Server Implementation Blocking-Socket Question

[k3xji]

Hi all,

I am trying to implement a Game Server which will serve 0-5000 clients
at a time. I am thinking to implement it in Python for to develop it
faster.

After days of reviewing different design approaches, I came up with
the following:

- Sockets are blocking, and we WILL have only one SOCKET connection to
client.
- Each client's request is processed in a separate thread.
- When a client requests something, the request is put in the JobQueue
of another thread. And this thread is responsible to process it.(This
is a MUST, I do not want to rely on the client thread itself to
process the Job)Here is my question arise.

As we have only one connection to the client, it is possible to have
THREAD A called socket.recv() and at the same time THREAD B called
socket.send().

Is it safe use send()/recv() simultaneously from different threads for
the same socket. And please note that addiion to THREAD A and B there
is a high chance that THREAD C might call socket.send() which makes
multiple call to recv()/send()/send() on the same socket.

Is multiple thread/one socket is not a reliable method for these
situation, which IS? And, why?
Different design suggestions?

Thanks all.

[Barry Margolin]

In article
<ba328cdb-d94f-486c...@e53g2000hsa.googlegroups.com>,
k3xji <sum...@gmail.com> wrote:

> Hi all,
>
> I am trying to implement a Game Server which will serve 0-5000 clients
> at a time. I am thinking to implement it in Python for to develop it
> faster.
>
> After days of reviewing different design approaches, I came up with
> the following:
>
> - Sockets are blocking, and we WILL have only one SOCKET connection to
> client.
> - Each client's request is processed in a separate thread.
> - When a client requests something, the request is put in the JobQueue
> of another thread. And this thread is responsible to process it.(This
> is a MUST, I do not want to rely on the client thread itself to
> process the Job)Here is my question arise.
>
>
> As we have only one connection to the client, it is possible to have
> THREAD A called socket.recv() and at the same time THREAD B called
> socket.send().
>
> Is it safe use send()/recv() simultaneously from different threads for
> the same socket. And please note that addiion to THREAD A and B there
> is a high chance that THREAD C might call socket.send() which makes
> multiple call to recv()/send()/send() on the same socket.

It's definitely safe to call send() and recv() simultaneously. The two
directions of a socket are totally independent, except that they get
opened and closed together.

Two threads both calling socket.send() concurrently might not be so
safe, if this calls the underlying send() multiple times. This is
because their send() calls might get interleaved. You'll need to use a
mutex to serialize them.

> Is multiple thread/one socket is not a reliable method for these
> situation, which IS? And, why?
> Different design suggestions?
>
> Thanks all.

--
Barry Margolin, bar...@alum.mit.edu
Arlington, MA
*** PLEASE don't copy me on replies, I'll read them in the group ***