Re: [LARTC] Which CPU for heavy traffic with much filtering/shaping?

[Marek Kierdelewicz <marek@piasta.pl>]

>Hi

Hi

>I have a router with a large number of iptables rules and some
>extensive traffic shaping (HTB + RED + ... ) + conntrack.

Performance boost tips:

- Use "set" module instead of sequential iptables rules. It can lower
cpu usage.

- Use hashing filters for shaping if you're using many u32 filters.

- configure conntrack to use bigger hashsize for better performance;
i'm passing following parameter to kernel in grub to achieve this:
ip_conntrack.hashsize\x1048575 

- configure routecache to use bigger to use more memory for better
performance; i'm passing following parameter to kernel in grub to
achieve this: rhash_entries$00000

>1. What processors should I be looking for in order to achieve the
>best routing throughput on a linux router?

I've had good experiences with P4 (with and without HT), Athlon64, Xeon
[dempsey], Xeon [woodcrest]. The last one is the best choice because of
the large cache and architecture. I think you can use Core 2 Duo too
if you want to save some money.

>2. Is it true that multicore processors will not help much in this 
>situation?

Not true. In your setup with two nics with same load you can easily use
two cores. You can assign each nic to different core by the means of
smp_affinity setting in /proc/irq/... or by using irqbalance daemon.

>Best regards,
>Derek

pozdrawiam
Marek Kierdelewicz
KoBa ISP
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