RE: [PATCH net-next 00/13] resource management using devlink reload

["Keller, Jacob E" <jacob.e.keller@intel.com>]

> -----Original Message-----
> From: Samudrala, Sridhar <sridhar.samudrala@intel.com>
> Sent: Monday, November 14, 2022 7:31 AM
> To: Leon Romanovsky <leon@kernel.org>; Michal Swiatkowski
> <michal.swiatkowski@linux.intel.com>
> Cc: netdev@vger.kernel.org; davem@davemloft.net; kuba@kernel.org;
> pabeni@redhat.com; edumazet@google.com; intel-wired-lan@lists.osuosl.org;
> jiri@nvidia.com; Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Lobakin,
> Alexandr <alexandr.lobakin@intel.com>; Drewek, Wojciech
> <wojciech.drewek@intel.com>; Czapnik, Lukasz <lukasz.czapnik@intel.com>;
> Saleem, Shiraz <shiraz.saleem@intel.com>; Brandeburg, Jesse
> <jesse.brandeburg@intel.com>; Ismail, Mustafa <mustafa.ismail@intel.com>;
> Kitszel, Przemyslaw <przemyslaw.kitszel@intel.com>; Raczynski, Piotr
> <piotr.raczynski@intel.com>; Keller, Jacob E <jacob.e.keller@intel.com>; Ertman,
> David M <david.m.ertman@intel.com>; Kaliszczuk, Leszek
> <leszek.kaliszczuk@intel.com>
> Subject: Re: [PATCH net-next 00/13] resource management using devlink reload
> 
> On 11/14/2022 7:23 AM, Leon Romanovsky wrote:
> > On Mon, Nov 14, 2022 at 01:57:42PM +0100, Michal Swiatkowski wrote:
> >> Currently the default value for number of PF vectors is number of CPUs.
> >> Because of that there are cases when all vectors are used for PF
> >> and user can't create more VFs. It is hard to set default number of
> >> CPUs right for all different use cases. Instead allow user to choose
> >> how many vectors should be used for various features. After implementing
> >> subdevices this mechanism will be also used to set number of vectors
> >> for subfunctions.
> >>
> >> The idea is to set vectors for eth or VFs using devlink resource API.
> >> New value of vectors will be used after devlink reinit. Example
> >> commands:
> >> $ sudo devlink resource set pci/0000:31:00.0 path msix/msix_eth size 16
> >> $ sudo devlink dev reload pci/0000:31:00.0
> >> After reload driver will work with 16 vectors used for eth instead of
> >> num_cpus.
> > By saying "vectors", are you referring to MSI-X vectors?
> > If yes, you have specific interface for that.
> > https://lore.kernel.org/linux-pci/20210314124256.70253-1-leon@kernel.org/
> 
> This patch series is exposing a resources API to split the device level MSI-X vectors
> across the different functions supported by the device (PF, RDMA, SR-IOV VFs
> and
> in future subfunctions). Today this is all hidden in a policy implemented within
> the PF driver.
> 
> The patch you are referring to seems to be providing an interface to change the
> msix count for a particular VF. This patch is providing a interface to set the total
> msix count for all the possible VFs from the available device level pool of
> msix-vectors.
> 

It looks like we should implement both: resources to configure the "pool" of available vectors for each VF, and the sysfs VF Interface to allow configuring individual VFs.

Thanks,
Jake