Re: [PATCH net-next 13/13] devlink, ice: add MSIX vectors as devlink resource

[Michal Swiatkowski <michal.swiatkowski@linux.intel.com>]

On Mon, Nov 14, 2022 at 05:03:43PM +0100, Piotr Raczynski wrote:
> On Mon, Nov 14, 2022 at 04:28:38PM +0100, Jiri Pirko wrote:
> > Mon, Nov 14, 2022 at 01:57:55PM CET, michal.swiatkowski@linux.intel.com wrote:
> > >From: Michal Kubiak <michal.kubiak@intel.com>
> > >
> > >Implement devlink resource to control how many MSI-X vectors are
> > >used for eth, VF and RDMA. Show misc MSI-X as read only.
> > >
> > >This is first approach to control the mix of resources managed
> > >by ice driver. This commit registers number of available MSI-X
> > >as devlink resource and also add specific resources for eth, vf and RDMA.
> > >
> > >Also, make those resources generic.
> > >
> > >$ devlink resource show pci/0000:31:00.0
> > >  name msix size 1024 occ 172 unit entry dpipe_tables none
> > 
> > 
> > So, 1024 is the total vector count available in your hw?
> > 
> 
> For this particular device and physical function, yes.
> 
> 
> > 
> > >    resources:
> > >      name msix_misc size 4 unit entry dpipe_tables none
> > 
> > What's misc? Why you don't show occupancy for it? Yet, it seems to be
> > accounted in the total (172)
> > 
> > Also, drop the "msix_" prefix from all, you already have parent called
> > "msix".
> 
> misc interrupts are for miscellaneous purposes like communication with
> Firmware or other control plane interrupts (if any).
> 

I will drop msix_ prefix. I didn't show the occupancy because it is the
same all the time and user can't change it. But You are righ it is
accounted, so I will add occupancy also here in next version.

> > 
> > 
> > >      name msix_eth size 92 occ 92 unit entry size_min 1 size_max
> > 
> > Why "size_min is not 0 here?
> 
> Thanks, actually 0 would mean disable the eth, default, netdev at all.
> It could be done, however not implemented in this patchset. But for
> cases when the default port is not needed at all, it seems like a good
> idea.
>

I will try to do it in next version, thanks.

> > 
> > 
> > >	128 size_gran 1 dpipe_tables none
> > >      name msix_vf size 128 occ 0 unit entry size_min 0 size_max
> > >	1020 size_gran 1 dpipe_tables none
> > >      name msix_rdma size 76 occ 76 unit entry size_min 0 size_max
> > 
> > Okay, this means that for eth and rdma, the vectors are fully used, no
> > VF is instanciated?
> 
> Yes, in this driver implementation, both eth and rdma will most probably
> be always fully utilized, but the moment you change the size and execute
> `devlink reload` then they will reconfigure with new values.
> 
> The VF allocation here is the maximum number of interrupt vectors that
> can be assigned to actually created VFs. If so, then occ shows how many
> are actually utilized by the VFs.
> 
> > 
> > 
> > 
> > >	132 size_gran 1 dpipe_tables none
> > >
> > >example commands:
> > >$ devlink resource set pci/0000:31:00.0 path msix/msix_eth size 16
> > >$ devlink resource set pci/0000:31:00.0 path msix/msix_vf size 512
> > >$ devlink dev reload pci/0000:31:00.0