[ http://issues.apache.org/jira/browse/DIRMINA-119?page=comments#action_12359023 ]
dave irving commented on DIRMINA-119: ------------------------------------- Yes, that is a good and logical solution. I did think a while back that keeping the threading at the io processor level might be a good way to go (see 4th post above). And infact, the refactoring which has been done for 0.9 such that SocketIoProcessor isn't a singleton anymore makes it much easier. Drawbacks..... The only drawback I can see is that in many systems it is most efficient to have a single pool of selector loops driving the whole IO system (as the number of threads is tied to the number of CPUs). Going this route would mean we'd have a bunch of threads for connectors and a bunch of threads for acceptors. Its not a huge problem though - just means we get slightly more context switching than we really need. The other way round would be to change SocketSessionManager to just have a setter for a ProcessorFactory or something (as in 4th post above). That way we can use the same pool across the whole of mina (acceptors and connectors) - and we dont get any code duplication as the factory does the round-robining instead of the acceptor / connector delegates. > Multiple selector loops > ----------------------- > > Key: DIRMINA-119 > URL: http://issues.apache.org/jira/browse/DIRMINA-119 > Project: Directory MINA > Type: Improvement > Versions: 0.8 > Environment: All. Benefit is dependant on environment > Reporter: dave irving > Assignee: Trustin Lee > Priority: Minor > Fix For: 0.9 > Attachments: prototype.zip > > Mina's SocketIoProcessor currently owns a Selector and employs a single > Worker to run the NIO "selector loop". > I have been running tests where Im trying to maximise throughput and have > found - that in certain multi-cpu environments - this worker thread can > encounter a large amount of starvation even though CPU usage is fairly low. > By testing 2 selector-loops instead of 1, I managed to improve my overall > test throughput by just under 30%. > The general idea is to do this: > - Each SocketIoProcessor.Worker encapsulates its own work queues associated > Selector > - It should be possible to configure the number of Workers (and thus > selectors) employed by SocketIoProcessor > - When a SocketSession is added to the SocketIoProcessor, a Worker is > selected (round-robin) which will be associated with the SocketSession for > its lifetime. This association is managed by SocketSession (get/setWorker) > - When someone asks SocketIoProcessor to do some work to a session, instead > of doing it directly, the processor now asks the session for its Worker, and > delegates to the worker (i.e, the same worker is always used for an > individual session) > I've done some prototyping, and have also checked that the concept works with > the latest build. > The prototype is very hacky - mainly because there are some refactoring > issues i'd like feed-back on before I submit a "proper" patch for review. > Namely: > - How do you want me to tell the SocketIoProcessor how many workers to use? > One option is a system property - but thats pretty hacky. I dont think we > need to support changing the number of workers after operation has begun > (It'll probably be a function of the number of available CPUs) - and this > makes the code simpler. However, as SocketIoProcessor is a (non lazy created) > singleton, we need a way to get the param in. We could refactor, or maybe > introduce a ProcessorOptions class or something. The SocketIoProcessor could > interrigate this when initializing. Any direction on your desired approach > would be appreciated > Cheers, > Dave -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
