On Wed, Mar 04, 2009 at 01:20:42PM -0500, dave allamby wrote:
> Doing an MPEG TS monitor program...Using QNX 4.25 and TCP 5.0
> Hitting the limits of TCP, me thinks,  box has to process a  2 multicast 
> streams of  1340 byte UDP/RTP  every .2 ms for each channel.
> Can process up to about 12000 messages / second just fine (4 multicast 
> sockets/2 channels). After that, messages start getting dropped.
> 
> Even reducing to 1 streams still results in issue (sending 20 packets 
> every 3 ms) results in problem.
> 
> It does appear that Tcpip has some finite limit of packets it will queue 
> onto socket for processing...
> 
> Any insight on what Tcpip does ?

Try increasing the SO_SNDBUF socket option (setsockopt()).  Check
'netstat -pip', 'netstat -pudp'.

-seanb