Use branchless way to speedup filterCompetitiveHits

[HUSTERGS]

Description

This PR is part of #14896 from the comment . Propose to modify the filterCompetitiveHits in a branchless way, hopefully we can get partially auto-vectorized.

Here is the luceneutil result on wikimediumall with searchConcurrency=0, taskCountPerCat=5, taskRepeatCount=50 after 20 iterations:

                            TaskQPS baseline      StdDevQPS my_modified_version      StdDev                Pct diff p-value
      FilteredOr2Terms2StopWords       67.28      (6.6%)       65.96      (6.8%)   -2.0% ( -14% -   12%) 0.355
                       OrHighMed       92.82      (3.8%)       91.23      (4.1%)   -1.7% (  -9% -    6%) 0.171
               CombinedOrHighMed       28.37      (6.3%)       27.89      (5.8%)   -1.7% ( -13% -   11%) 0.376
              CombinedAndHighMed       29.11      (5.4%)       28.61      (4.5%)   -1.7% ( -11% -    8%) 0.280
                 AndHighOrMedMed       18.44      (3.3%)       18.14      (2.8%)   -1.6% (  -7% -    4%) 0.089
                 DismaxOrHighMed       67.66      (3.7%)       66.60      (3.9%)   -1.6% (  -8% -    6%) 0.194
                         TermB1M      595.71      (3.6%)      586.50      (4.9%)   -1.5% (  -9% -    7%) 0.257
                          Term1M      596.06      (3.6%)      586.93      (5.0%)   -1.5% (  -9% -    7%) 0.266
                            Term      595.68      (3.6%)      586.74      (5.0%)   -1.5% (  -9% -    7%) 0.274
                         Term10K      594.97      (3.8%)      586.18      (4.9%)   -1.5% (  -9% -    7%) 0.283
                       TermB1M1P      595.60      (3.7%)      586.84      (4.9%)   -1.5% (  -9% -    7%) 0.286
                         Term100      595.04      (3.6%)      586.49      (5.0%)   -1.4% (  -9% -    7%) 0.294
                       CountTerm     7970.70      (5.6%)     7856.82      (5.6%)   -1.4% ( -12% -   10%) 0.422
                    FilteredTerm       87.37      (4.3%)       86.13      (4.6%)   -1.4% (  -9% -    7%) 0.314
               FilteredOrHighMed       54.11      (5.0%)       53.35      (5.3%)   -1.4% ( -11% -    9%) 0.388
                      OrHighRare      121.49      (3.2%)      119.92      (3.4%)   -1.3% (  -7% -    5%) 0.220
                 CountOrHighHigh       64.26      (2.6%)       63.43      (1.9%)   -1.3% (  -5% -    3%) 0.075
                DismaxOrHighHigh       47.55      (2.5%)       46.94      (2.9%)   -1.3% (  -6% -    4%) 0.135
            FilteredAndStopWords       12.03      (2.8%)       11.89      (3.7%)   -1.2% (  -7% -    5%) 0.270
                FilteredOr3Terms       59.60      (4.5%)       58.92      (4.7%)   -1.2% (  -9% -    8%) 0.426
                   TermTitleSort       73.24      (4.2%)       72.44      (4.2%)   -1.1% (  -9% -    7%) 0.410
                     CountOrMany        6.48      (2.3%)        6.41      (1.9%)   -1.1% (  -5% -    3%) 0.108
             CountFilteredOrMany        6.08      (1.9%)        6.02      (1.5%)   -1.0% (  -4% -    2%) 0.061
                  CountOrHighMed       97.07      (2.8%)       96.11      (2.6%)   -1.0% (  -6% -    4%) 0.250
                      TermDTSort      193.19      (2.7%)      191.42      (2.4%)   -0.9% (  -5% -    4%) 0.252
                   TermMonthSort     2982.24      (3.7%)     2958.62      (3.4%)   -0.8% (  -7% -    6%) 0.482
             FilteredAndHighHigh       15.23      (2.8%)       15.12      (3.6%)   -0.8% (  -7% -    5%) 0.446
                          Fuzzy1       50.54      (3.2%)       50.15      (3.7%)   -0.8% (  -7% -    6%) 0.473
              FilteredOrHighHigh       18.16      (3.2%)       18.02      (3.2%)   -0.8% (  -6% -    5%) 0.447
                 CountAndHighMed       94.00      (2.8%)       93.32      (2.8%)   -0.7% (  -6% -    5%) 0.416
                      DismaxTerm      657.56      (3.5%)      652.99      (3.8%)   -0.7% (  -7% -    6%) 0.547
                CountAndHighHigh       62.08      (1.8%)       61.67      (1.1%)   -0.7% (  -3% -    2%) 0.161
                          Fuzzy2       45.36      (1.8%)       45.11      (2.4%)   -0.6% (  -4% -    3%) 0.399
