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Disable Huffman encoding for small headers (#9260)

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Motivation:

Huffman coding saves only a little space, but has a huge CPU cost

Modification:

Disable huff coding for headers smaller than 512 bytes.  Also, add a
configurable limit to the encoder.

Result:

Faster HPACK

BEFORE:
```
Benchmark                     (duplicates)  (limitToAscii)  (sensitive)  (size)  Mode  Cnt       Score       Error  Units
HpackEncoderBenchmark.encode          true            true         true   SMALL  avgt   10    2572.595 ±    16.184  ns/op
HpackEncoderBenchmark.encode          true            true         true  MEDIUM  avgt   10   19580.815 ±   397.780  ns/op
HpackEncoderBenchmark.encode          true            true         true   LARGE  avgt   10  379456.381 ±  2059.919  ns/op
HpackEncoderBenchmark.encode          true            true        false   SMALL  avgt   10     730.579 ±     8.116  ns/op
HpackEncoderBenchmark.encode          true            true        false  MEDIUM  avgt   10    2087.590 ±    84.644  ns/op
HpackEncoderBenchmark.encode          true            true        false   LARGE  avgt   10   11725.228 ±    89.298  ns/op
HpackEncoderBenchmark.encode          true           false         true   SMALL  avgt   10     555.971 ±     5.120  ns/op
HpackEncoderBenchmark.encode          true           false         true  MEDIUM  avgt   10    2831.874 ±    41.801  ns/op
HpackEncoderBenchmark.encode          true           false         true   LARGE  avgt   10   36054.025 ±   179.504  ns/op
HpackEncoderBenchmark.encode          true           false        false   SMALL  avgt   10     340.337 ±     3.313  ns/op
HpackEncoderBenchmark.encode          true           false        false  MEDIUM  avgt   10    1006.817 ±     8.942  ns/op
HpackEncoderBenchmark.encode          true           false        false   LARGE  avgt   10    8784.168 ±   164.014  ns/op
HpackEncoderBenchmark.encode         false            true         true   SMALL  avgt   10    2561.934 ±    27.056  ns/op
HpackEncoderBenchmark.encode         false            true         true  MEDIUM  avgt   10   22061.105 ±   154.533  ns/op
HpackEncoderBenchmark.encode         false            true         true   LARGE  avgt   10  435744.897 ±  8853.388  ns/op
HpackEncoderBenchmark.encode         false            true        false   SMALL  avgt   10    2737.683 ±    47.142  ns/op
HpackEncoderBenchmark.encode         false            true        false  MEDIUM  avgt   10   22385.146 ±    98.430  ns/op
HpackEncoderBenchmark.encode         false            true        false   LARGE  avgt   10  408159.698 ± 12044.931  ns/op
HpackEncoderBenchmark.encode         false           false         true   SMALL  avgt   10     544.213 ±     3.279  ns/op
HpackEncoderBenchmark.encode         false           false         true  MEDIUM  avgt   10    2908.978 ±    31.026  ns/op
HpackEncoderBenchmark.encode         false           false         true   LARGE  avgt   10   36471.262 ±  1044.010  ns/op
HpackEncoderBenchmark.encode         false           false        false   SMALL  avgt   10     609.305 ±     4.371  ns/op
HpackEncoderBenchmark.encode         false           false        false  MEDIUM  avgt   10    3223.946 ±    23.505  ns/op
HpackEncoderBenchmark.encode         false           false        false   LARGE  avgt   10   39975.152 ±   655.196  ns/op
```

