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https://issues.apache.org/jira/browse/CASSANDRA-15215?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17437456#comment-17437456
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Benedict Elliott Smith commented on CASSANDRA-15215:
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If we're improving the benchmark we might also want to consider increasing the
morphism of the call sites, i.e. randomly supplying either a
{{DirectByteBuffer}} or {{HeapByteBuffer}}, and maybe even a
{{MappedByteBuffer}} to make it megamorphic; for the {{DataOutput}} variant to
similarly pick two or three variants (preferably with three benchmarks, namely
monomorphic (one type), bimorphic (two types), megamorphic (three types)).
> VIntCoding should read and write more efficiently
> -------------------------------------------------
>
> Key: CASSANDRA-15215
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15215
> Project: Cassandra
> Issue Type: Bug
> Components: Local/Compaction, Local/SSTable
> Reporter: Benedict Elliott Smith
> Assignee: Aleksandr Sorokoumov
> Priority: Normal
> Fix For: 3.0.x, 3.11.x, 4.x
>
>
> Most vints occupy significantly fewer than 8 bytes, and most buffers have >=
> 8 bytes spare, in which case we can construct the relevant bytes in a
> register and memcpy them to the correct position. Since we read and write a
> lot of vints, this waste is probably measurable, particularly during
> compaction and flush, and can probably be considered a performance bug.
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