On Fri, Jan 16, 2009 at 04:43:43PM -0500, Wilson Talaugon wrote:
> Hi,
> 
> We ported TIPC (Transparent Inter-Process Communication) to QNX.  Everything was working fine until we hit the TIPC 
link up/down issue.  TIPC maintains link heartbeat at 2 pkts/s from one node to the other and vice-versa over ethernet 
link.  For some reason we're getting TIPC link down whenever our application sends out a burst of TCP pkts over the same
 ethernet link.  Our tcpdump shows that when the burst of TCP pkts happening none of the TIPC pkts are getting through. 
 We also noticed that after the burst of TCP pkts we started seeing a burst of TIPC pkts.  Looks like the TIPC pkts are 
getting starved and queued somewhere in io-pkt for later transmission.  Is there any way to prioritize pkts in io-pkt.  
I read about setting the priority but you can only set the priority for the driver threads and the option to set 
priority per interface.  The problem is both TCP and TIPC are using the same ethernet link.  Does io-pkt support QOS or 
pkt prioritization?  I read about pfctl but the documentation is not quite clear how to prioritize certain ethernet 
frame since TIPC doesn't use TCP/IP stack and it sends directly to the ethernet driver.

I you aren't using the stack you must be using a dedicated thread?
If so it's probably just a matter of scheduling priorities.  The
stack will float to the priority of the sender when handling messages.
Then there's the incoming packet processing priority you've mentioned
above.

-seanb