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Posted to commits@hbase.apache.org by li...@apache.org on 2014/04/02 22:49:20 UTC
svn commit: r1584166 - in /hbase/branches/0.89-fb/src:
main/java/org/apache/hadoop/hbase/
main/java/org/apache/hadoop/hbase/regionserver/
main/java/org/apache/hadoop/hbase/util/
test/java/org/apache/hadoop/hbase/util/
Author: liyin
Date: Wed Apr 2 20:49:19 2014
New Revision: 1584166
URL: http://svn.apache.org/r1584166
Log:
[HBASE-10759] Testing the performance of Guava comparator.
Author: manukranthk
Summary: Adding guava comparator into the Bytes.compareTo function which is very fundamental to HBase compare functions and comparators.
Test Plan: Added a unit test which suggests that the guava comparator give slight improvement.
Reviewers: rshroff, liyintang, daviddeng
Reviewed By: daviddeng
CC: hbase-eng@, platform-diffs@lists
Differential Revision: https://phabricator.fb.com/D785376
Task ID: 2268161
Modified:
hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/HConstants.java
hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/util/Bytes.java
hbase/branches/0.89-fb/src/test/java/org/apache/hadoop/hbase/util/TestBytes.java
Modified: hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/HConstants.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/HConstants.java?rev=1584166&r1=1584165&r2=1584166&view=diff
==============================================================================
--- hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/HConstants.java (original)
+++ hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/HConstants.java Wed Apr 2 20:49:19 2014
@@ -1062,6 +1062,10 @@ public final class HConstants {
"hbase.client.use.conf.from.server";
public static final boolean DEFAULT_USE_CONF_FROM_SERVER = true;
+ public static final String USE_GUAVA_BYTES_COMPARISION =
+ "hbase.regionserver.use.guava.bytes.comparision";
+ public static boolean DEFAULT_USE_GUAVA_BYTES_COMPARISION = false;
+
private HConstants() {
// Can't be instantiated with this constructor.
}
Modified: hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java?rev=1584166&r1=1584165&r2=1584166&view=diff
==============================================================================
--- hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java (original)
+++ hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java Wed Apr 2 20:49:19 2014
@@ -517,6 +517,11 @@ public class HRegionServer implements HR
int maxPreloadThreads =
conf.getInt(HConstants.MAX_PRELOAD_THREAD_COUNT, HConstants.DEFAULT_MAX_PRELOAD_THREAD_COUNT);
PreloadThreadPool.constructPreloaderThreadPool(corePreloadThreads, maxPreloadThreads);
+
+ // Configure use of Guava bytes comparator.
+ Bytes.useGuavaBytesComparision = conf.getBoolean(
+ HConstants.USE_GUAVA_BYTES_COMPARISION,
+ HConstants.DEFAULT_USE_GUAVA_BYTES_COMPARISION);
}
/**
Modified: hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/util/Bytes.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/util/Bytes.java?rev=1584166&r1=1584165&r2=1584166&view=diff
==============================================================================
--- hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/util/Bytes.java (original)
+++ hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/util/Bytes.java Wed Apr 2 20:49:19 2014
@@ -23,8 +23,12 @@ import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
+import java.lang.reflect.Field;
import java.math.BigInteger;
import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Iterator;
@@ -41,6 +45,8 @@ import org.apache.thrift.protocol.TProto
import org.apache.thrift.transport.TMemoryBuffer;
import org.apache.thrift.transport.TMemoryInputTransport;
+import sun.misc.Unsafe;
+
import com.facebook.nifty.header.protocol.TFacebookCompactProtocol;
import com.facebook.swift.codec.ThriftCodec;
@@ -970,6 +976,9 @@ public class Bytes {
return compareTo(left, 0, left.length, right, 0, right.length);
}
+ public static boolean useGuavaBytesComparision =
+ HConstants.DEFAULT_USE_GUAVA_BYTES_COMPARISION;
+
/**
* Lexographically compare two arrays.
