device polling and weird timer interrupt count from vmstat

[Artem Kuchin]

Nikos Vassiliadis wrote:
> On Tuesday 25 September 2007 12:13, Artem Kuchin wrote:
>> I have dual CPU with HT. If i turn on HT (and it does help in my
>> case) it shoud 2000 int x4 = 8000 ints per second. SO, i have saved
>> 200 int/second from NIC and got myself 8000 ints/second from timer.
> 
> This kind of load(200intrs/s) earns nothing from polling.
> 
>> Did i
>> really win anything? I wish there were some good explanation on this.
> 
> It would make a difference for let's say 8000 - 10000 interrupts/sec.
> You should read polling(4). It explains a lot:)

Yes, i have read the man for polling. However, it does not contain 
info on when it worth enabling. From this point of view it seems like
if i have 8CPU server an a NIC with 8000 ints/sec when i enable polling 
with HZ=1000 i get

about 30 ints/sec from NIC
about 16000 ints from NIC

So, we were at 8000 ints a second and now we are at 16000 ints/second.
Is it worth in this case? It seems  like enabling polling on really multi
cpu computers never worth it. I think there is a mistake in my logic
here. It just canot be like this.

any thoughts?

--
Regards,
Artem