> From: Michael Ludwig [mailto:mil...@gmx.de] > Subject: Re: (Tomcat) Does NIO connector make a difference outside of 'Comet' > ?
> can we say that: > (a) blocking IO requires one thread (or, in some other > server environments, one process) per socket Well, sort of. The actual requirement is one thread per established HTTP connection, where a connection is typically done using sockets. There's no switching overhead until traffic arrives on the connection, and the waiting thread is activated to process it. Otherwise, the thread is stalled until either input arrives or a timeout occurs. > (b) non-blocking IO allows a thread or process to switch > between sockets, thus providing scheduling and concurrency > on just another level, possibly with advantages? Again, kind of. There's one thread that polls the connections for traffic, and when something arrives, it passes the connection off to a request handler to do something useful with it. When the request handling is finished, the worker thread goes back to the pool, and control of the connection is relinquished to the polling thread. Consequently, you only need as many threads as there are active requests, as opposed to needing one per active (and usually idle) connection. I suspect you'd be hard pressed to measure any switching difference between the two (NIO may actually be slightly worse); the main advantage of NIO is that fewer resources (threads) are tied up doing nothing while waiting for clients to send something. - Chuck THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