*
@@ -983,17 +992,218 @@ public class Bytes {
*/
public static int compareTo(byte[] buffer1, int offset1, int length1,
byte[] buffer2, int offset2, int length2) {
- // Bring WritableComparator code local
- int end1 = offset1 + length1;
- int end2 = offset2 + length2;
- for (int i = offset1, j = offset2; i < end1 && j < end2; i++, j++) {
- int a = (buffer1[i] & 0xff);
- int b = (buffer2[j] & 0xff);
- if (a != b) {
- return a - b;
+ if (!useGuavaBytesComparision || (length1 < LONG_BYTES_X_2)
+ || (length2 < LONG_BYTES_X_2)) {
+ // Bring WritableComparator code local
+ int end1 = offset1 + length1;
+ int end2 = offset2 + length2;
+ for (int i = offset1, j = offset2; i < end1 && j < end2; i++, j++) {
+ int a = (buffer1[i] & 0xff);
+ int b = (buffer2[j] & 0xff);
+ if (a != b) {
+ return a - b;
+ }
+ }
+ return length1 - length2;
+ } else {
+ return LexicographicalComparerHolder.BEST_COMPARER.compareTo(
+ buffer1, offset1, length1, buffer2, offset2, length2);
+ }
+ }
+
+ /**
+ * The number of bytes required to represent a primitive {@code long}
+ * value.
+ */
+ public static final int LONG_BYTES = Long.SIZE / Byte.SIZE;
+ public static final int LONG_BYTES_X_2 = LONG_BYTES * 2;
+
+ interface Comparer<T> {
+ abstract public int compareTo(T buffer1, int offset1, int length1,
+ T buffer2, int offset2, int length2);
+ }
+
+ static Comparer<byte[]> lexicographicalComparerJavaImpl() {
+ return LexicographicalComparerHolder.PureJavaComparer.INSTANCE;
+ }
+
+ /**
+ * Provides a lexicographical comparer implementation; either a Java
+ * implementation or a faster implementation based on {@link Unsafe}.
+ *
+ * <p>Uses reflection to gracefully fall back to the Java implementation if
+ * {@code Unsafe} isn't available.
+ */
+ static class LexicographicalComparerHolder {
+ static final String UNSAFE_COMPARER_NAME =
+ LexicographicalComparerHolder.class.getName() + "$UnsafeComparer";
+
+ static final Comparer<byte[]> BEST_COMPARER = getBestComparer();
+ /**
+ * Returns the Unsafe-using Comparer, or falls back to the pure-Java
+ * implementation if unable to do so.
+ */
+ static Comparer<byte[]> getBestComparer() {
+ try {
+ Class<?> theClass = Class.forName(UNSAFE_COMPARER_NAME);
+
+ // yes, UnsafeComparer does implement Comparer<byte[]>
+ @SuppressWarnings("unchecked")
+ Comparer<byte[]> comparer =
+ (Comparer<byte[]>) theClass.getEnumConstants()[0];
+ return comparer;
+ } catch (Throwable t) { // ensure we really catch *everything*
+ return lexicographicalComparerJavaImpl();
+ }
+ }
+
+ enum PureJavaComparer implements Comparer<byte[]> {
+ INSTANCE;
+
+ @Override
+ public int compareTo(byte[] buffer1, int offset1, int length1,
+ byte[] buffer2, int offset2, int length2) {
+ // Short circuit equal case
+ if (buffer1 == buffer2 &&
+ offset1 == offset2 &&
+ length1 == length2) {
+ return 0;
+ }
+ // Bring WritableComparator code local
+ int end1 = offset1 + length1;
+ int end2 = offset2 + length2;
+ for (int i = offset1, j = offset2; i < end1 && j < end2; i++, j++) {
+ int a = (buffer1[i] & 0xff);
+ int b = (buffer2[j] & 0xff);
+ if (a != b) {
+ return a - b;
+ }
+ }
+ return length1 - length2;
+ }
+ }
+
+ enum UnsafeComparer implements Comparer<byte[]> {
+ INSTANCE;
+
+ static final Unsafe theUnsafe;
+
+ /** The offset to the first element in a byte array. */
+ static final int BYTE_ARRAY_BASE_OFFSET;
+
+ static {
+ theUnsafe = (Unsafe) AccessController.doPrivileged(
+ new PrivilegedAction<Object>() {
+ @Override
+ public Object run() {
+ try {
+ Field f = Unsafe.class.getDeclaredField("theUnsafe");
+ f.setAccessible(true);
+ return f.get(null);
+ } catch (NoSuchFieldException e) {
+ // It doesn't matter what we throw;
+ // it's swallowed in getBestComparer().
