Re: [lwip-users] Picking appropriate sizes for the different mboxes

[Simon Goldschmidt]

Mason <address@hidden> wrote:
> > On my platform, the Ethernet driver manages a queue of incoming
> > frames (there can be max RX_BUF_COUNT outstanding frames).
> > Typically, RX_BUF_COUNT is between 100 and 200.
> > 
> > Should TCPIP_MBOX_SIZE have a simple relation to RX_BUF_COUNT?

I could imagine setting TCPIP_MBOX_SIZE to "Number of API tasks" + RX_BUF_COUNT 
then. On the other hand, some of the RX_BUF_COUNT buffers will probably be 
buffere *after* being passed to tcpip_thread (by applications or by TCP OOS 
buffer), so setting TCPIP_MBOX_SIZE that high is probably not necessary. Keep 
in mind also that you need enough items in MEMP_TCPIP_MSG_INPKT.

> > The packets queued in TCPIP_MBOX are subsequently dispatched to
> > the appropriate {UDP,TCP}_RECVMBOX?

Not necessarily. They are not queued when they are not passed to a netconn or 
socket (i.e. using the raw (callback) API or packet is dropped).

> > If the RAW API is disabled, DEFAULT_RAW_RECVMBOX_SIZE can be 0, right?

Don't confuse the raw (callback) API with raw netconns/sockets! The latter 
indicates a connection doesn't use UDP/TCP but its own transport-layer protocol.

> > Is there a wiki, or text document covering this material?

Hmm, I don't know, but contributing documentation is always welcome!


> For this error, one can
> #define MEMP_NUM_SYS_TIMEOUT 5
> in lwipopts.h
> 
> Perhaps the default value should be raised?
> Or is this the desired outcome?

I've just fixed the checks that they are not executed when MEMP uses MEM.

Simon
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