GH-45624: [C++][Parquet] BitReader optimize case for num_bits == 1

[mapleFU]

Rationale for this change

The benchmark shows that, in parquet-column-reader-benchmark, the GetValue_ takes half of the times. We can try to optimize this.

What changes are included in this PR?

Avoid call detail::GetValue_ if possible.

Are these changes tested?

Covered by existing

Are there any user-facing changes?

No

• GitHub Issue: [C++] BitReader enhancement when num_bits == 1 #45624

[github-actions]

⚠️ GitHub issue #45624 has been automatically assigned in GitHub to PR creator.

[mapleFU]

On my MacOS M1Pro with release O2 with LLVM-17:

Before:

--------------------------------------------------------------------------------------------------------------------------------------------
Benchmark                                                                                  Time             CPU   Iterations UserCounters...
--------------------------------------------------------------------------------------------------------------------------------------------
ColumnReaderSkipInt32/Repetition:0/BatchSize:1000                                     114159 ns       105934 ns         6386 bytes_per_second=45.0128G/s
ColumnReaderSkipInt32/Repetition:1/BatchSize:1000                                     671094 ns       671074 ns         1042 bytes_per_second=3.78579G/s
ColumnReaderSkipInt32/Repetition:2/BatchSize:1000                                    1558048 ns      1557483 ns          451 bytes_per_second=1.73942G/s
ColumnReaderReadBatchInt32/Repetition:0/BatchSize:1000                                109435 ns       107567 ns         7154 bytes_per_second=44.3293G/s
ColumnReaderReadBatchInt32/Repetition:1/BatchSize:1000                                678187 ns       678090 ns         1032 bytes_per_second=3.74662G/s
ColumnReaderReadBatchInt32/Repetition:2/BatchSize:1000                               1575079 ns      1573793 ns          445 bytes_per_second=1.7214G/s
RecordReaderSkipRecords/Repetition:0/BatchSize:1000                                   107927 ns       107921 ns         6836 bytes_per_second=44.184G/s items_per_second=11.8605G/s
RecordReaderSkipRecords/Repetition:1/BatchSize:1000                                   699862 ns       681619 ns         1043 bytes_per_second=3.72722G/s items_per_second=1.87788G/s
RecordReaderSkipRecords/Repetition:2/BatchSize:1000                                  1968489 ns      1967636 ns          360 bytes_per_second=1.37684G/s items_per_second=650.527M/s
RecordReaderReadRecords/Repetition:0/BatchSize:1000/ReadDense:1                       135719 ns       135545 ns         5505 bytes_per_second=35.1793G/s items_per_second=9.44337G/s
RecordReaderReadRecords/Repetition:0/BatchSize:1000/ReadDense:0                       134429 ns       134208 ns         5412 bytes_per_second=35.5296G/s items_per_second=9.53742G/s
RecordReaderReadRecords/Repetition:1/BatchSize:1000/ReadDense:1                       810494 ns       809804 ns          868 bytes_per_second=3.13723G/s items_per_second=1.58063G/s
RecordReaderReadRecords/Repetition:1/BatchSize:1000/ReadDense:0                      4488228 ns      4474854 ns          158 bytes_per_second=581.363M/s items_per_second=286.043M/s
RecordReaderReadRecords/Repetition:2/BatchSize:1000/ReadDense:1                      1989086 ns      1987642 ns          349 bytes_per_second=1.36298G/s items_per_second=643.979M/s
RecordReaderReadRecords/Repetition:2/BatchSize:1000/ReadDense:0                      6130641 ns      6125723 ns          112 bytes_per_second=452.867M/s items_per_second=208.955M/s
RecordReaderReadAndSkipRecords/Repetition:0/BatchSize:10/LevelsPerPage:80000         3163549 ns      3162216 ns          222 bytes_per_second=1.50792G/s items_per_second=404.779M/s
RecordReaderReadAndSkipRecords/Repetition:0/BatchSize:1000/LevelsPerPage:80000        123934 ns       123942 ns         5851 bytes_per_second=38.4727G/s items_per_second=10.3274G/s
