Re: Java NIO: calling selector.select() before socketChannel.write()

No. You should only need one selector for your whole app assuming everything
else is CPU bound and you're only targeting one core.

Bob

On Wed, Apr 16, 2008 at 4:18 PM, Sergey Marakhov <[email protected]>
wrote:

> Ok, what do you think about another question: is there any need to
> open/create separate selectors for reading and writing operations? Or even
> more: opening a separate write selector per client connection?
>
> Thank you,
>
> Sergey Marakhov
>
> Phone: (613) 9811 8083
>
> Quest Software
>
>
> -----Original Message-----
> From: Discussion of advanced Java topics. [mailto:
> [email protected]] On Behalf Of Bob Lee
> Sent: Thursday, April 17, 2008 1:04 AM
> To: [email protected]
> Subject: Re: [ADVANCED-JAVA] Java NIO: calling selector.select() before
> socketChannel.write()
>
> Yeah, you use a selector when you want to deal with multiple streams from
> a
> single thread, the idea being that threads don't scale well enough to
> support tens of thousands of connections. TheServerSide recently had an
> article that claimed that thread impls have gotten efficient enough that
> you
> may be better off using blocking I/O. I would test it.
>
> Bob
>
> On Wed, Apr 16, 2008 at 12:22 AM, Avinash Lakshman <[email protected]
> >
> wrote:
>
> > There is no reason to do a select() before a write(). However when you
> do
> > perform a write() you may not write the entire set of bytes you want to
> > write. In that event you want to register for OP_WRITE interest with the
> > selector and when notified by the selector (when the socket is
> writeable)
> > push the remaining bytes out.
> >
> > Cheers
> > A> Date: Tue, 15 Apr 2008 16:48:50 -0700> From: [email protected]>
> > Subject: Re: [ADVANCED-JAVA] Java NIO: calling selector.select() before
> > socketChannel.write()> To: [email protected]> > I've
> never
> > used Java's non-blocking I/O, but in POSIX non-blocking I/O, you>
> typically
> > use one select() for everything.> > Bob> > On Tue, Apr 15, 2008 at 4:27
> PM,
> > Sergey Marakhov <[email protected]>> wrote:> > > Hi all.> >> >
> I'm
> > looking at ways to simplify our current implementation of socket> >
> > communications between an agent and multiple clients. There is a client>
> >
> > connection object created per connected client, client connection is> >
> > passed through an "incoming" selector and each client connection opens
> its>
> > > own outgoing selector. So, question 1: do I need to create separate> >
> > outgoing selectors, or is using a single selector for both in and out> >
> > operations is the way to go?> >> > Next, before each invocation of
> > socketChannel.write(...) method, we do> > outgoingSelector.select(). Is
> it
> > necessary to do select() before write> > operations?> >> > Our knowledge
> of
> > NIO is rather limited, hence all this questions.> >> > Much
> appreciated...> >
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