Re: Linux based router for Gigabit traffic

["Stephen J. Smoogen" <smooge@gmail.com>]

On Sun, 22 Aug 2004 23:55:29 +0530, Anantha Kiran
<ananth.kandukuri@gmail.com> wrote:
> No, we are not using NAPI for this. But we wrote a net_hook module
> which catches the pkts before allowing it to go upper layers.
> 
> CPU utilization is 70+ while dropping.
> 
> Can u tell me the configuration of your low-end machine.Like PCI-bus,
> and others.
> 

Ours are Intel(R) Xeon(TM) CPU 2.40GHz and the motherboard has a PCI-X
chipset on it. We have one Intel fibre optic Gig-E on the 02:01 PCI-X
Bus, and the other on the 03:01 PCI-X bus. I see a limit of about 750
mbits/sec on a fixed load (HTTP accesses for specific boxes), and 400
mbits/sec on a mixed load (ICMP/UDP/TCP). In each case, the maximum
looks to not be the bus speed as much as the soft-irq limit (which is
what mpstat says is using all the resources). The number of packets
per second that ifconfig and other tools gives me looks about the
same. so I am thinking it isnt bus width at the moment as much as
IRQ/packets per second.

The kernels are NAPI compiled.. but I really havent figure out if
using netfilters on these mixed loads 'disables' it.

-- 
Stephen J Smoogen.
Professional System Administrator