Disable Huffman encoding for small headers (#9260)
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
Norman Maurer
parent
f0afd7cfcd
commit
e96c37dea7
@ -43,7 +43,13 @@ public class DefaultHttp2HeadersEncoder implements Http2HeadersEncoder, Http2Hea
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public DefaultHttp2HeadersEncoder(SensitivityDetector sensitivityDetector, boolean ignoreMaxHeaderListSize,
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int dynamicTableArraySizeHint) {
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this(sensitivityDetector, new HpackEncoder(ignoreMaxHeaderListSize, dynamicTableArraySizeHint));
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this(sensitivityDetector, ignoreMaxHeaderListSize, dynamicTableArraySizeHint, HpackEncoder.HUFF_CODE_THRESHOLD);
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}
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public DefaultHttp2HeadersEncoder(SensitivityDetector sensitivityDetector, boolean ignoreMaxHeaderListSize,
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int dynamicTableArraySizeHint, int huffCodeThreshold) {
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this(sensitivityDetector,
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new HpackEncoder(ignoreMaxHeaderListSize, dynamicTableArraySizeHint, huffCodeThreshold));
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}
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/**
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@ -54,6 +54,7 @@ import static java.lang.Math.max;
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import static java.lang.Math.min;
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final class HpackEncoder {
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static final int HUFF_CODE_THRESHOLD = 512;
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// a linked hash map of header fields
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private final HeaderEntry[] headerFields;
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private final HeaderEntry head = new HeaderEntry(-1, AsciiString.EMPTY_STRING,
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@ -61,6 +62,7 @@ final class HpackEncoder {
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private final HpackHuffmanEncoder hpackHuffmanEncoder = new HpackHuffmanEncoder();
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private final byte hashMask;
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private final boolean ignoreMaxHeaderListSize;
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private final int huffCodeThreshold;
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private long size;
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private long maxHeaderTableSize;
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private long maxHeaderListSize;
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@ -76,13 +78,13 @@ final class HpackEncoder {
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* Creates a new encoder.
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*/
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HpackEncoder(boolean ignoreMaxHeaderListSize) {
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this(ignoreMaxHeaderListSize, 16);
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this(ignoreMaxHeaderListSize, 16, HUFF_CODE_THRESHOLD);
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}
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/**
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* Creates a new encoder.
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*/
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HpackEncoder(boolean ignoreMaxHeaderListSize, int arraySizeHint) {
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HpackEncoder(boolean ignoreMaxHeaderListSize, int arraySizeHint, int huffCodeThreshold) {
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this.ignoreMaxHeaderListSize = ignoreMaxHeaderListSize;
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maxHeaderTableSize = DEFAULT_HEADER_TABLE_SIZE;
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maxHeaderListSize = MAX_HEADER_LIST_SIZE;
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@ -91,6 +93,7 @@ final class HpackEncoder {
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headerFields = new HeaderEntry[findNextPositivePowerOfTwo(max(2, min(arraySizeHint, 128)))];
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hashMask = (byte) (headerFields.length - 1);
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head.before = head.after = head;
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this.huffCodeThreshold = huffCodeThreshold;
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}
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/**
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@ -250,8 +253,9 @@ final class HpackEncoder {
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* Encode string literal according to Section 5.2.
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*/
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private void encodeStringLiteral(ByteBuf out, CharSequence string) {
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int huffmanLength = hpackHuffmanEncoder.getEncodedLength(string);
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if (huffmanLength < string.length()) {
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int huffmanLength;
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if (string.length() >= huffCodeThreshold
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&& (huffmanLength = hpackHuffmanEncoder.getEncodedLength(string)) < string.length()) {
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encodeInteger(out, 0x80, 7, huffmanLength);
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hpackHuffmanEncoder.encode(out, string);
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} else {
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@ -15,6 +15,7 @@
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package io.netty.handler.codec.http2;
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import io.netty.buffer.ByteBuf;
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import io.netty.buffer.ByteBufUtil;
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import io.netty.buffer.Unpooled;
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import io.netty.buffer.UnpooledByteBufAllocator;
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import io.netty.channel.Channel;
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@ -65,8 +66,11 @@ public class DefaultHttp2FrameWriterTest {
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@Before
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public void setUp() throws Exception {
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MockitoAnnotations.initMocks(this);
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http2HeadersEncoder = new DefaultHttp2HeadersEncoder(
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Http2HeadersEncoder.NEVER_SENSITIVE, new HpackEncoder(false, 16, 0));
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frameWriter = new DefaultHttp2FrameWriter();
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frameWriter = new DefaultHttp2FrameWriter(new DefaultHttp2HeadersEncoder(
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Http2HeadersEncoder.NEVER_SENSITIVE, new HpackEncoder(false, 16, 0)));
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outbound = Unpooled.buffer();
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@ -116,7 +116,7 @@ public final class Http2TestUtil {
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public static HpackEncoder newTestEncoder(boolean ignoreMaxHeaderListSize,
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long maxHeaderListSize, long maxHeaderTableSize) throws Http2Exception {
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HpackEncoder hpackEncoder = new HpackEncoder();
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HpackEncoder hpackEncoder = new HpackEncoder(false, 16, 0);
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ByteBuf buf = Unpooled.buffer();
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try {
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hpackEncoder.setMaxHeaderTableSize(buf, maxHeaderTableSize);
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