                  FilteredPhrase       12.66      (2.3%)       12.59      (2.3%)   -0.6% (  -5% -    4%) 0.433
                     AndHighHigh       28.01      (3.5%)       27.85      (4.2%)   -0.5% (  -8% -    7%) 0.658
                    CombinedTerm       14.62      (3.8%)       14.55      (4.9%)   -0.5% (  -8% -    8%) 0.705
                          Phrase        9.91      (2.1%)        9.86      (2.2%)   -0.5% (  -4% -    3%) 0.453
              Or2Terms2StopWords       79.00      (7.2%)       78.61      (7.4%)   -0.5% ( -14% -   15%) 0.829
                IntervalsOrdered        2.96      (2.4%)        2.94      (2.6%)   -0.5% (  -5% -    4%) 0.564
               FilteredAnd3Terms      132.86      (3.0%)      132.29      (3.4%)   -0.4% (  -6% -    6%) 0.670
             FilteredOrStopWords       11.15      (2.2%)       11.11      (2.4%)   -0.4% (  -4% -    4%) 0.591
             And2Terms2StopWords       76.63      (8.2%)       76.34      (8.3%)   -0.4% ( -15% -   17%) 0.882
         CountFilteredOrHighHigh       25.24      (1.3%)       25.16      (1.3%)   -0.3% (  -2% -    2%) 0.451
          CountFilteredOrHighMed       29.64      (1.4%)       29.56      (1.3%)   -0.2% (  -2% -    2%) 0.570
                          IntNRQ       48.50      (2.2%)       48.38      (2.3%)   -0.2% (  -4% -    4%) 0.741
                  FilteredIntNRQ       48.16      (2.2%)       48.10      (2.3%)   -0.1% (  -4% -    4%) 0.868
             CountFilteredIntNRQ       22.17      (1.3%)       22.14      (1.8%)   -0.1% (  -3% -    3%) 0.829
                  FilteredOrMany        5.11      (3.0%)        5.11      (2.7%)    0.0% (  -5% -    5%) 0.993
     FilteredAnd2Terms2StopWords       77.42      (6.3%)       77.46      (6.5%)    0.0% ( -12% -   13%) 0.984
                    SloppyPhrase        1.47      (4.1%)        1.47      (4.6%)    0.1% (  -8% -    9%) 0.928
                AndMedOrHighHigh       21.15      (1.9%)       21.19      (1.8%)    0.2% (  -3% -    3%) 0.719
                          IntSet      401.08      (4.4%)      402.07      (3.9%)    0.2% (  -7% -    8%) 0.851
               TermDayOfYearSort      356.48      (1.1%)      357.37      (1.2%)    0.2% (  -2% -    2%) 0.490
                        SpanNear        3.07      (4.9%)        3.08      (4.9%)    0.3% (  -9% -   10%) 0.858
                      AndHighMed       70.36      (3.1%)       70.60      (3.0%)    0.3% (  -5% -    6%) 0.722
                         Respell       43.66      (2.9%)       43.81      (2.3%)    0.3% (  -4% -    5%) 0.674
              FilteredAndHighMed       45.14      (2.9%)       45.33      (3.3%)    0.4% (  -5% -    6%) 0.671
             CountFilteredPhrase       11.53      (2.0%)       11.59      (2.2%)    0.5% (  -3% -    4%) 0.435
                 FilteredPrefix3       93.08      (3.5%)       93.69      (2.6%)    0.7% (  -5% -    6%) 0.494
              CombinedOrHighHigh        7.09      (5.4%)        7.14      (5.8%)    0.7% (  -9% -   12%) 0.700
                      OrHighHigh       26.79      (2.4%)       26.97      (4.2%)    0.7% (  -5% -    7%) 0.530
                         Prefix3       99.61      (3.8%)      100.33      (2.5%)    0.7% (  -5% -    7%) 0.483
             CombinedAndHighHigh        7.30      (1.8%)        7.36      (1.9%)    0.8% (  -2% -    4%) 0.161
                        Wildcard       58.26      (3.3%)       58.86      (2.9%)    1.0% (  -4% -    7%) 0.287
                     OrStopWords       10.76      (5.4%)       10.88      (7.2%)    1.1% ( -10% -   14%) 0.574
                     CountPhrase        3.30      (3.6%)        3.34      (2.1%)    1.4% (  -4% -    7%) 0.131
                          OrMany        5.87      (3.0%)        6.03      (4.3%)    2.7% (  -4% -   10%) 0.019
                        Or3Terms       83.12      (2.8%)       85.65      (4.4%)    3.0% (  -4% -   10%) 0.009
                       And3Terms       91.23      (3.3%)       94.32      (4.2%)    3.4% (  -3% -   11%) 0.004
                    AndStopWords       10.01      (3.7%)       10.48      (6.1%)    4.7% (  -4% -   15%) 0.003

