[nanomsg] Re: where could get the detail design docment ?
- From: Martin Sustrik <sustrik@xxxxxxxxxx>
- To: nanomsg@xxxxxxxxxxxxx
- Date: Fri, 17 May 2013 18:52:03 +0200
Hi Yuanzhi,
I wanna know how to find the design document which could tell:
The project is in early stage so there are no detailed design documents.
There are few relevant blog posts here: 250bpm.com/blog though.
1. the workflow
how the data encapsulate and send to the wire?
nn_send (socket, buffer, buffer_size, flags);
see nn_send(3) manual page
2. the communication shceme
is the socket synchronous or asynchronous?
It's asynchronous, i.e. when nn_send() exits it means the message was
sent, not that it was received by the peer.
3. the transport msg format
+---+----+-------+----------
| tag| size | etc ... | payload...
+---+----+-------+----------
I guess you are asking about TCP transport:
8 byte protocol header followed by messages. Each message starts with 8
byte size in network byte order followed by the payload.
On top of that, there's a messaging-pattern specific protocol (pub/sub,
req/rep etc.)
4. the memory management
will the lib cause memery fragmentation, how large of payload could the
lib send, is there a memory pool, could user custom there own memory
management?
and so on.
Every program causes some amount of memory fragmentation.
You can send anything that fits into memory.
There's no nanomsg-specific memory pool. It relies on C runtime/OS to
pool the memory.
If you want to use custom memory allocation, just use an alternative
implementation of malloc/free/realloc in the way similar to tcmalloc,
jemalloc etc. Alternatively you can patch src/utils/alloc.c file and add
your memory allocation routines there.
and also i've got an explicit question on REQREP
Dose the REQREP support asynchronous msg? I wanna send many request
through the same socket at the same time in a message loop, and when
replies come back i should deal with it and find the related request.
eg.
switch (event)
{
case event_req:
send_req();
append_req_to_list();
break;
case event_reply:
req = get_req_by_reply_from_list(reply);
process(req, reply);
break;
}
You can do that using raw REQ and REP sockets. Use AF_SP_RAW address
family when creating the sockets.
Martin
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