no, it's much faster and more efficent to do overlapped (async) io and then
hand the completed io over to a thread in the thread pool. no point keeping
thousands of threads around if they're going to be blocked anyway. let them
do some real work.
peter
----- Original Message -----
From: "Jim Bailey" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, August 31, 2000 11:32 PM
Subject: Re: highly scalable network server app
> That's an interesting technique. Is it actually faster to do non-blocking
io
> and scan for results over thousands of threads rather than have the OS do
> the blocking? It seems hard for me to believe that the OS isn't doing IO
> better than most C programmers but maybe I'm being naive.
>
> Also, do you know what the problem is for a JVM to block a few thousand IO
> threads? Is it that the priority scheme in Java is a little flakey and
> little under-specified? I haven't had to do that kind of scaling so it is
a
> very interesting question to me. I would have guessed that modern JVMs
> running on robust OS's like NT and Unix using native threads through the
JDK
> would be fine with a large number of threads. Also, doesn't using a
multiple
> processor box help with this problem?
>
> Thoughts and feedback are greatly appreciated.
>
> -----Original Message-----
> From: Ken X Horn [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, August 31, 2000 6:27 AM
> To: [EMAIL PROTECTED]
> Subject: Re: highly scalable network server app
>
>
> One problem you may encounter with java is the (current) lack of
> non-blocking
> i/o . This means that for every connection, you need a thread running,
> because
> you can't loop across the open sockets and check for waiting data, like
you
> can
> in C. Most JVM's don't scale well into the 1000's of threads so this will
> hurt
> -- though I think possibly TowerJ and a couple of other JVM's are good at
> this
> (IBM claim the OS/390 one won't even blink at this stuff - if you've got
one
> handy ;o) . JDK 1.4 i think will have the new I/O APIs. It'll be a while
> before
> you can use that though.
>
> I seem to remember HP implemented a select() call of sorts in order to
cope
> with
> this at one point.
>
> Ken.
>
>
>
>
>
> [EMAIL PROTECTED] on 30/08/2000 15:39:38
>
> Please respond to [EMAIL PROTECTED]
>
> To: [EMAIL PROTECTED]
> cc: (bcc: Ken X Horn)
> Subject: Re: highly scalable network server app
>
>
>
>
> You will need much more memory than with the C++ model but that is
> practically free. I suspect that you will also need a faster processor,
but
> again, who cares? The cost of deployment is hardly impacted by the cost of
a
> server in most cases in my experience. You are going to want to write a
lot
> of code to do pooling of resources and pay special attention to memory
> management but Java makes that relatively easy as well.
>
> I believe that if you can do it with C++ then you can do the same scaling
> with a little work with Java. And you get tremendous benefits as well.
Java
> is much more maintainable than C++. Porting to a new platform ought to be
> trivial. You get the benefits of very well designed API's like JDBC and
the
> Java 2 collection classes.
>
>
> -----Original Message-----
> From: skeptical [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, August 30, 2000 1:07 PM
> To: [EMAIL PROTECTED]
> Subject: Re: highly scalable network server app
>
>
> corey:
>
> thanks for your info. just another note on nt. first of all, i'm not a
msft
> fan. and i also love the concept of java's write once run anywhere. my
> impression is that it's not very scalable. i'll tell you my experience and
> you can tell me what you think. my company recently wrote a client server
> app. we wrote the app server which services about 10k tcp connections with
> incoming requests for a sql server. we used i/o completion port such that
> socket i/o is very efficient. the machine we use is a single celeron 500
> with 256mb ram, running windows 2000 advanced server. under our stress
test
> with 10k users, we are not hitting any bottlenecks. my question is: if i
> were to do this with java, 1. how will i write the code? 2. what hardware
do
> i need in order to achieve the same performance?
>
> tks,
> peter
>
> ----- Original Message -----
> From: "Corey A. Johnson" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Thursday, August 31, 2000 1:36 AM
> Subject: Re: highly scalable network server app
>
>
> > Just to comment... i used Sybase Jaguar CTS servers in a recent project
> > i did for a very large client... using two Solaris servers...
> > clustered... And they are easily handling 1000 simultaneous EJB
> > connections each....
> >
> > Cj
> >
>
>
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