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Date: Thu, 4 Apr 2024 17:25:36 -0300
From: Jason Gunthorpe <jgg@nvidia.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Edward Cree <ecree.xilinx@gmail.com>, David Ahern <dsahern@kernel.org>,
	Jakub Kicinski <kuba@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Christoph Hellwig <hch@infradead.org>,
	Saeed Mahameed <saeed@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Leon Romanovsky <leonro@nvidia.com>, Jiri Pirko <jiri@nvidia.com>,
	Leonid Bloch <lbloch@nvidia.com>, Itay Avraham <itayavr@nvidia.com>,
	Saeed Mahameed <saeedm@nvidia.com>,
	Aron Silverton <aron.silverton@oracle.com>,
	linux-kernel@vger.kernel.org,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Andy Gospodarek <andrew.gospodarek@broadcom.com>
Subject: Re: [PATCH V4 0/5] mlx5 ConnectX control misc driver
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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