On Wed, 6 Nov 2002, Ben Greear wrote:

quoted

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.

So, adjusting the ring size would require stopping and starting the
NIC?  Is that a full bounce (including auto-negotiation)?

Most chips do not require bouncing the link when the interface is cycled
down/up.  That's not to say that some drivers don't reset the link --
it's easier for the driver writer to write the code that way, and doing
the link reset can mask other problems.

quoted

 - users thinking "if 32 is good, 32000 is better"

The sad truth is, most NICs/drivers do not perform at high
speeds w/out hacking them in various ways.  Where to lay the
blame (VM, shitty hardware, etc) is debatable, but it doesn't
change the results.  I do know that 1024 is better than 32 for
high speeds on muliple ports, on my NICs.

I can see that changing the parameters is a quick, ad hoc solution.
This list should focus on identifying the problems, rather than just
patching in work-arounds.

-- 
Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
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