Re: [dpdk-dev] [RFC 00/14] mlx5: support SubFunction

["Xia, Chenbo" <chenbo.xia@intel.com>]

Hi Thomas,

> -----Original Message-----
> From: Thomas Monjalon <thomas@monjalon.net>
> Sent: Thursday, June 10, 2021 9:23 PM
> To: Yigit, Ferruh <ferruh.yigit@intel.com>
> Cc: Xueming Li <xuemingl@nvidia.com>; Viacheslav Ovsiienko
> <viacheslavo@nvidia.com>; dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>
> Subject: Re: [dpdk-dev] [RFC 00/14] mlx5: support SubFunction
> 
> 10/06/2021 12:33, Ferruh Yigit:
> > On 5/27/2021 2:37 PM, Xueming Li wrote:
> > > SubFunction [1] is a portion of the PCI device, a SF netdev has its
> own
> > > dedicated queues(txq, rxq). A SF shares PCI level resources with other
> > > SFs and/or with its parent PCI function. Auxiliary bus is the
> > > fundamental of SF.
> > >
> > > This patch set introduces SubFunction support for mlx5 PMD driver
> > > including class net, regex, vdpa and compress.
> > >
> >
> > There is already an mdev patch, originated from long ago. Aren't
> subfunctions
> > presented as mdev device? If so can't we use mdev for it?
> 
> No unfortunately that's different.
> mlx5 SF is based on top of auxiliary bus in the kernel/sysfs.
> 

Just out of curiosity:

Does SF use mdev before aux bus is introduced in kernel. I see some history
of it but am not sure: [1] seems SF was base on mdev. [2] seems BlueField
software v2.5 is using mdev for SF. I saw it yesterday and try to figure
out the history. Since you are here, guess you know something 😊

[1] https://patchwork.ozlabs.org/project/netdev/cover/20191107160448.20962-1-parav@mellanox.com/
[2] https://docs.mellanox.com/display/BlueFieldSWv25011176/Mediated+Devices