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

[Max Gurtovoy]

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.

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


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