[lwip-users] Transferring large data fast and pointing pbufs directly to Ethernet receive buffers

[Bill Auerbach]

Hello group,

 

I’m implementing GBE (gigabit Ethernet) on a PowerPC platform and because of realtime constraints chose lwIP with no OS.  I need to receive 1MB-4MB images as fast as possible for some processing and then will be passing them on to other hardware.  Is MEMP_NUM_TCPIP_MSG the significant parameter to change to be able to buffer the entire image while it’s being processed serially and passed on?

 

Secondly, the PowerPC loads packets directly into buffer descriptor memory.  Is looks possible (best) at low_level_input to point pbufs right into the received packet without copying.  If I’m correct that this can be done, the question I have is, where can I know the data was read by the upper layer to be able free the pbuf and at the same time to be able to free memory for the Ethernet controller?

 

Thank you,

 

Bill Auerbach