[bug report] NVMe/IB: reset_controller need more than 1min

[Yi Zhang]

On Wed, Dec 15, 2021 at 8:10 PM Max Gurtovoy <mgurtovoy at nvidia.com> wrote:
>
>
> On 12/15/2021 3:15 AM, Yi Zhang wrote:
> > On Tue, Dec 14, 2021 at 8:01 PM Max Gurtovoy <mgurtovoy at nvidia.com> wrote:
> >>
> >> On 12/14/2021 12:39 PM, Sagi Grimberg wrote:
> >>>>>> Hi Sagi
> >>>>>> It is still reproducible with the change, here is the log:
> >>>>>>
> >>>>>> # time nvme reset /dev/nvme0
> >>>>>>
> >>>>>> real    0m12.973s
> >>>>>> user    0m0.000s
> >>>>>> sys     0m0.006s
> >>>>>> # time nvme reset /dev/nvme0
> >>>>>>
> >>>>>> real    1m15.606s
> >>>>>> user    0m0.000s
> >>>>>> sys     0m0.007s
> >>>>> Does it speed up if you use less queues? (i.e. connect with -i 4) ?
> >>>> Yes, with -i 4, it has stablee 1.3s
> >>>> # time nvme reset /dev/nvme0
> >>> So it appears that destroying a qp takes a long time on
> >>> IB for some reason...
> >>>
> >>>> real 0m1.225s
> >>>> user 0m0.000s
> >>>> sys 0m0.007s
> >>>>
> >>>>>> # dmesg | grep nvme
> >>>>>> [  900.634877] nvme nvme0: resetting controller
> >>>>>> [  909.026958] nvme nvme0: creating 40 I/O queues.
> >>>>>> [  913.604297] nvme nvme0: mapped 40/0/0 default/read/poll queues.
> >>>>>> [  917.600993] nvme nvme0: resetting controller
> >>>>>> [  988.562230] nvme nvme0: I/O 2 QID 0 timeout
> >>>>>> [  988.567607] nvme nvme0: Property Set error: 881, offset 0x14
> >>>>>> [  988.608181] nvme nvme0: creating 40 I/O queues.
> >>>>>> [  993.203495] nvme nvme0: mapped 40/0/0 default/read/poll queues.
> >>>>>>
> >>>>>> BTW, this issue cannot be reproduced on my NVME/ROCE environment.
> >>>>> Then I think that we need the rdma folks to help here...
> >>> Max?
> >> It took me 12s to reset a controller with 63 IO queues with 5.16-rc3+.
> >>
> >> Can you try repro with latest versions please ?
> >>
> >> Or give the exact scenario ?
> > Yeah, both target and client are using Mellanox Technologies MT27700
> > Family [ConnectX-4], could you try stress "nvme reset /dev/nvme0", the
> > first time reset will take 12s, and it always can be reproduced at the
> > second reset operation.
>
> I created a target with 1 namespace backed by null_blk and connected to
> it from the same server in loopback rdma connection using the ConnectX-4
> adapter.

Could you share your loop.json file so I can try it on my environment?

And can you try it with two servers that both have CX-4? This should
be easier to reproduce it.

>
> I run a loop with the "nvme reset" command and it took me 4-5 secs to
> reset each time..
>
>
> >
> >>
> >
>


-- 
Best Regards,
  Yi Zhang