Donald Becker wrote:
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'm open to suggestions. However, I am running 4 or 8 ports simultaneously,
on a single processor machine, so w/out large receive buffers, I drop packets
horribly. If there is some magic number you think will be better than
others, I'll be happy to try it and report results...
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)?
- 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.
Thanks,
Ben
--
Ben Greear <greearb@xxxxxxxxxxxxxxx> <Ben_Greear AT excite.com>
President of Candela Technologies Inc http://www.candelatech.com
ScryMUD: http://scry.wanfear.com http://scry.wanfear.com/~greear
|