David S. Miller writes:
> From: "Michael Chan" <mchan@xxxxxxxxxxxx>
> Subject: Re: [TG3]: Add hw coalescing infrastructure.
> Date: Wed, 11 May 2005 14:17:36 -0700
> > Yes, and MTU size dependent too. But we may not want to coalesce the
> > same way when running at 10/100 Mbps. For example, if one packet has
> > arrived, we don't want to wait 120 usec or 1200 usec to see if another
> > packet will arrive before we interrupt at 100 and 10 Mbps respectively.
>
> That's a good point. I think it would be wise for us to try
> and come up with a dynamic mitigation algorithm that is as MTU
> and link speed agnostic as possible.
Size of RX-ring is also to be taken to account. You probably have to design
for samllest packets otherwise you risk RX-ring overrun and packet drop.
> One thing to note is that what we're really trying to do is
> maximize the amount of work done per interrupt, without
> unduly adding latency to packet reception.
>
> Work done per-interrupt, and maximum latency, are better goals
> because formulas based upon those values will automatically take
> differences in CPU and BUS I/O speed into account.
Yes.
Cheers.
--ro
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