+ throw new Error();
+ } catch (IllegalAccessException e) {
+ throw new Error();
+ }
+ }
+ });
+
+ BYTE_ARRAY_BASE_OFFSET = theUnsafe.arrayBaseOffset(byte[].class);
+
+ // sanity check - this should never fail
+ if (theUnsafe.arrayIndexScale(byte[].class) != 1) {
+ throw new AssertionError();
+ }
+ }
+
+ static final boolean littleEndian =
+ ByteOrder.nativeOrder().equals(ByteOrder.LITTLE_ENDIAN);
+
+ /**
+ * Returns true if x1 is less than x2, when both values are treated as
+ * unsigned.
+ */
+ static boolean lessThanUnsigned(long x1, long x2) {
+ return (x1 + Long.MIN_VALUE) < (x2 + Long.MIN_VALUE);
+ }
+
+ /**
+ * Lexicographically compare two arrays.
+ *
+ * @param buffer1 left operand
+ * @param buffer2 right operand
+ * @param offset1 Where to start comparing in the left buffer
+ * @param offset2 Where to start comparing in the right buffer
+ * @param length1 How much to compare from the left buffer
+ * @param length2 How much to compare from the right buffer
+ * @return 0 if equal, < 0 if left is less than right, etc.
+ */
+ @Override
+ public int compareTo(byte[] buffer1, int offset1, int length1,
+ byte[] buffer2, int offset2, int length2) {
+ // Short circuit equal case
+ if (buffer1 == buffer2 &&
+ offset1 == offset2 &&
+ length1 == length2) {
+ return 0;
+ }
+ int minLength = Math.min(length1, length2);
+ int minWords = minLength / LONG_BYTES;
+ int offset1Adj = offset1 + BYTE_ARRAY_BASE_OFFSET;
+ int offset2Adj = offset2 + BYTE_ARRAY_BASE_OFFSET;
+
+ /*
+ * Compare 8 bytes at a time. Benchmarking shows comparing 8 bytes at a
+ * time is no slower than comparing 4 bytes at a time even on 32-bit.
+ * On the other hand, it is substantially faster on 64-bit.
+ */
+ for (int i = 0; i < minWords * LONG_BYTES; i += LONG_BYTES) {
+ long lw = theUnsafe.getLong(buffer1, offset1Adj + (long) i);
+ long rw = theUnsafe.getLong(buffer2, offset2Adj + (long) i);
+ long diff = lw ^ rw;
+
+ if (diff != 0) {
+ if (!littleEndian) {
+ return lessThanUnsigned(lw, rw) ? -1 : 1;
+ }
+
+ // Use binary search
+ int n = 0;
+ int y;
+ int x = (int) diff;
+ if (x == 0) {
+ x = (int) (diff >>> 32);
+ n = 32;
+ }
+
+ y = x << 16;
+ if (y == 0) {
+ n += 16;
+ } else {
+ x = y;
+ }
+
+ y = x << 8;
+ if (y == 0) {
+ n += 8;
+ }
+ return (int) (((lw >>> n) & 0xFFL) - ((rw >>> n) & 0xFFL));
+ }
+ }
+
+ // The epilogue to cover the last (minLength % 8) elements.
