[
https://issues.apache.org/jira/browse/CASSANDRA-4718?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Jason Brown updated CASSANDRA-4718:
-----------------------------------
Attachment: backpressure-stress.out.txt
I've run both of [~benedict]'s patches on my test cluster, and the results are
quite hopeful (see backpressure-stress.out). Short story is anything we do for
the native protocol will at least double the throughput and halve the latency,
but that's the low end of the improvements.
Benedict's second patch is about 5-10% faster than his first, and both are
slightly slower than my original patch. As I think it's important to have back
pressure for any pool, at a minimum I think we should go with [~benedict]'s
first patch. I like the ideas in the second patch, but would like another day
to digest the implementation.
> 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,
> backpressure-stress.out.txt, 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.)
--
This message was sent by Atlassian JIRA
(v6.2#6252)
