time = 1)
+@Warmup(iterations=2, time = 2)
+@State(Scope.Benchmark)
+public class DataOutputStreamTest {
+
+ public enum BasicType {CHAR, SHORT, INT, STRING}
+ @Param({"CHAR", "SHORT", "INT", /* "STRING"*/}) BasicType basicType;
+
+ @Param({"4096"}) int size;
+
+ final ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(size);
+ File f;
+ String outputString;
+ FileOutputStream fileOutputStream;
+ DataOutput bufferedFileStream, rawFileStream, byteArrayStream;
+
+ @Setup(Level.Trial)
+ public void setup() throws Exception {
+ f = File.createTempFile("DataOutputStreamTest","out");
+ fileOutputStream = new FileOutputStream(f);
+ byteArrayStream = new DataOutputStream(byteArrayOutputStream);
+ rawFileStream = new DataOutputStream(fileOutputStream);
+ bufferedFileStream = new DataOutputStream(new BufferedOutputStream(fileOutputStream));
+ outputString = new String(new byte[size]);
+ }
+
+ public void writeChars(DataOutput dataOutput)
+ throws Exception {
+ for (int i = 0; i < size; i += 2) {
+ dataOutput.writeChar(i);
+ }
+ }
+
+ public void writeShorts(DataOutput dataOutput)
+ throws Exception {
+ for (int i = 0; i < size; i += 2) {
+ dataOutput.writeShort(i);
+ }
+ }
+
+ public void writeInts(DataOutput dataOutput)
+ throws Exception {
+ for (int i = 0; i < size; i += 4) {
+ dataOutput.writeInt(i);
+ }
+ }
+
+ public void writeString(DataOutput dataOutput)
+ throws Exception {
+ dataOutput.writeChars(outputString);
+ }
+
+ public void write(DataOutput dataOutput)
+ throws Exception {
+ switch (basicType) {
+ case CHAR:
+ writeChars(dataOutput);
+ break;
+ case SHORT:
+ writeShorts(dataOutput);
+ break;
+ case INT:
+ writeInts(dataOutput);
+ break;
+ case STRING:
+ writeString(dataOutput);
+ break;
+ }
+ }
+
+ @Benchmark
+ public void dataOutputStreamOverByteArray() throws Exception {
+ byteArrayOutputStream.reset();
+ write(byteArrayStream);
+ byteArrayOutputStream.flush();
+ }
+
+ @Benchmark
+ public void dataOutputStreamOverRawFileStream() throws Exception {
+ fileOutputStream.getChannel().position(0);
+ write(rawFileStream);
+ fileOutputStream.flush();
+ }
+
+ @Benchmark
+ public void dataOutputStreamOverBufferedFileStream() throws Exception{
+ fileOutputStream.getChannel().position(0);
+ write(bufferedFileStream);
+ fileOutputStream.flush();
+ }
+}
--
2.19.0
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