Jay Shrauner created ZOOKEEPER-1504:
---------------------------------------
Summary: Multi-thread NIOServerCnxn
Key: ZOOKEEPER-1504
URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1504
Project: ZooKeeper
Issue Type: Improvement
Components: server
Reporter: Jay Shrauner
Assignee: Jay Shrauner
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: ExecutorService wrapper that makes worker threads daemon
threads and names then in an easily debuggable manner
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
