TCP/IP problem : 'Still waiting for mbuf cluster'

[Ian Caddy]

Hi Sylvain,

This is just a guess, but what have you set your mbuf and mbuf cluster 
allocations up as?

We use about 512K for mbufs and the same for mbuf clusters.

    rtems_bsdnet_config.mbuf_bytecount         = 512 * 1024;
    rtems_bsdnet_config.mbuf_cluster_bytecount = 512 * 1024;

It looks like you are running out of room, when you increase your socket 
send buffer size.  Is there any scope for increasing your mbuf and mbuf 
cluster sizes?

regards,

Ian Caddy


Sylvain Prestavoine wrote:
> Hello,
> 
> 
> When I initialize SO_SNDBUF with 5000 ( setsockopt function ), my box can
> send
> TCP packets properly.
> However, with SO_SNDBUF=20000, after some exchange, the TCP  trafic is stop
> and the message 'Still waiting for mbuf cluster' appear.
> 
> The tcp dump tell that problem appear when TCP windows size is too small (
> client side ).
> 
> My question is  : how to obtain a less working without to end up RTEMS fatal
> error ?
> Today, I use a arbitrary value for SNDBUF, but there are no garantee this
> problem
> don't recur.
> 
> Thanks for ideas.
> 
> Sylvain
> 
> [RTEMS-4.6.1, BSP based upon m68k]
> 

-- 
Ian Caddy
Goanna Technologies Pty Ltd
+61 8 9221 1860