[lwip-users] RE: is this a reentrancy problem with LWIP ver

[shogun]

On 3 Sep 2010, at 23:49, shogun wrote:

> Can someone tell me if this is a reentrancy issue?  If I send data too
fast
> on a socket and the stack is still sending the data and I make another
call
> to send more data, will that cause a problem?

It's not clear from your email what the problem you're seeing is.  What
behaviour do you expect?  Is it just that the performance is lower than
you're hoping?  If you send faster than lwIP can get packets onto the
network then getting a memory error after a few sends is what I'd expect.
You just need to try again later.  There shouldn't be any re-entrancy
issues.

Kieran


------------------------------

Your assumption is correct about the performance it less than I expected.
Sending a data block 2894 bytes every 200mS is 14.5kBytes/sec and it works
at that rate.  It appears the fastest I can send that block of data is about
every 100mS and that is about 28.9k Bytes per second.  If I try to send the
2894 byte block every 90mS the send starts failing after 3-4 sends and the
send returns an out of memory error.  At 90mS, that is only 25.7kBytes/sec.
These rates should be easy for a 10MBit connection and I am running a
100MBit connection.  I know the CPU can affect the performance but I am
running a 32 bit arm Cortex M# at 80MHz.  Is this typical performance from
lwip on a TCPIP connection?  


On another note, what do I have to be careful of in regards to lwip not
being reentrant?

Thank you for your help.

DB