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Posted to dev@zookeeper.apache.org by "Patrick Hunt (JIRA)" <ji...@apache.org> on 2012/12/08 02:29:21 UTC
[jira] [Updated] (ZOOKEEPER-1504) Multi-thread NIOServerCnxn
[ https://issues.apache.org/jira/browse/ZOOKEEPER-1504?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Patrick Hunt updated ZOOKEEPER-1504:
------------------------------------
Attachment: ZOOKEEPER-1504.patch
Updated the patch to apply cleanly after ZOOKEEPER-1505. Otherwise no other changes.
> Multi-thread NIOServerCnxn
> --------------------------
>
> Key: ZOOKEEPER-1504
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1504
> Project: ZooKeeper
> Issue Type: Improvement
> Components: server
> Affects Versions: 3.4.3, 3.4.4, 3.5.0
> Reporter: Jay Shrauner
> Assignee: Jay Shrauner
> Labels: performance, scaling
> Fix For: 3.5.0
>
> Attachments: ZOOKEEPER-1504.patch, ZOOKEEPER-1504.patch, ZOOKEEPER-1504.patch, ZOOKEEPER-1504.patch, ZOOKEEPER-1504.patch
>
>
> NIOServerCnxnFactory is single threaded, which doesn't scale well to large numbers of clients. This is particularly noticeable when thousands of clients connect. I propose multi-threading this code as follows:
> - 1 acceptor thread, for accepting new connections
> - 1-N selector threads
> - 0-M I/O worker threads
> Numbers of threads are configurable, with defaults scaling according to number of cores. Communication with the selector threads is handled via LinkedBlockingQueues, and connections are permanently assigned to a particular selector thread so that all potentially blocking SelectionKey operations can be performed solely by the selector thread. An ExecutorService is used for the worker threads.
> On a 32 core machine running Linux 2.6.38, achieved best performance with 4 selector threads and 64 worker threads for a 70% +/- 5% improvement in throughput.
> This patch incorporates and supersedes the patches for
> https://issues.apache.org/jira/browse/ZOOKEEPER-517
> https://issues.apache.org/jira/browse/ZOOKEEPER-1444
> New classes introduced in this patch are:
> - ExpiryQueue (from ZOOKEEPER-1444): factor out the logic from SessionTrackerImpl used to expire sessions so that the same logic can be used to expire connections
> - RateLogger (from ZOOKEEPER-517): rate limit error message logging, currently only used to throttle rate of logging "out of file descriptors" errors
> - WorkerService (also in ZOOKEEPER-1505): ExecutorService wrapper that makes worker threads daemon threads and names then in an easily debuggable manner. Supports assignable threads (as used by CommitProcessor) and non-assignable threads (as used here).
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