AFTER:
```
NEW AFTER

Benchmark                     (duplicates)  (limitToAscii)  (sensitive)  (size)  Mode  Cnt     Score     Error  Units
HpackEncoderBenchmark.encode          true            true         true   SMALL  avgt    5   379.473 ± 133.815  ns/op
HpackEncoderBenchmark.encode          true            true         true  MEDIUM  avgt    5  1118.772 ±  89.258  ns/op
HpackEncoderBenchmark.encode          true            true         true   LARGE  avgt    5  5366.828 ±  89.746  ns/op
HpackEncoderBenchmark.encode          true            true        false   SMALL  avgt    5   284.401 ±   2.088  ns/op
HpackEncoderBenchmark.encode          true            true        false  MEDIUM  avgt    5   922.805 ±  10.796  ns/op
HpackEncoderBenchmark.encode          true            true        false   LARGE  avgt    5  8727.831 ± 462.138  ns/op
HpackEncoderBenchmark.encode          true           false         true   SMALL  avgt    5   337.093 ±  22.585  ns/op
HpackEncoderBenchmark.encode          true           false         true  MEDIUM  avgt    5   693.689 ±  16.351  ns/op
HpackEncoderBenchmark.encode          true           false         true   LARGE  avgt    5  5616.786 ±  98.647  ns/op
HpackEncoderBenchmark.encode          true           false        false   SMALL  avgt    5   286.708 ±  13.765  ns/op
HpackEncoderBenchmark.encode          true           false        false  MEDIUM  avgt    5   906.279 ±  32.338  ns/op
HpackEncoderBenchmark.encode          true           false        false   LARGE  avgt    5  8304.736 ± 128.584  ns/op
HpackEncoderBenchmark.encode         false            true         true   SMALL  avgt    5   351.381 ±  15.547  ns/op
HpackEncoderBenchmark.encode         false            true         true  MEDIUM  avgt    5  1188.166 ±   7.023  ns/op
HpackEncoderBenchmark.encode         false            true         true   LARGE  avgt    5  6876.009 ±  48.117  ns/op
HpackEncoderBenchmark.encode         false            true        false   SMALL  avgt    5   434.759 ±   8.619  ns/op
HpackEncoderBenchmark.encode         false            true        false  MEDIUM  avgt    5   954.588 ±  58.514  ns/op
HpackEncoderBenchmark.encode         false            true        false   LARGE  avgt    5  8534.017 ± 552.597  ns/op
HpackEncoderBenchmark.encode         false           false         true   SMALL  avgt    5   223.713 ±   4.823  ns/op
HpackEncoderBenchmark.encode         false           false         true  MEDIUM  avgt    5  1181.538 ±  11.851  ns/op
HpackEncoderBenchmark.encode         false           false         true   LARGE  avgt    5  6670.830 ± 267.927  ns/op
HpackEncoderBenchmark.encode         false           false        false   SMALL  avgt    5   424.609 ±  27.477  ns/op
HpackEncoderBenchmark.encode         false           false        false  MEDIUM  avgt    5  1003.578 ±  53.991  ns/op
HpackEncoderBenchmark.encode         false           false        false   LARGE  avgt    5  8428.932 ± 102.838  ns/op
```
This commit is contained in:
Carl Mastrangelo 2019-07-01 12:00:21 -07:00 committed by Norman Maurer
parent f0afd7cfcd
commit e96c37dea7
4 changed files with 21 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2HeadersEncoder.java
View File

@ -43,7 +43,13 @@ public class DefaultHttp2HeadersEncoder implements Http2HeadersEncoder, Http2Hea
public DefaultHttp2HeadersEncoder(SensitivityDetector sensitivityDetector, boolean ignoreMaxHeaderListSize, public DefaultHttp2HeadersEncoder(SensitivityDetector sensitivityDetector, boolean ignoreMaxHeaderListSize,
int dynamicTableArraySizeHint) { int dynamicTableArraySizeHint) {
this(sensitivityDetector, new HpackEncoder(ignoreMaxHeaderListSize, dynamicTableArraySizeHint)); this(sensitivityDetector, ignoreMaxHeaderListSize, dynamicTableArraySizeHint, HpackEncoder.HUFF_CODE_THRESHOLD);
}
public DefaultHttp2HeadersEncoder(SensitivityDetector sensitivityDetector, boolean ignoreMaxHeaderListSize,
int dynamicTableArraySizeHint, int huffCodeThreshold) {
this(sensitivityDetector,
new HpackEncoder(ignoreMaxHeaderListSize, dynamicTableArraySizeHint, huffCodeThreshold));
} }
/** /**

12
codec-http2/src/main/java/io/netty/handler/codec/http2/HpackEncoder.java
View File

