high interrupts by network interfaces

[Brian Candler]

On Sun, Dec 11, 2005 at 03:26:50AM -0800, kamal kc wrote:
> i modified the bridge.c file and added a routine to
> compress/decompress 
> ip packet. i put my code in bdg_forward(). And ran the
> pc in bridge mode.
> 
> The modified kernel is deployed in network where the
> datarate is 
> about 4 to 6 Mbps. One thing to be noted is that the
> pc receives 
> continues data at 4 to 6 Mbps rather than sudden burst
> at intervals.
> 
> Now the problem is, I am getting very high interrupts
> from the network 
> interfaces. the cpu utilization by the interrupts is
> high due to which there
> is latency added to the packets forwarded by the pc.
> The pc attempts to 
> compress/decompress all tcp packets.

Suggestion: start with a standard kernel, without your custom modifications.

If unmodified bridging works, and you get the high interrupt level, then you
have found a problem with in FreeBSD.

If unmodified bridging works, but interrupts are at a normal level, then you
have a found a problem with your own code.