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Posted to commits@commons.apache.org by tv...@apache.org on 2014/01/06 18:40:00 UTC
svn commit: r1555939 - in /commons/proper/jcs/trunk/src: changes/changes.xml
java/org/apache/commons/jcs/auxiliary/disk/block/BlockDisk.java
Author: tv
Date: Mon Jan 6 17:40:00 2014
New Revision: 1555939
URL: http://svn.apache.org/r1555939
Log:
JCS-109: Improve performance of BlockDisk.write(Serializable)
Modified:
commons/proper/jcs/trunk/src/changes/changes.xml
commons/proper/jcs/trunk/src/java/org/apache/commons/jcs/auxiliary/disk/block/BlockDisk.java
Modified: commons/proper/jcs/trunk/src/changes/changes.xml
URL: http://svn.apache.org/viewvc/commons/proper/jcs/trunk/src/changes/changes.xml?rev=1555939&r1=1555938&r2=1555939&view=diff
==============================================================================
--- commons/proper/jcs/trunk/src/changes/changes.xml (original)
+++ commons/proper/jcs/trunk/src/changes/changes.xml Mon Jan 6 17:40:00 2014
@@ -20,6 +20,9 @@
</properties>
<body>
<release version="2.0" date="unreleased" description="JDK 1.5 based major release">
+ <action dev="tv" type="update" issue="JCS-109" due-to="Xiong LIU">
+ Improve performance of BlockDisk.write(Serializable)
+ </action>
<action dev="tv" type="fix" issue="JCS-102" due-to="Robert Clark">
Reworked the interfaces to make the group cache typesafe
</action>
Modified: commons/proper/jcs/trunk/src/java/org/apache/commons/jcs/auxiliary/disk/block/BlockDisk.java
URL: http://svn.apache.org/viewvc/commons/proper/jcs/trunk/src/java/org/apache/commons/jcs/auxiliary/disk/block/BlockDisk.java?rev=1555939&r1=1555938&r2=1555939&view=diff
==============================================================================
--- commons/proper/jcs/trunk/src/java/org/apache/commons/jcs/auxiliary/disk/block/BlockDisk.java (original)
+++ commons/proper/jcs/trunk/src/java/org/apache/commons/jcs/auxiliary/disk/block/BlockDisk.java Mon Jan 6 17:40:00 2014
@@ -48,7 +48,7 @@ public class BlockDisk
private static final Log log = LogFactory.getLog( BlockDisk.class );
/** The size of the header that indicates the amount of data stored in an occupied block. */
- public static final byte HEADER_SIZE_BYTES = 4;
+ public static final byte HEADER_SIZE_BYTES = 4;
// N.B. 4 bytes is the size used for ByteBuffer.putInt(int value) and ByteBuffer.getInt()
/** defaults to 4kb */
@@ -132,6 +132,31 @@ public class BlockDisk
}
/**
+ * Allocate a given number of blocks from the available set
+ *
+ * @param numBlocksNeeded
+ * @return an array of allocated blocks
+ */
+ private int[] allocateBlocks(int numBlocksNeeded)
+ {
+ assert numBlocksNeeded >= 1;
+
+ int[] blocks = new int[numBlocksNeeded];
+ // get them from the empty list or take the next one
+ for (int i = 0; i < numBlocksNeeded; i++)
+ {
+ Integer emptyBlock = emptyBlocks.takeFirst();
+ if (emptyBlock == null)
+ {
+ emptyBlock = numberOfBlocks.getAndIncrement();
+ }
+ blocks[i] = emptyBlock;
+ }
+
+ return blocks;
+ }
+
+ /**
* This writes an object to disk and returns the blocks it was stored in.
* <p>
* The program flow is as follows:
@@ -152,7 +177,7 @@ public class BlockDisk
throws IOException
{
// serialize the object
- byte[] data = elementSerializer.serialize( object );
+ byte[] data = elementSerializer.serialize(object);
if ( log.isDebugEnabled() )
{
@@ -163,38 +188,43 @@ public class BlockDisk
this.putCount.incrementAndGet();
// figure out how many blocks we need.
- int numBlocksNeeded = calculateTheNumberOfBlocksNeeded( data );
+ int numBlocksNeeded = calculateTheNumberOfBlocksNeeded(data);
+
if ( log.isDebugEnabled() )
{
log.debug( "numBlocksNeeded = " + numBlocksNeeded );
}
- int[] blocks = new int[numBlocksNeeded];
+ // allocate blocks
+ int[] blocks = allocateBlocks(numBlocksNeeded);
- // get them from the empty list or take the next one
- for ( int i = 0; i < numBlocksNeeded; i++ )
+ int offset = 0;
+ final int maxChunkSize = blockSizeBytes - HEADER_SIZE_BYTES;
+ ByteBuffer headerBuffer = ByteBuffer.allocate(HEADER_SIZE_BYTES);
+
+ for (int i = 0; i < numBlocksNeeded; i++)
{
- Integer emptyBlock = emptyBlocks.takeFirst();
- if ( emptyBlock != null )
- {
- blocks[i] = emptyBlock.intValue();
- }
- else
- {
- blocks[i] = this.numberOfBlocks.getAndIncrement();
- }
- }
+ headerBuffer.clear();
+ int length = Math.min(maxChunkSize, data.length - offset);
+ headerBuffer.putInt(length);
- // get the individual sub arrays.
- byte[][] chunks = getBlockChunks( data, numBlocksNeeded );
+ ByteBuffer dataBuffer = ByteBuffer.wrap(data, offset, length);
- // write the blocks
- for ( int i = 0; i < numBlocksNeeded; i++ )
- {
- int position = calculateByteOffsetForBlock( blocks[i] );
- write( position, chunks[i] );
+ long position = calculateByteOffsetForBlock(blocks[i]);
+ // write the header
+ headerBuffer.flip();
+ int written = fc.write(headerBuffer, position);
+ assert written == HEADER_SIZE_BYTES;
+
+ //write the data
+ written = fc.write(dataBuffer, position + HEADER_SIZE_BYTES);
+ assert written == length;
+
+ offset += length;
}
+ fc.force(false);
+
return blocks;
}
@@ -236,27 +266,6 @@ public class BlockDisk
}
/**
- * Writes the given byte array to the Disk at the specified position.
- * <p>
- * @param position
- * @param data
- * @return true if we wrote successfully
- * @throws IOException
- */
- private boolean write( long position, byte[] data )
- throws IOException
- {
- ByteBuffer buffer = ByteBuffer.allocate(HEADER_SIZE_BYTES + data.length);
- buffer.putInt(data.length);
- buffer.put(data);
- buffer.flip();
- int written = fc.write(buffer, position);
- fc.force(true);
-
- return written == data.length + HEADER_SIZE_BYTES;
- }
-
- /**
* Reads an object that is located in the specified blocks.
* <p>
* @param blockNumbers