Re: [PATCH net-next] vmxnet3: increase default rx ring sizes

[David Miller <davem@davemloft.net>]

From: Shrikrishna Khare <skhare@vmware.com>
Date: Tue, 28 Nov 2017 13:12:04 -0800

> We often notice rx packet drops due to small default rx ring sizes and
> solve the problem by increasing the ring sizes. This patch increases the
> default rx ring sizes thereby reducing the probability of rx packet
> drops out of the box.
> 
> Signed-off-by: Shrikrishna Khare <skhare@vmware.com>
> Acked-by: Jin Heo <heoj@vmware.com>
> Acked-by: Guolin Yang <gyang@vmware.com>
> Acked-by: Boon Ang <bang@vmware.com>

That's not enough for me.

If you're going to quadruple your default RX ring size I want to
hear more about the research you did into the packet drops and
whether other things can be done to solve the problem.

Is something holding onto the packets unnecessarily long?

Is something blocking interrupts (hardware or software)?

Is an offload miscoded or misbehaving?

Is there a problem with the RX ring replenish algorithm of the
driver or it's heuristics?

Tell me more about that than just "bumping the RX ring
size fixes the problem".

Thank you.