CountedBitSet doesn't need to extend BitSet. #28239
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Changing it makes sure that calls to BitSet methods are always bimorphic, which Java can handle more efficiently.
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I think this is maybe guided by a misunderstanding of call-site dispatching in the JVM? The method caches are per call-site, so if a call-site only ever sees one (monomorphic) or two (biomorphic) runtime types then the JVM will use optimized inline caches for method dispatching at that call site. If another call site sees a different collection of runtime types for the same virtual method dispatch, a different inline cache is used, and amongst these call sites there could be more than two runtime types yet the JVM could still used optimized inline caches. It is only when a call site sees more than two (megamorphic) that the call site is not optimized, yet still it does not impact other call sites. |
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Indeed, I don't expect improvements from this patch (hence the |
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@bleskes What do you think? I remember that you preferred to make |
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I originally thought we'd benefit more from this being a BitSet we can pass around. Given how limited this ended up being, I don't really mind either way. It's enough for me that @jpountz wants to do it :) |
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Thanks @dnhatn |
* master: Trim down usages of `ShardOperationFailedException` interface (#28312) Do not return all indices if a specific alias is requested via get aliases api. [Test] Lower bwc version for rank-eval rest tests CountedBitSet doesn't need to extend BitSet. (#28239) Calculate sum in Kahan summation algorithm in aggregations (#27807) (#27848) Remove the `update_all_types` option. (#28288) Add information when master node left to DiscoveryNodes' shortSummary() (#28197) Provide explanation of dangling indices, fixes #26008 (#26999)
* 6.x: Trim down usages of `ShardOperationFailedException` interface (#28312) Clean up commits when global checkpoint advanced (#28140) Do not return all indices if a specific alias is requested via get aliases api. CountedBitSet doesn't need to extend BitSet. (#28239) Calculate sum in Kahan summation algorithm in aggregations (#27807) (#27848)
* master: (94 commits) Completely remove Painless Type from AnalyzerCaster in favor of Java Class. (elastic#28329) Fix spelling error Reindex: Wait for deletion in test Reindex: log more on rare test failure Ensure we protect Collections obtained from scripts from self-referencing (elastic#28335) [Docs] Fix asciidoc style in composite agg docs Adds the ability to specify a format on composite date_histogram source (elastic#28310) Provide a better error message for the case when all shards failed (elastic#28333) [Test] Re-Add integer_range and date_range field types for query builder tests (elastic#28171) Added Put Mapping API to high-level Rest client (elastic#27869) Revert change that does not return all indices if a specific alias is requested via get alias api. (elastic#28294) Painless: Replace Painless Type with Java Class during Casts (elastic#27847) Notify affixMap settings when any under the registered prefix matches (elastic#28317) Trim down usages of `ShardOperationFailedException` interface (elastic#28312) Do not return all indices if a specific alias is requested via get aliases api. [Test] Lower bwc version for rank-eval rest tests CountedBitSet doesn't need to extend BitSet. (elastic#28239) Calculate sum in Kahan summation algorithm in aggregations (elastic#27807) (elastic#27848) Remove the `update_all_types` option. (elastic#28288) Add information when master node left to DiscoveryNodes' shortSummary() (elastic#28197) ...
Changing it makes sure that calls to BitSet methods are always bimorphic, which
Java can handle more efficiently.