+ for (int i = minWords * LONG_BYTES; i < minLength; i++) {
+ int a = (buffer1[offset1 + i] & 0xff);
+ int b = (buffer2[offset2 + i] & 0xff);
+ if (a != b) {
+ return a - b;
+ }
+ }
+ return length1 - length2;
}
}
- return length1 - length2;
}
/**
Modified: hbase/branches/0.89-fb/src/test/java/org/apache/hadoop/hbase/util/TestBytes.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.89-fb/src/test/java/org/apache/hadoop/hbase/util/TestBytes.java?rev=1584166&r1=1584165&r2=1584166&view=diff
==============================================================================
--- hbase/branches/0.89-fb/src/test/java/org/apache/hadoop/hbase/util/TestBytes.java (original)
+++ hbase/branches/0.89-fb/src/test/java/org/apache/hadoop/hbase/util/TestBytes.java Wed Apr 2 20:49:19 2014
@@ -24,7 +24,10 @@ import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
+import java.util.ArrayList;
import java.util.Arrays;
+import java.util.List;
+import java.util.Random;
import junit.framework.TestCase;
@@ -289,4 +292,80 @@ public class TestBytes extends TestCase
Assert.assertArrayEquals("appendToTail(a, 0, 6)",
Bytes.appendToTail(a, 2, (byte) 6), new byte[] { 1, 2, 6, 6 });
}
+
+ /**
+ * The rows in a given region follow the following pattern:
+ * [PREFIX BYTES][ID BYTES]
+ *
+ * @param numRows : number of rows to return in the list.
+ * @param prefixLength : length of common prefix.
+ * @param length : length of the rest of the row.
+ * @return : List of rows generated
+ */
+ private List<byte[]> getRowsRandom(int numRows, int prefixLength, int length) {
+ Random r = new Random();
+ byte[] prefixBytes = new byte[prefixLength];
+ r.nextBytes(prefixBytes);
+ List<byte[]> list = new ArrayList<byte[]>();
+ for (int i=0; i<numRows; i++) {
+ byte[] b = new byte[length];
+ r.nextBytes(b);
+ byte[] finalBytes = new byte[prefixLength + length];
+ Bytes.putBytes(finalBytes, 0, prefixBytes, 0, prefixLength);
+ Bytes.putBytes(finalBytes, prefixLength, b, 0, b.length);
+ list.add(finalBytes);
+ }
+ return list;
+ }
+
+ public void testComparatorPerfRandom() {
+ // The rows in a given region follow the following pattern:
+ // [PREFIX BYTES][ID BYTES]
+ // With long prefixes, the comparison using guava is faster.
+ // With fewer common bytes, the guava comparison is slower.
+ for (int PREFIX = 50; PREFIX >= 0; PREFIX -= 5) {
+ int ID = 100;
+ int numRows = 10000;
+ List<byte[]> list = getRowsRandom(numRows, PREFIX, ID);
+
+ // Correctness
+ for (int i=0; i<numRows; i++) {
+ for (int j=0; j<numRows; j++) {
+ Bytes.useGuavaBytesComparision = true;
+ int bg = Bytes.compareTo(list.get(i), list.get(j));
+ Bytes.useGuavaBytesComparision = false;
+ int bs = Bytes.compareTo(list.get(i), list.get(j));
+ assertTrue(bg == bs);
+ }
+ }
+
+ // Comparing the Bytes
+ boolean[] bools = new boolean[]{true, false};
+ long[] timeNs = new long[2];
+
+ for (int idx = 0; idx < 2; idx++) {
+ Bytes.useGuavaBytesComparision = bools[idx];
+ long st = System.nanoTime();
+ for (int i=0; i<numRows; i++) {
+ for (int j=0; j<numRows; j++) {
+ Bytes.compareTo(list.get(i), list.get(j));
+ }
+ }
+ long en = System.nanoTime();
+ timeNs[idx] += (en - st);
+ }
+ double gain = (timeNs[1] - timeNs[0]) / ((double)timeNs[1]);
+ System.out.println("Prefix : " + PREFIX + ", gain : " + gain * 100 + " ");
+ if (PREFIX > 20) {
+ assertTrue(gain > 0.1);
+ assertTrue(timeNs[1] > timeNs[0]);
+ } else if (PREFIX < 10) {
+ assertTrue(gain < -0.1);
+ if (PREFIX == 0) {
+ assertTrue(gain < -0.5);
+ }
+ assertTrue(timeNs[1] < timeNs[0]);
+ }
+ }
+ }
}