[jira] [Comment Edited] (CASSANDRA-4718) More-efficient ExecutorService for improved throughput

["Benedict (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-4718?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13968609#comment-13968609 ] 

Benedict edited comment on CASSANDRA-4718 at 4/14/14 6:15 PM:
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Nice! I wonder if this is a much bigger impact on multi-cpu machines, as I did not see anything like this dramatic improvement. But this is great. -Do you have some stress dumps we can look at?- Nevermind, I see that you do :-)

bq. new 2.1 stress seems broken on reads

Shouldn't be - what problem are you seeing?


was (Author: benedict):
Nice! I wonder if this is a much bigger impact on multi-cpu machines, as I did not see anything like this dramatic improvement. But this is great. Do you have some stress dumps we can look at?

bq. new 2.1 stress seems broken on reads

Shouldn't be - what problem are you seeing?

> 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
>
>         Attachments: 4718-v1.patch, PerThreadQueue.java, baq vs trunk.png, 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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