RecordReaderReadAndSkipRecords/Repetition:0/BatchSize:10000/LevelsPerPage:1000000    1294597 ns      1294418 ns          543 bytes_per_second=46.0474G/s items_per_second=12.3608G/s
RecordReaderReadAndSkipRecords/Repetition:1/BatchSize:10/LevelsPerPage:80000        13249022 ns     13240245 ns           53 bytes_per_second=196.485M/s items_per_second=96.6749M/s
RecordReaderReadAndSkipRecords/Repetition:1/BatchSize:1000/LevelsPerPage:80000       2433174 ns      2431853 ns          278 bytes_per_second=1069.77M/s items_per_second=526.348M/s
RecordReaderReadAndSkipRecords/Repetition:1/BatchSize:10000/LevelsPerPage:1000000   28409928 ns     28392640 ns           25 bytes_per_second=1.11716G/s items_per_second=563.526M/s
RecordReaderReadAndSkipRecords/Repetition:2/BatchSize:10/LevelsPerPage:80000        16677514 ns     16630512 ns           43 bytes_per_second=166.81M/s items_per_second=76.967M/s
RecordReaderReadAndSkipRecords/Repetition:2/BatchSize:100/LevelsPerPage:80000        5556215 ns      5519492 ns          130 bytes_per_second=502.608M/s items_per_second=231.905M/s
RecordReaderReadAndSkipRecords/Repetition:2/BatchSize:10000/LevelsPerPage:1000000   44267583 ns     44072625 ns           16 bytes_per_second=785.973M/s items_per_second=363.037M/s
ReadLevels_Rle/MaxLevel:1/NumLevels:8096/BatchSize:1024/LevelRepeatCount:1              2897 ns         2899 ns       241548 bytes_per_second=5.20201G/s items_per_second=2.79281G/s
ReadLevels_Rle/MaxLevel:1/NumLevels:8096/BatchSize:1024/LevelRepeatCount:7              8307 ns         8307 ns        84341 bytes_per_second=1.81527G/s items_per_second=974.563M/s
ReadLevels_Rle/MaxLevel:1/NumLevels:8096/BatchSize:1024/LevelRepeatCount:1024           1033 ns         1035 ns       669901 bytes_per_second=14.5643G/s items_per_second=7.81916G/s
ReadLevels_Rle/MaxLevel:1/NumLevels:8096/BatchSize:2048/LevelRepeatCount:1              2317 ns         2318 ns       302602 bytes_per_second=6.50544G/s items_per_second=3.49258G/s
ReadLevels_Rle/MaxLevel:3/NumLevels:8096/BatchSize:1024/LevelRepeatCount:1              2404 ns         2344 ns       301618 bytes_per_second=6.43295G/s items_per_second=3.45366G/s
ReadLevels_Rle/MaxLevel:3/NumLevels:8096/BatchSize:2048/LevelRepeatCount:1              2075 ns         2076 ns       337047 bytes_per_second=7.26225G/s items_per_second=3.89889G/s
ReadLevels_Rle/MaxLevel:3/NumLevels:8096/BatchSize:1024/LevelRepeatCount:7              7493 ns         7485 ns        92441 bytes_per_second=2.01477G/s items_per_second=1081.67M/s
ReadLevels_BitPack/MaxLevel:1/NumLevels:8096/BatchSize:1024/LevelRepeatCount:1          1651 ns         1650 ns       423798 bytes_per_second=9.13662G/s items_per_second=4.90518G/s
ReadLevels_BitPack/MaxLevel:1/NumLevels:8096/BatchSize:1024/LevelRepeatCount:7          1656 ns         1657 ns       425351 bytes_per_second=9.10184G/s items_per_second=4.88651G/s
ReadLevels_BitPack/MaxLevel:1/NumLevels:8096/BatchSize:1024/LevelRepeatCount:1024       1655 ns         1657 ns       409220 bytes_per_second=9.10111G/s items_per_second=4.88612G/s
ReadLevels_BitPack/MaxLevel:1/NumLevels:8096/BatchSize:2048/LevelRepeatCount:1          1612 ns         1614 ns       432136 bytes_per_second=9.34538G/s items_per_second=5.01726G/s
ReadLevels_BitPack/MaxLevel:3/NumLevels:8096/BatchSize:1024/LevelRepeatCount:1          1750 ns         1754 ns       397256 bytes_per_second=8.59702G/s items_per_second=4.61549G/s
ReadLevels_BitPack/MaxLevel:3/NumLevels:8096/BatchSize:2048/LevelRepeatCount:1          1716 ns         1716 ns       408788 bytes_per_second=8.78623G/s items_per_second=4.71707G/s
ReadLevels_BitPack/MaxLevel:3/NumLevels:8096/BatchSize:1024/LevelRepeatCount:7          1751 ns         1752 ns       397994 bytes_per_second=8.60641G/s items_per_second=4.62053G/s

After:

