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

[Derek Sims <derek@interdart.co.uk>]

Marek Kierdelewicz wrote:
>> 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.
>   

Hmm - I don't know what the "set" module is - can you point me to some 
documentation please?
> - Use hashing filters for shaping if you're using many u32 filters.
>   
Only 3
> - 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 
>
>   
I have 64k in conntrack_max and hashsize of 16000
Currently running with about 20000 conntrack connections

I will try increasing this
> - 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.
>
>   
Thanks - I will see what I can get
>> 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.
>
>   
That is good news :) - however I guess 4 core with dual ethernet would 
not help very much!
>> Best regards,
>> Derek
>>     
>
> pozdrawiam
> Marek Kierdelewicz
> KoBa ISP
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>   
Best regards,
Derek
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