@ -54,6 +54,7 @@ import static java.lang.Math.max;
import static java.lang.Math.min; import static java.lang.Math.min;
final class HpackEncoder { final class HpackEncoder {
static final int HUFF_CODE_THRESHOLD = 512;
// a linked hash map of header fields // a linked hash map of header fields
private final HeaderEntry[] headerFields; private final HeaderEntry[] headerFields;
private final HeaderEntry head = new HeaderEntry(-1, AsciiString.EMPTY_STRING, private final HeaderEntry head = new HeaderEntry(-1, AsciiString.EMPTY_STRING,
@ -61,6 +62,7 @@ final class HpackEncoder {
private final HpackHuffmanEncoder hpackHuffmanEncoder = new HpackHuffmanEncoder(); private final HpackHuffmanEncoder hpackHuffmanEncoder = new HpackHuffmanEncoder();
private final byte hashMask; private final byte hashMask;
private final boolean ignoreMaxHeaderListSize; private final boolean ignoreMaxHeaderListSize;
private final int huffCodeThreshold;
private long size; private long size;
private long maxHeaderTableSize; private long maxHeaderTableSize;
private long maxHeaderListSize; private long maxHeaderListSize;
@ -76,13 +78,13 @@ final class HpackEncoder {
* Creates a new encoder. * Creates a new encoder.
*/ */
HpackEncoder(boolean ignoreMaxHeaderListSize) { HpackEncoder(boolean ignoreMaxHeaderListSize) {
this(ignoreMaxHeaderListSize, 16); this(ignoreMaxHeaderListSize, 16, HUFF_CODE_THRESHOLD);
} }
/** /**
* Creates a new encoder. * Creates a new encoder.
*/ */
HpackEncoder(boolean ignoreMaxHeaderListSize, int arraySizeHint) { HpackEncoder(boolean ignoreMaxHeaderListSize, int arraySizeHint, int huffCodeThreshold) {
this.ignoreMaxHeaderListSize = ignoreMaxHeaderListSize; this.ignoreMaxHeaderListSize = ignoreMaxHeaderListSize;
maxHeaderTableSize = DEFAULT_HEADER_TABLE_SIZE; maxHeaderTableSize = DEFAULT_HEADER_TABLE_SIZE;
maxHeaderListSize = MAX_HEADER_LIST_SIZE; maxHeaderListSize = MAX_HEADER_LIST_SIZE;
@ -91,6 +93,7 @@ final class HpackEncoder {
headerFields = new HeaderEntry[findNextPositivePowerOfTwo(max(2, min(arraySizeHint, 128)))]; headerFields = new HeaderEntry[findNextPositivePowerOfTwo(max(2, min(arraySizeHint, 128)))];
hashMask = (byte) (headerFields.length - 1); hashMask = (byte) (headerFields.length - 1);
head.before = head.after = head; head.before = head.after = head;
this.huffCodeThreshold = huffCodeThreshold;
} }
/** /**
@ -250,8 +253,9 @@ final class HpackEncoder {
* Encode string literal according to Section 5.2. * Encode string literal according to Section 5.2.
*/ */
private void encodeStringLiteral(ByteBuf out, CharSequence string) { private void encodeStringLiteral(ByteBuf out, CharSequence string) {
int huffmanLength = hpackHuffmanEncoder.getEncodedLength(string); int huffmanLength;
if (huffmanLength < string.length()) { if (string.length() >= huffCodeThreshold
&& (huffmanLength = hpackHuffmanEncoder.getEncodedLength(string)) < string.length()) {
encodeInteger(out, 0x80, 7, huffmanLength); encodeInteger(out, 0x80, 7, huffmanLength);
hpackHuffmanEncoder.encode(out, string); hpackHuffmanEncoder.encode(out, string);
} else { } else {

6
codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2FrameWriterTest.java
View File

@ -15,6 +15,7 @@
package io.netty.handler.codec.http2; package io.netty.handler.codec.http2;
import io.netty.buffer.ByteBuf; import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufUtil;
import io.netty.buffer.Unpooled; import io.netty.buffer.Unpooled;
import io.netty.buffer.UnpooledByteBufAllocator; import io.netty.buffer.UnpooledByteBufAllocator;
import io.netty.channel.Channel; import io.netty.channel.Channel;
@ -65,8 +66,11 @@ public class DefaultHttp2FrameWriterTest {
@Before @Before
public void setUp() throws Exception { public void setUp() throws Exception {
MockitoAnnotations.initMocks(this); MockitoAnnotations.initMocks(this);
http2HeadersEncoder = new DefaultHttp2HeadersEncoder(
Http2HeadersEncoder.NEVER_SENSITIVE, new HpackEncoder(false, 16, 0));
frameWriter = new DefaultHttp2FrameWriter(); frameWriter = new DefaultHttp2FrameWriter(new DefaultHttp2HeadersEncoder(
Http2HeadersEncoder.NEVER_SENSITIVE, new HpackEncoder(false, 16, 0)));
outbound = Unpooled.buffer(); outbound = Unpooled.buffer();

2
codec-http2/src/test/java/io/netty/handler/codec/http2/Http2TestUtil.java
View File

@ -116,7 +116,7 @@ public final class Http2TestUtil {
public static HpackEncoder newTestEncoder(boolean ignoreMaxHeaderListSize, public static HpackEncoder newTestEncoder(boolean ignoreMaxHeaderListSize,
long maxHeaderListSize, long maxHeaderTableSize) throws Http2Exception { long maxHeaderListSize, long maxHeaderTableSize) throws Http2Exception {
HpackEncoder hpackEncoder = new HpackEncoder(); HpackEncoder hpackEncoder = new HpackEncoder(false, 16, 0);
ByteBuf buf = Unpooled.buffer(); ByteBuf buf = Unpooled.buffer();
try { try {
hpackEncoder.setMaxHeaderTableSize(buf, maxHeaderTableSize); hpackEncoder.setMaxHeaderTableSize(buf, maxHeaderTableSize);