Re: 2 Questions about Linux

Itai Nahshon (nahshon@actcom.co.il)
Tue, 03 Feb 1998 15:29:13 +0200

Alan Cox wrote:
>
> > But what is the overhead of doing this? I'd like not to impact the flow of data
> > as much as possible (TCP driver). How much CPU can I expect that call to
> > chew up?
>
> On a PPro or Pentium its about 70 clocks or so - not good but not too bad.

The time code in the pentium (I think PPro as well) takes a different
path if APM is defined. I do not know what is the overhead in that case
but
it is probably much higher.

> If you are really serious put a hardware time stamper on the interrupt
> line, and set the skb->stamp field in the driver. Been there, done that 8)
>
> Alan

-- 
Itai Nahshon   nahshon@actcom.co.il
        Also   nahshon@vnet.ibm.com