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[ChrisHegarty]

LGTM

[jpountz]

I suggested an alternative impl as a follow-up to Robert's comment, that uses conditional moves and looks faster: https://github.com/apache/lucene/pull/14906/files#r2189422844

[HUSTERGS]

I suggested an alternative impl as a follow-up to Robert's comment, that uses conditional moves and looks faster: https://github.com/apache/lucene/pull/14906/files#r2189422844

Thank you !! That is amazing ! I pushed another commit according to your suggestion.

[jpountz]

The new impl is slightly slower on my ARM Mac, but it's still a similar order of magnitude and much faster than the baseline, and the code looks more idiomatic, so I think we're good to merge.

Benchmark                                     (minScoreInclusive)  (size)   Mode  Cnt      Score      Error   Units
CompetitiveBenchmark.baseline                                   0     128  thrpt    5  40218,516 ± 5935,656  ops/ms
CompetitiveBenchmark.baseline                                 0.2     128  thrpt    5   4247,052 ±  216,541  ops/ms
CompetitiveBenchmark.baseline                                 0.4     128  thrpt    5   2401,350 ±   32,013  ops/ms
CompetitiveBenchmark.baseline                                 0.5     128  thrpt    5   2117,681 ±   14,486  ops/ms
CompetitiveBenchmark.baseline                                 0.8     128  thrpt    5   4630,407 ±  235,055  ops/ms
CompetitiveBenchmark.branchlessCandidate                        0     128  thrpt    5  39799,572 ± 8695,960  ops/ms
CompetitiveBenchmark.branchlessCandidate                      0.2     128  thrpt    5  11255,718 ±  579,988  ops/ms
CompetitiveBenchmark.branchlessCandidate                      0.4     128  thrpt    5  11181,453 ±  418,377  ops/ms
CompetitiveBenchmark.branchlessCandidate                      0.5     128  thrpt    5  11238,359 ±  367,859  ops/ms
CompetitiveBenchmark.branchlessCandidate                      0.8     128  thrpt    5  11120,788 ±  263,541  ops/ms
CompetitiveBenchmark.branchlessCandidateCmov                    0     128  thrpt    5  43470,171 ± 4588,605  ops/ms
CompetitiveBenchmark.branchlessCandidateCmov                  0.2     128  thrpt    5  10343,082 ±  324,145  ops/ms
CompetitiveBenchmark.branchlessCandidateCmov                  0.4     128  thrpt    5  10286,804 ±   77,779  ops/ms
CompetitiveBenchmark.branchlessCandidateCmov                  0.5     128  thrpt    5  10256,737 ±  123,636  ops/ms
CompetitiveBenchmark.branchlessCandidateCmov                  0.8     128  thrpt    5  10306,218 ±  169,973  ops/ms

[jpountz]

Nightly benchmarks caught up with this change. Good speedups on many queries. https://benchmarks.mikemccandless.com/OrMany.html

[jpountz]

I pushed an annotation.

[msokolov]

it's crazy that this helps. I have to think about things in a new way. I mean my old way of thinking is that the fewer things you ask the computer to do, the less work it has to do :)

[dweiss]

it's crazy that this helps. I have to think about things in a new way. I mean my old way of thinking is that the fewer things you ask the computer to do, the less work it has to do :)

I'm the same way... but I think this stopped being true somewhere around mid- 90s. :)