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https://issues.apache.org/jira/browse/CASSANDRA-1632?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13828304#comment-13828304
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Jason Brown commented on CASSANDRA-1632:
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On a happier note, though, by simply switching OTC to batch read from it's LBQ,
I scored a 10% improvement in coordinator throughput (latencies remained
unaffected). I'll clean up that patch
(https://github.com/jasobrown/cassandra/tree/1632_batchDispatch), and actually
put in error handling :). I'll also add the same technique elsewhere in the
code, although PeriodicCommitLogExecutorService seems like the only other
interesting place to apply it.
> Thread workflow and cpu affinity
> --------------------------------
>
> Key: CASSANDRA-1632
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1632
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Chris Goffinet
> Assignee: Jason Brown
> Labels: performance
> Attachments: threadAff_reads.txt, threadAff_writes.txt
>
>
> Here are some thoughts I wanted to write down, we need to run some serious
> benchmarks to see the benefits:
> 1) All thread pools for our stages use a shared queue per stage. For some
> stages we could move to a model where each thread has its own queue. This
> would reduce lock contention on the shared queue. This workload only suits
> the stages that have no variance, else you run into thread starvation. Some
> stages that this might work: ROW-MUTATION.
> 2) Set cpu affinity for each thread in each stage. If we can pin threads to
> specific cores, and control the workflow of a message from Thrift down to
> each stage, we should see improvements on reducing L1 cache misses. We would
> need to build a JNI extension (to set cpu affinity), as I could not find
> anywhere in JDK where it was exposed.
> 3) Batching the delivery of requests across stage boundaries. Peter Schuller
> hasn't looked deep enough yet into the JDK, but he thinks there may be
> significant improvements to be had there. Especially in high-throughput
> situations. If on each consumption you were to consume everything in the
> queue, rather than implying a synchronization point in between each request.
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