On Wed, 6 Nov 2002, Ben Greear wrote:

quoted

 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"

quoted

 Also I would be interested if you have any numbers for recycling patch? 

interest++

-- 
Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Scyld Beowulf cluster system
Annapolis MD 21403			410-990-9993