Count directly into the values array in FastTaxonomyFacetCounts#countAl [LUCENE-10379]

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This breaks out one of the two optimizations proposed in #11386. As part of trying to track down the regressions caused by #11386, I propose we push just this one optimization independently (see LUCENE-10374).

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Migrated from LUCENE-10379 by Greg Miller (@gsmiller), resolved Jan 18 2022
Pull requests: #605, #610

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ASF subversion and git services (migrated from JIRA)

Commit 2f5e3c3 in lucene's branch refs/heads/main from Greg Miller
https://gitbox.apache.org/repos/asf?p=lucene.git;h=2f5e3c3

LUCENE-10379: Count directly into the dense values array in FastTaxonomyFacetCounts#countAll (#605)

Co-authored-by: guofeng.my <guofeng.my@bytedance.com>

[asfimport]

Greg Miller (@gsmiller) (migrated from JIRA)

Merged this and will watch the next nightly bench runs. Going to wait to put anything on 9.x until we sort out the regressions.

[asfimport]

Greg Miller (@gsmiller) (migrated from JIRA)

Looks like this change worked! The performance improvement carried over into the nightly benchmarks this time with no regressions (e.g., https://home.apache.org/\~mikemccand/lucenebench/BrowseMonthTaxoFacets.html). So I strongly suspect the issue before (in LUCENE-10350) was changing the for-loop to a while-loop. I suspect the compiler is able to optimize the for-loop construct on the nightly benchmark hardware in a way that it can't with the while-loop (???). I'm going to give this a try (created #11416 to track).

[asfimport]

ASF subversion and git services (migrated from JIRA)

Commit c5c082e in lucene's branch refs/heads/branch_9x from Greg Miller
https://gitbox.apache.org/repos/asf?p=lucene.git;h=c5c082e

LUCENE-10379: Count directly into the dense values array in FastTaxonomyFacetCounts#countAll

Co-authored-by: guofeng.my <guofeng.my@bytedance.com>

[asfimport]

Greg Miller (@gsmiller) (migrated from JIRA)

This has now been backported to 9.x. Resolving.

[asfimport]

Adrien Grand (@jpountz) (migrated from JIRA)

Closing after the 9.1.0 release.