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Posted to issues@ignite.apache.org by "Vladimir Ozerov (JIRA)" <ji...@apache.org> on 2016/01/26 15:15:39 UTC
[jira] [Commented] (IGNITE-2408) Hot spot in
GridDhtAtomicCache$DeferredResponseBuffer.addResponse()
[ https://issues.apache.org/jira/browse/IGNITE-2408?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15117252#comment-15117252 ]
Vladimir Ozerov commented on IGNITE-2408:
-----------------------------------------
The problem can be reproduced as follows:
1) ATOMIC cache in PRIMARY_SYNC mode;
2) One backup;
3) Start two nodes on a local host;
4) Run put operations from several threads.
> Hot spot in GridDhtAtomicCache$DeferredResponseBuffer.addResponse()
> -------------------------------------------------------------------
>
> Key: IGNITE-2408
> URL: https://issues.apache.org/jira/browse/IGNITE-2408
> Project: Ignite
> Issue Type: Sub-task
> Components: cache
> Affects Versions: 1.5.0.final
> Reporter: Vladimir Ozerov
> Assignee: Ilya Lantukh
> Priority: Critical
> Fix For: 1.6
>
>
> Problems:
> 1) DeferredResponseBuffer.respVers is ConcurrentLinkedDeque8 and size() method is called on it. It is O(N) for this collection, hence the hot spot.
> 2) We use read-write lock for very small updates. This is not efficient.
> Probably we should simply switch to (sycnhronized + ArrayList) and this will be enough.
> If synchronized is not an option, at the very least we must use collection with O(1) size or maintain separate counter (e.g. LongAccumulator).
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