Hi Wijnand,

Having fun @ HAR? :)

On Thu, Aug 13, 2009 at 11:19:27AM +0200, Wijnand Wiersma wrote:
quoted text
> Hi,
>
> I am using a machine with only a 500Mhz VIA cpu as NAT/IPSEC gateway  
> here at the har2009.org camp.
> Sometimes the internet is hardly usable, loadavg spikes up to  14. When 
> investigating I see 80-90% of the CPU time is because of interupts.
> Almost all interrupts  are for the rl0 and rl1 interface.
>
> The interrupt load is not coupled to bandwith usage, we can use 60Mbit  
> without any problems.
> I know rl(4) cards are crappy but I am wondering what could cause these 
> strange spikes?
> It must be because of packets per second, but I can't find a offender.  
> Are there any tweaks to mitigate the effects?
>
> Right after the load spikes (normally these last for 15 minutes) the  
> IPSEC tunnels are not in a usable state anymore.
> Does anyone have a workaround for this?

You could try using polling(4) for the rl cards.  This could ease
interrupts a bit.

Kind regards

Robert Blacquiere