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author | Shixiong Zhu <shixiong@databricks.com> | 2015-12-01 09:45:55 -0800 |
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committer | Shixiong Zhu <shixiong@databricks.com> | 2015-12-01 09:45:55 -0800 |
commit | 1401166576c7018c5f9c31e0a6703d5fb16ea339 (patch) | |
tree | 3cdfa3ce9c6cd6eefe56ea1a5491b45f4392556f | |
parent | c87531b765f8934a9a6c0f673617e0abfa5e5f0e (diff) | |
download | spark-1401166576c7018c5f9c31e0a6703d5fb16ea339.tar.gz spark-1401166576c7018c5f9c31e0a6703d5fb16ea339.tar.bz2 spark-1401166576c7018c5f9c31e0a6703d5fb16ea339.zip |
[SPARK-12060][CORE] Avoid memory copy in JavaSerializerInstance.serialize
`JavaSerializerInstance.serialize` uses `ByteArrayOutputStream.toByteArray` to get the serialized data. `ByteArrayOutputStream.toByteArray` needs to copy the content in the internal array to a new array. However, since the array will be converted to `ByteBuffer` at once, we can avoid the memory copy.
This PR added `ByteBufferOutputStream` to access the protected `buf` and convert it to a `ByteBuffer` directly.
Author: Shixiong Zhu <shixiong@databricks.com>
Closes #10051 from zsxwing/SPARK-12060.
-rw-r--r-- | core/src/main/scala/org/apache/spark/serializer/JavaSerializer.scala | 7 | ||||
-rw-r--r-- | core/src/main/scala/org/apache/spark/util/ByteBufferOutputStream.scala | 31 |
2 files changed, 34 insertions, 4 deletions
diff --git a/core/src/main/scala/org/apache/spark/serializer/JavaSerializer.scala b/core/src/main/scala/org/apache/spark/serializer/JavaSerializer.scala index b463a71d5b..ea718a0edb 100644 --- a/core/src/main/scala/org/apache/spark/serializer/JavaSerializer.scala +++ b/core/src/main/scala/org/apache/spark/serializer/JavaSerializer.scala @@ -24,8 +24,7 @@ import scala.reflect.ClassTag import org.apache.spark.SparkConf import org.apache.spark.annotation.DeveloperApi -import org.apache.spark.util.ByteBufferInputStream -import org.apache.spark.util.Utils +import org.apache.spark.util.{ByteBufferInputStream, ByteBufferOutputStream, Utils} private[spark] class JavaSerializationStream( out: OutputStream, counterReset: Int, extraDebugInfo: Boolean) @@ -96,11 +95,11 @@ private[spark] class JavaSerializerInstance( extends SerializerInstance { override def serialize[T: ClassTag](t: T): ByteBuffer = { - val bos = new ByteArrayOutputStream() + val bos = new ByteBufferOutputStream() val out = serializeStream(bos) out.writeObject(t) out.close() - ByteBuffer.wrap(bos.toByteArray) + bos.toByteBuffer } override def deserialize[T: ClassTag](bytes: ByteBuffer): T = { diff --git a/core/src/main/scala/org/apache/spark/util/ByteBufferOutputStream.scala b/core/src/main/scala/org/apache/spark/util/ByteBufferOutputStream.scala new file mode 100644 index 0000000000..92e45224db --- /dev/null +++ b/core/src/main/scala/org/apache/spark/util/ByteBufferOutputStream.scala @@ -0,0 +1,31 @@ +/* + * 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.spark.util + +import java.io.ByteArrayOutputStream +import java.nio.ByteBuffer + +/** + * Provide a zero-copy way to convert data in ByteArrayOutputStream to ByteBuffer + */ +private[spark] class ByteBufferOutputStream extends ByteArrayOutputStream { + + def toByteBuffer: ByteBuffer = { + return ByteBuffer.wrap(buf, 0, count) + } +} |