RE: [lwip-users] PPP negotiation frame length and sio_read() inco mpatibility

[Wilson, Clive]

Guille,

Just a quick question regarding your sio_read strategy you mentioned below - what were the relative priorities for the threads in your system? I have pppMain at the highest priority level, with the consuming thread (tcpip_thread in my case) at a lower priority along with the application thread. Is this your configuration, or do you have it different?

Does anyone else have an angle on this?

Thanks again in anticipation,

Clive Wilson

> -----Original Message-----
> From: Guillermo Prandi [mailto:address@hidden]
> Sent: 17 May 2006 15:01
> To: 'Mailing list for lwIP users'
> Subject: RE: [lwip-users] PPP negotiation frame length and
> sio_read() inco mpatibility
>
> Wilson, you should block for at least one character in order
> to avoid excesive CPU usage (which will of course slow down
> everything).
> 
> I only had to modify ppp.c:sifup() in order to make it work
> up to the UDP level (I haven't tested TCP). Read my other
> mail regarding bug #16602 for details. Otherwise,
> implementation was very straightforward.
> 
> Guille
> 
> -----Original Message-----
> From: Wilson, Clive [mailto:address@hidden]
> Sent: Wednesday, May 17, 2006 10:50
> To: 'Mailing list for lwIP users'
> Subject: RE: [lwip-users] PPP negotiation frame length and
> sio_read() inco mpatibility
>
>
>
> Guille,
>
> Thanks for your reply. Actually, this morning I took a fresh
> look at the PPP code and realised that the only way the
> sio_read() call in pppMain() could possibly work was if it
> was non blocking. So I changed my implementation of
> sio_read() so that it returns immediately, irrespective of
> how much data it has retrieved. The good news is that an LCP
> dialogue of sorts is happening - however, the peers get as
> far as agreeing the Auth type, then the process repeats with
> the original ID number again. Ultimately one end gives up and
> the process fails. I also find that throughput is very slow -
> this may be the reason for the above problem?
>
> Did you find you had to change any PPP code (LCP, Auth, IPCP
> etc) in order to get the whole thing working? I'm not at all
> confident that the PPP code as shipped will work OK - I
> figure that very few people are actively using it. Either
> that or their not prepared to merge their findings into the
> current LwIP development 8-)
>
> Bye for now,
>
> CTW
>
> > -----Original Message-----
> > From: Guillermo Prandi [mailto:address@hidden]
> > Sent: 17 May 2006 14:35
> > To: 'address@hidden'
> > Subject: RE: [lwip-users] PPP negotiation frame length and
> > sio_read() inco mpatibility
> >
> > Hi, Wilson. I got it working in my Windows test
> implementation by not
> > returning unless at least one byte was read. >From the
> source code I
> > interpreted that sio_read should return AT MOST the specified
> > number of
> > characters. Additionally, Windows lets you specify an
> inter-character
> > timeout for the read operation, so you can keep reading if
> > more characters
> > keep coming and thus reduce the processing overhead. You
> > could implement
> > something alike (some UARTs implement such timeout too).
> >
> > Guille
> >
> >
> > _______________________________________________
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> > http://lists.nongnu.org/mailman/listinfo/lwip-users
> >
>
>