ColumnReaderSkipInt32/Repetition:0/BatchSize:1000                                     104728 ns       104715 ns         6313 bytes_per_second=45.5369G/s
ColumnReaderSkipInt32/Repetition:1/BatchSize:1000                                     593590 ns       593340 ns         1180 bytes_per_second=4.28177G/s
ColumnReaderSkipInt32/Repetition:2/BatchSize:1000                                    1447860 ns      1442420 ns          488 bytes_per_second=1.87818G/s
ColumnReaderReadBatchInt32/Repetition:0/BatchSize:1000                                107405 ns       107358 ns         6358 bytes_per_second=44.4158G/s
ColumnReaderReadBatchInt32/Repetition:1/BatchSize:1000                                598314 ns       597914 ns         1160 bytes_per_second=4.24901G/s
ColumnReaderReadBatchInt32/Repetition:2/BatchSize:1000                               1450487 ns      1449603 ns          484 bytes_per_second=1.86887G/s
RecordReaderSkipRecords/Repetition:0/BatchSize:1000                                   107744 ns       107665 ns         6477 bytes_per_second=44.289G/s items_per_second=11.8887G/s
RecordReaderSkipRecords/Repetition:1/BatchSize:1000                                   599904 ns       599654 ns         1175 bytes_per_second=4.23668G/s items_per_second=2.13457G/s
RecordReaderSkipRecords/Repetition:2/BatchSize:1000                                  1873631 ns      1869307 ns          381 bytes_per_second=1.44927G/s items_per_second=684.746M/s
RecordReaderReadRecords/Repetition:0/BatchSize:1000/ReadDense:1                       129576 ns       129590 ns         5411 bytes_per_second=36.7957G/s items_per_second=9.87727G/s
RecordReaderReadRecords/Repetition:0/BatchSize:1000/ReadDense:0                       130494 ns       130503 ns         5519 bytes_per_second=36.5385G/s items_per_second=9.80822G/s
RecordReaderReadRecords/Repetition:1/BatchSize:1000/ReadDense:1                       745940 ns       733402 ns          980 bytes_per_second=3.46405G/s items_per_second=1.74529G/s
RecordReaderReadRecords/Repetition:1/BatchSize:1000/ReadDense:0                      4283998 ns      4260679 ns          165 bytes_per_second=610.587M/s items_per_second=300.422M/s
RecordReaderReadRecords/Repetition:2/BatchSize:1000/ReadDense:1                      1910741 ns      1904768 ns          362 bytes_per_second=1.42228G/s items_per_second=671.998M/s
RecordReaderReadRecords/Repetition:2/BatchSize:1000/ReadDense:0                      6738269 ns      6262120 ns          117 bytes_per_second=443.003M/s items_per_second=204.404M/s
RecordReaderReadAndSkipRecords/Repetition:0/BatchSize:10/LevelsPerPage:80000         3185470 ns      3172373 ns          220 bytes_per_second=1.50309G/s items_per_second=403.483M/s
RecordReaderReadAndSkipRecords/Repetition:0/BatchSize:1000/LevelsPerPage:80000        123844 ns       123821 ns         5571 bytes_per_second=38.5103G/s items_per_second=10.3375G/s
RecordReaderReadAndSkipRecords/Repetition:0/BatchSize:10000/LevelsPerPage:1000000    1418022 ns      1368611 ns          501 bytes_per_second=43.5512G/s items_per_second=11.6907G/s
RecordReaderReadAndSkipRecords/Repetition:1/BatchSize:10/LevelsPerPage:80000        13900133 ns     13384222 ns           54 bytes_per_second=194.372M/s items_per_second=95.635M/s
RecordReaderReadAndSkipRecords/Repetition:1/BatchSize:1000/LevelsPerPage:80000       2475976 ns      2456324 ns          284 bytes_per_second=1059.11M/s items_per_second=521.104M/s
RecordReaderReadAndSkipRecords/Repetition:1/BatchSize:10000/LevelsPerPage:1000000   29345005 ns     29020917 ns           24 bytes_per_second=1119.21M/s items_per_second=551.326M/s
RecordReaderReadAndSkipRecords/Repetition:2/BatchSize:10/LevelsPerPage:80000        17031921 ns     16925167 ns           42 bytes_per_second=163.906M/s items_per_second=75.627M/s
RecordReaderReadAndSkipRecords/Repetition:2/BatchSize:100/LevelsPerPage:80000        5533645 ns      5508984 ns          128 bytes_per_second=503.567M/s items_per_second=232.348M/s
RecordReaderReadAndSkipRecords/Repetition:2/BatchSize:10000/LevelsPerPage:1000000   45686734 ns     45607312 ns           16 bytes_per_second=759.525M/s items_per_second=350.821M/s
ReadLevels_Rle/MaxLevel:1/NumLevels:8096/BatchSize:1024/LevelRepeatCount:1              2733 ns         2611 ns       257929 bytes_per_second=5.7755G/s items_per_second=3.1007G/s
ReadLevels_Rle/MaxLevel:1/NumLevels:8096/BatchSize:1024/LevelRepeatCount:7              8815 ns         8593 ns        80671 bytes_per_second=1.75493G/s items_per_second=942.172M/s
ReadLevels_Rle/MaxLevel:1/NumLevels:8096/BatchSize:1024/LevelRepeatCount:1024           1067 ns         1066 ns       657154 bytes_per_second=14.1458G/s items_per_second=7.59446G/s
ReadLevels_Rle/MaxLevel:1/NumLevels:8096/BatchSize:2048/LevelRepeatCount:1              2302 ns         2298 ns       305955 bytes_per_second=6.56181G/s items_per_second=3.52285G/s
ReadLevels_Rle/MaxLevel:3/NumLevels:8096/BatchSize:1024/LevelRepeatCount:1              2335 ns         2331 ns       298706 bytes_per_second=6.46837G/s items_per_second=3.47268G/s
ReadLevels_Rle/MaxLevel:3/NumLevels:8096/BatchSize:2048/LevelRepeatCount:1              2148 ns         2143 ns       319148 bytes_per_second=7.03663G/s items_per_second=3.77776G/s
ReadLevels_Rle/MaxLevel:3/NumLevels:8096/BatchSize:1024/LevelRepeatCount:7              7559 ns         7559 ns        92018 bytes_per_second=1.99507G/s items_per_second=1071.1M/s
ReadLevels_BitPack/MaxLevel:1/NumLevels:8096/BatchSize:1024/LevelRepeatCount:1          1676 ns         1681 ns       418708 bytes_per_second=8.97093G/s items_per_second=4.81623G/s
ReadLevels_BitPack/MaxLevel:1/NumLevels:8096/BatchSize:1024/LevelRepeatCount:7          1684 ns         1682 ns       420145 bytes_per_second=8.9672G/s items_per_second=4.81423G/s
ReadLevels_BitPack/MaxLevel:1/NumLevels:8096/BatchSize:1024/LevelRepeatCount:1024       1642 ns         1644 ns       429106 bytes_per_second=9.1724G/s items_per_second=4.92439G/s
ReadLevels_BitPack/MaxLevel:1/NumLevels:8096/BatchSize:2048/LevelRepeatCount:1          1614 ns         1617 ns       433235 bytes_per_second=9.32817G/s items_per_second=5.00803G/s
ReadLevels_BitPack/MaxLevel:3/NumLevels:8096/BatchSize:1024/LevelRepeatCount:1          1711 ns         1711 ns       411779 bytes_per_second=8.81428G/s items_per_second=4.73213G/s
ReadLevels_BitPack/MaxLevel:3/NumLevels:8096/BatchSize:2048/LevelRepeatCount:1          1679 ns         1680 ns       415300 bytes_per_second=8.97395G/s items_per_second=4.81785G/s
ReadLevels_BitPack/MaxLevel:3/NumLevels:8096/BatchSize:1024/LevelRepeatCount:7          1707 ns         1709 ns       408807 bytes_per_second=8.8216G/s items_per_second=4.73606G/s

