Re: CONFIG_TULIP_NAPI_HW_MITIGATION latency question.

[Justin Piszcz <jpiszcz@lucidpixels.com>]

Thanks for the info.

On Thu, 25 Nov 2004, Robert Olsson wrote:

>
>
>
> Justin Piszcz writes:
> > "at the cost of a small latency"
> >
> > How much additional latency is added with this option enabled?
> >
> > 5ms? 10ms?
> >
> > -> Use Interrupt Mitigation
> >    x CONFIG_TULIP_NAPI_HW_MITIGATION:
> >    x Use HW to reduce RX interrupts. Not strict necessary since NAPI
> > reduces RX interrupts but itself. Although this reduces RX interrupts even at
> > low levels traffic at the cost of a small latency.
> > x
> >    x If in doubt, say Y.
>
> Hello!
>
> It's in usec and the tulip only enables this latency when it's needed it
> really tries to keep latency down.
>
> It has three steeps of input control.
>
> Low rate:     No driver latency. No interrupt delay at all.
> Medium rate:  Samll driver latency.
> High rate:    Polling via ->poll
>
> 						--ro
>