On Wed, Feb 23, 2011 at 06:07:16PM +0100, Patrick Lamaiziere wrote:
> I log the congestion counter (each 10s) and there are at max 3 or 4
> congestions per day. I don't think the bottleneck is pf.

The congestion counter doesn't directly mean you have a bottleneck in
PF; it's triggered by the IP input queue being full, and could indicate
a bottleneck in other places as well, which PF tries to help out with by
dropping packets earlier.


> > Interface errors?
> 
> Quite a lot.

The output of `systat mbufs` is worth looking at, in particular the
figure for LIVELOCKS, and the LWM/CWM figures for the interface(s) in
question. 

If the livelocks value is very high, and the LWM/CWM numbers are very
small, it is likely that the MCLGETI interface is protecting your system
from being completly flattened by forcing the em card to drop packets
(supported by your statement that the error rate is high). If it's bad
enough MCLGETI will be so effective that the pf congestion counter will
not get increment.


You mentioned the following in your initial email:

> #define MAX_INTS_PER_SEC        8000
>
> Do you think I can increase this value? The interrupt rate of the
> machine is at max ~60% (top).

Increasing this value will likely hurt you. 60% interrupt rate sounds
about right to me for a firewall system that is running at full tilt;
100% interrupt is very bad, if your system spends all cycles servicing
interrupts it will not do very much of anything useful.


>dmesg:
> em0 at pci5 dev 0 function 0 "Intel PRO/1000 QP (82571EB)" rev
> 0x06: apic 1 int 13 (irq 14), address 00:15:17:ed:98:9d
>
> em4 at pci9 dev 0 function 0 "Intel PRO/1000 QP (82575GB)" rev 0x02:
> apic 1 int 23 (irq 11), address 00:1b:21:38:e0:80

How about a _full_ dmesg, so someone can take a wild guess at what
your machine is capable of?

-Ryan

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