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https://issues.apache.org/jira/browse/LUCENE-9403?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17136516#comment-17136516
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ASF subversion and git services commented on LUCENE-9403:
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Commit 4decd5aa9c59c1a64ce43a3182784595636b1273 in lucene-solr's branch
refs/heads/master from Robert Muir
[ https://gitbox.apache.org/repos/asf?p=lucene-solr.git;h=4decd5a ]
LUCENE-9403: tune BufferedChecksum.DEFAULT_BUFFERSIZE
Increase the buffersize used for ChecksumIndexInput for better crc performance.
> tune BufferedChecksum.DEFAULT_BUFFERSIZE
> ----------------------------------------
>
> Key: LUCENE-9403
> URL: https://issues.apache.org/jira/browse/LUCENE-9403
> Project: Lucene - Core
> Issue Type: Improvement
> Reporter: Robert Muir
> Priority: Major
> Attachments: LUCENE-9403.patch
>
>
> This is currently set to 256 bytes, so that's the amount of data we pass to
> crc.update() at once.
> I tried different sizes with https://github.com/benalexau/hash-bench and
> JDK14:
> {noformat}
> HashBench.withArray crc32-jre 256 avgt 5 81.349 ± 8.364
> ns/op
> HashBench.withArray crc32-jre 512 avgt 5 95.204 ± 10.057
> ns/op
> HashBench.withArray crc32-jre 1024 avgt 5 120.081 ± 8.471
> ns/op
> HashBench.withArray crc32-jre 2048 avgt 5 173.505 ± 8.857
> ns/op
> HashBench.withArray crc32-jre 8192 avgt 5 487.721 ± 11.435
> ns/op
> {noformat}
> based on this let's bump the buffersize from 256 to 1024? I think we want to
> avoid huge buffers but still keep the CPU overhead low. It only impacts
> ChecksumIndexInputs (e.g. speed of checkIntegrity() calls at merge) because
> IndexOutputs do not need this buffer.
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