recvfrom():how to receive multiple UDP packets.

Hello All,

I am working on a embedded system which should be capable of receiving
UDP packets from
multicasting server sending packets at around 80Mbps. I am losing
packets between the two recvfrom() api calls.
my thread just receives a packet, strip out some of the details and
copy the data to a buffer through memcpy and again go to recvfrom()
call.
This thread works fine at bit rates of around 20Mbps but at 80 Mbps
many packets are
getting lost.
It is very clear that at higher bit rates my user level thread is not
fast enough to cope up with the high rate of incoming packets.
I think since in present condition one call of recvfrom() api would
read only 1 packet from the ethernet incoming buffer rather than
copying all. Now this recvfrom() api is in user space which will take a
longer time to go into the kernel space and returning from there.

So is there a socket API which can receive multiple UDP packets with
one call.

This should help me because in that case i have to call only once from
user space to receive "n" packets rather than "n" recvfrom() calls from
userspace.

Thanks,
Aakash

Do you think your application is too slow to keep-up on a _sustained_
basis or is it perhaps the case that it is only occasionally getting
behind?

If the latter you could try increasing the SO_RCVBUF size with a
setsockopt() call (and perhaps a sysctl to raise the "hard" limit)

What happens to the data you memcpy? Can that work be done using the
buffer(s) you passed to recvfrom()?

rick jones
--
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The real question is "Can it be patched?"
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...