On Wed, 6 Nov 2002, Ben Greear wrote:
> > I see you increased the RX-ring to 1024 pkts.
> > Did you really see any improvement with this?
>
> It helped drop fewer packets when running 4 ports at 92Mbps+
> However, the difference between that and 512 is not large.
Using 512 Rx buffers at 100Mbps seem like a pretty silly default.
> I would really like to make that size adjustable at module load
> time and/or runtime, but I'm not sure how easy that would be.
It's trivial for many (but not all) drivers.
I've been considering doing that with my driver release.
There is no longer a CPU cycle cost issue with ring-wrapping on an
arbitrary ring size.
> Imagine being able to crank up your receive buffers when running at
> very high speeds (and/or when you start dropping packets). At lower speeds,
> shrink things down and free up resources....
Being that dynamic involves writing code and extensive testing with all
of the different chips.
The trivial case is a module option that sets a variable replacing
RX_RING_SIZE / TX_RING_SIZE..
The passed-in value shouldn't be used directly:
- many drivers have upper and lower bounds
- the size can only be changed when the rings are initialized,
which occurs when the interface starts.
- users thinking "if 32 is good, 32000 is better"
> > Also I would be interested if you have any numbers for recycling patch?
interest++
--
Donald Becker becker@xxxxxxxxx
Scyld Computing Corporation http://www.scyld.com
410 Severn Ave. Suite 210 Scyld Beowulf cluster system
Annapolis MD 21403 410-990-9993
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