Subject: Re: [PATCH V4 0/5] mlx5 ConnectX control misc driver

From: Jason Gunthorpe <[email-masked]>
Date: Thu, 4 Apr 2024 17:25:36 -0300

On Thu, Apr 04, 2024 at 08:44:56PM +0200, Andrew Lunn wrote:
> > > There are something like 600-800 configurables in mlx5
> 
> I keep seeing that 600-800, and thinking that 2 to the power 600 is a
> very big number, assuming they are simple on/off configurations.
> 
> Does any user actually have the 'optimal' configuration? How can they
> even know?

First, the big number is the union of all configurables on all devices
released over the past 20 years that work with the mlx5
driver. Looking at a single device will see a much smaller number of
configurable.

Second, much of it is not performance tuning. The site has a
functional workload they need to run and configurations need to be
adjusted to match.

For instance there is a bunch that configure the UEFI option
rom. Various devices can PXE boot, iSCSI boot and so on.

There is other stuff to turn on/off functional features which can be
quite often because stuff just needs to be known at FLR time.

I'm sure there are things in a more classical tunable space but it
going to be a more workably small number than 600..

Jason