Re: [dpdk-dev] [PATCH] [RFC] vhost: inroduce operation to get vDPA queue stats

[Matan Azrad <matan@mellanox.com>]

From: Maxime Coquelin
> Sent: Friday, April 10, 2020 5:04 PM
> To: Matan Azrad <matan@mellanox.com>; dev@dpdk.org
> Cc: Slava Ovsiienko <viacheslavo@mellanox.com>; Shahaf Shuler
> <shahafs@mellanox.com>; Xiao Wang <xiao.w.wang@intel.com>; Tiwei Bie
> <tiwei.bie@intel.com>
> Subject: Re: [PATCH] [RFC] vhost: inroduce operation to get vDPA queue
> stats
> 
> 
> 
> On 4/10/20 3:54 PM, Matan Azrad wrote:
> > Hi Maxime
> >
> > From: Maxime Coquelin
> >> Hi Matan,
> >>
> >> On 3/16/20 4:12 PM, Matan Azrad wrote:
> >>> The vDPA device offloads all the datapath of the vhost device to the
> >>> HW device.
> >>>
> >>> In order to expose to the user traffic information this patch
> >>> introduce new API to get traffic statistics per virtio queue.
> >>>
> >>> The statistics are taken directly from the vDPA driver managing the
> >>> HW device.
> >>
> >> Shouldn't the stats be collected from the PF like for "legacy" SR-IOV
> >> via the sysfs?
> >> Something like:
> >> /sys/class/net/<PF name>/device/sriov/<VF ID>/stats/
> >
> > Yes, probably, statistics can be taken from sysfs.
> >
> > But we are introducing a DPDK API to get the virtio statistics.
> > So, driver which can take statistics from there can take them from sysfs in
> the driver operation.
> >
> > In addition, the API includes per virtio queue statistics and in virtio data-
> path terms, it is very helpful for debuggability.
> 
> Ok, the per queue stats is a valid point for queue debug.
> 
> Even if we add this API, I still think we should ensure the stats will be
> available through the sysfs, so that it makes Kubernetes integration seemless
> wrt to legacy SR-IOV[0].

For Mellanox legacy SRIOV the sysfs stats you mentioned are available.

> Also, it would provide a single way to get statistics for both DPDK and Kernel
> vDPA.

Sure.

> Thanks,
> Maxime
> 
> >
> >
> >> Regards,
> >> Maxime
> >