[pitrou]

@ursabot please benchmark

[ursabot]

Benchmark runs are scheduled for commit 2f8f27d. Watch https://buildkite.com/apache-arrow and https://conbench.ursa.dev for updates. A comment will be posted here when the runs are complete.

[conbench-apache-arrow]

Thanks for your patience. Conbench analyzed the 4 benchmarking runs that have been run so far on PR commit 2f8f27d.

There were 3 benchmark results indicating a performance regression:

• Pull Request Run on amd64-c6a-4xlarge-linux at 2025-02-26 09:49:32Z
  • BM_ComputeHash (C++) with params=, source=cpp-micro, suite=parquet-bloom-filter-benchmark
  • BM_ComputeHash (C++) with params=, source=cpp-micro, suite=parquet-bloom-filter-benchmark
• and 1 more (see the report linked below)

The full Conbench report has more details.

[pitrou]

Well, the benchmark results don't look terrific. Only test-mac-arm shows an improvement, while on other machines there are no improvements and some regressions might be related.

[pitrou]

Also, the PR complicates already complicated code. I would only be in favor if there was a really sizable improvement with this.

[mapleFU]

ColumnReaderReadBatchInt32/Repetition:1/BatchSize:1000 get a 10% improvement and RecordReaderReadRecords/Repetition:1/BatchSize:1000/ReadDense:0 get a 10% improvement, however, it depends on the batch size, when data is aligned and get a full batch this optimization might not helps, because it will hit the simd unpack code rather than detail::GetValue_

Actually I think the GetBatch would improve when num_bits == 1 if the read batch is not aligned. Let me close this first