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https://issues.apache.org/jira/browse/CASSANDRA-4718?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13635141#comment-13635141
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Piotr Kołaczkowski edited comment on CASSANDRA-4718 at 4/18/13 2:08 PM:
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-Interesting thing, that after boosting the number of threads that invoke the
process() method from 1 to 16, Akka gets slower, while thread-pool per stage
approach gets faster.-
-16 user threads invoking process(), 4 core i7 with HT (8-virtual cores):-
Huh, Sergio Bossa found a bug in my multithreaded benchmark...
was (Author: pkolaczk):
Interesting thing, that after boosting the number of threads that invoke
the process() method from 1 to 16, Akka gets slower, while thread-pool per
stage approach gets faster.
16 user threads invoking process(), 4 core i7 with HT (8-virtual cores):
{noformat}
2 stages:
Sync: 28195 ns
Async: 26852 ns
Akka: 51651 ns
4 stages:
Sync: 75295 ns
Async: 60381 ns
Akka: 85954 ns
8 stages:
Sync: 176879 ns
Async: 124712 ns
Akka: 103073 ns
16 stages:
Sync: 367728 ns
Async: 259715 ns
Akka: 146875 ns
{noformat}
top reports total ~780% CPU utilisation
thread-pools: ~60% system, ~40% user
Akka: ~15% system, ~85% user
I try to add Disruptor to the benchmark suite.
> 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
> Priority: Minor
> Attachments: baq vs trunk.png, PerThreadQueue.java
>
>
> 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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