throughput and interrupts

[Tofik Suleymanov]

Bachilo Dmitry wrote:
> Hello.
> I am completely stuck. I have a router, that rules three subnets. At first 
> there were Allied Telesyn's netcards with realtek chipsets. I am using 
> ipfw+natd and I had like 3,5 megabytes per second with 20 per cent of 
> interrupt load. I had "discarded oversized frame" too often so I've replaced 
> two main cards with 3Com 905 and now my xl0 and xl1 never discard frames. But 
> I saw no speed boost and interrupts were also very high. I have discovered 
> some IRQ conflicts and removed them, now I have single device per IRQ, but 
> still i have near 20-30 % of interrupt load, when i download something 
> through this router (and natd takes rest % of CPU). Some people advised me to 
> use polling, so I've built kernel with HZ=1000, polling and tried it. 
> Interrupts grew to 40-50% and speed decreased to 200-300 kb/s, so I had to 
> turn the polling off.
>
> I just don't know what to try, to gain at least 9 mb/s, because this is what I 
> get at home with the same cards, the same processor, with no polling and 
> throgh the same provider.
>
> Best regards,
> Bachilo Dmitry
>   
Dmitry,

Could you please try natd+kqueue patch from 
http://www.freebsd.az/patches.html  and report results (difference it 
made etc etc) ?
I did not have any chance to test it in heavy load environment.yet.

Thank you,
Tofig Suleymanov