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https://issues.apache.org/jira/browse/CASSANDRA-4718?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13996388#comment-13996388
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Benedict commented on CASSANDRA-4718:
-------------------------------------

[~jasobrown] I've updated the repository with a number of minor 
tweaks/refactors, and improved comments. Let me know if there's anything still 
unclear.

> More-efficient ExecutorService for improved throughput
> ------------------------------------------------------
>
>                 Key: CASSANDRA-4718
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-4718
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Jonathan Ellis
>            Assignee: Jason Brown
>            Priority: Minor
>              Labels: performance
>             Fix For: 2.1.0
>
>         Attachments: 4718-v1.patch, PerThreadQueue.java, aws.svg, 
> backpressure-stress.out.txt, baq vs trunk.png, 
> belliotsmith_branches-stress.out.txt, jason_read.svg, jason_read_latency.svg, 
> jason_write.svg, op costs of various queues.ods, stress op rate with various 
> queues.ods, v1-stress.out
>
>
> Currently all our execution stages dequeue tasks one at a time.  This can 
> result in contention between producers and consumers (although we do our best 
> to minimize this by using LinkedBlockingQueue).
> One approach to mitigating this would be to make consumer threads do more 
> work in "bulk" instead of just one task per dequeue.  (Producer threads tend 
> to be single-task oriented by nature, so I don't see an equivalent 
> opportunity there.)
> BlockingQueue has a drainTo(collection, int) method that would be perfect for 
> this.  However, no ExecutorService in the jdk supports using drainTo, nor 
> could I google one.
> What I would like to do here is create just such a beast and wire it into (at 
> least) the write and read stages.  (Other possible candidates for such an 
> optimization, such as the CommitLog and OutboundTCPConnection, are not 
> ExecutorService-based and will need to be one-offs.)
> AbstractExecutorService may be useful.  The implementations of 
> ICommitLogExecutorService may also be useful. (Despite the name these are not 
> actual ExecutorServices, although they share the most important properties of 
> one.)



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