• Klaus Post's avatar
    compress/flate: optimize huffman bit encoder · 53984e5b
    Klaus Post authored
    Part 1 of optimizing the deflater. This optimizes the bitwriter by:
    
    * Removing allocations.
    * Storing compound values for bit codes instead of 2 separate tables.
    * Accumulate 48 bits between writes instead of 24.
    * Inline bit flushing.
    
    This also contains code that will be used in later CL's
    (writeBlockDynamic, writeBlockHuff).
    
    Tests for Huffman bit writer encoding regressions has been added.
    
    name                       old speed      new speed      delta
    EncodeDigitsSpeed1e4-4     19.3MB/s ± 1%  21.6MB/s ± 1%  +11.77%
    EncodeDigitsSpeed1e5-4     25.0MB/s ± 6%  30.7MB/s ± 1%  +22.70%
    EncodeDigitsSpeed1e6-4     28.2MB/s ± 1%  32.3MB/s ± 1%  +14.64%
    EncodeDigitsDefault1e4-4   13.3MB/s ± 0%  14.2MB/s ± 1%   +7.07%
    EncodeDigitsDefault1e5-4   6.43MB/s ± 1%  6.64MB/s ± 1%   +3.27%
    EncodeDigitsDefault1e6-4   5.81MB/s ± 0%  5.85MB/s ± 1%   +0.69%
    EncodeDigitsCompress1e4-4  13.2MB/s ± 0%  14.4MB/s ± 0%   +9.10%
    EncodeDigitsCompress1e5-4  6.40MB/s ± 1%  6.61MB/s ± 0%   +3.20%
    EncodeDigitsCompress1e6-4  5.80MB/s ± 1%  5.90MB/s ± 1%   +1.64%
    EncodeTwainSpeed1e4-4      18.4MB/s ± 1%  20.7MB/s ± 1%  +12.72%
    EncodeTwainSpeed1e5-4      27.7MB/s ± 1%  31.0MB/s ± 1%  +11.78%
    EncodeTwainSpeed1e6-4      29.1MB/s ± 0%  32.9MB/s ± 2%  +13.25%
    EncodeTwainDefault1e4-4    12.4MB/s ± 0%  13.1MB/s ± 1%   +5.88%
    EncodeTwainDefault1e5-4    7.52MB/s ± 1%  7.83MB/s ± 0%   +4.19%
    EncodeTwainDefault1e6-4    7.08MB/s ± 1%  7.26MB/s ± 0%   +2.54%
    EncodeTwainCompress1e4-4   12.0MB/s ± 1%  12.8MB/s ± 1%   +6.70%
    EncodeTwainCompress1e5-4   5.96MB/s ± 1%  6.16MB/s ± 0%   +3.27%
    EncodeTwainCompress1e6-4   5.37MB/s ± 0%  5.39MB/s ± 1%   +0.47%
    
    >Allocations:
    
    benchmark                              old allocs     new allocs     delta
    BenchmarkEncodeDigitsSpeed1e4-4        50             0              -100.00%
    BenchmarkEncodeDigitsSpeed1e5-4        110            0              -100.00%
    BenchmarkEncodeDigitsSpeed1e6-4        1032           0              -100.00%
    BenchmarkEncodeDigitsDefault1e4-4      56             0              -100.00%
    BenchmarkEncodeDigitsDefault1e5-4      120            0              -100.00%
    BenchmarkEncodeDigitsDefault1e6-4      966            0              -100.00%
    BenchmarkEncodeDigitsCompress1e4-4     56             0              -100.00%
    BenchmarkEncodeDigitsCompress1e5-4     120            0              -100.00%
    BenchmarkEncodeDigitsCompress1e6-4     966            0              -100.00%
    BenchmarkEncodeTwainSpeed1e4-4         58             0              -100.00%
    BenchmarkEncodeTwainSpeed1e5-4         132            0              -100.00%
    BenchmarkEncodeTwainSpeed1e6-4         1082           0              -100.00%
    BenchmarkEncodeTwainDefault1e4-4       52             0              -100.00%
    BenchmarkEncodeTwainDefault1e5-4       126            0              -100.00%
    BenchmarkEncodeTwainDefault1e6-4       886            0              -100.00%
    BenchmarkEncodeTwainCompress1e4-4      52             0              -100.00%
    BenchmarkEncodeTwainCompress1e5-4      120            0              -100.00%
    BenchmarkEncodeTwainCompress1e6-4      880            0              -100.00%
    
    benchmark                              old bytes     new bytes     delta
    BenchmarkEncodeDigitsSpeed1e4-4        4288          2             -99.95%
    BenchmarkEncodeDigitsSpeed1e5-4        8896          15            -99.83%
    BenchmarkEncodeDigitsSpeed1e6-4        84098         153           -99.82%
    BenchmarkEncodeDigitsDefault1e4-4      4480          3             -99.93%
    BenchmarkEncodeDigitsDefault1e5-4      9216          76            -99.18%
    BenchmarkEncodeDigitsDefault1e6-4      73920         768           -98.96%
    BenchmarkEncodeDigitsCompress1e4-4     4480          3             -99.93%
    BenchmarkEncodeDigitsCompress1e5-4     9216          76            -99.18%
    BenchmarkEncodeDigitsCompress1e6-4     73920         768           -98.96%
    BenchmarkEncodeTwainSpeed1e4-4         4544          2             -99.96%
    BenchmarkEncodeTwainSpeed1e5-4         9600          15            -99.84%
    BenchmarkEncodeTwainSpeed1e6-4         77633         153           -99.80%
    BenchmarkEncodeTwainDefault1e4-4       4352          3             -99.93%
    BenchmarkEncodeTwainDefault1e5-4       9408          76            -99.19%
    BenchmarkEncodeTwainDefault1e6-4       65984         768           -98.84%
    BenchmarkEncodeTwainCompress1e4-4      4352          3             -99.93%
    BenchmarkEncodeTwainCompress1e5-4      9216          76            -99.18%
    BenchmarkEncodeTwainCompress1e6-4      65792         768           -98.83%
    
    Updates #14258
    
    Change-Id: Ibaa97b9619743ad623094727228eb2ada1ec7f1f
    Reviewed-on: https://go-review.googlesource.com/19336Reviewed-by: 's avatarNigel Tao <nigeltao@golang.org>
    Reviewed-by: 's avatarJoe Tsai <joetsai@digital-static.net>
    Run-TryBot: Joe Tsai <joetsai@digital-static.net>
    TryBot-Result: Gobot Gobot <gobot@golang.org>
    53984e5b
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