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

[Max Gurtovoy <mgurtovoy@nvidia.com>]

On 12/16/2021 4:18 AM, Yi Zhang wrote:
> On Wed, Dec 15, 2021 at 8:10 PM Max Gurtovoy <mgurtovoy@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@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?

{
   "hosts": [],
   "ports": [
     {
       "addr": {
         "adrfam": "ipv4",
         "traddr": "<ip>",
         "treq": "not specified",
         "trsvcid": "4420",
         "trtype": "rdma"
       },
       "portid": 1,
       "referrals": [],
       "subsystems": [
         "testsubsystem_0"
       ]
     }
   ],
   "subsystems": [
     {
       "allowed_hosts": [],
       "attr": {
         "allow_any_host": "1",
         "cntlid_max": "65519",
         "cntlid_min": "1",
         "model": "Linux",
         "serial": "3d83c78b76623f1d",
         "version": "1.3"
       },
       "namespaces": [
         {
           "device": {
             "nguid": "5b722b05-e9b6-542d-ba80-62010b57775d",
             "path": "/dev/nullb0",
             "uuid": "26ffc8ce-73b4-321d-9685-7d7a9872c460"
           },
           "enable": 1,
           "nsid": 1
         }
       ],
       "nqn": "testsubsystem_0"
     }
   ]
}


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

I did this experiment. I have only a setup with 12 cores so I created 12 
nvmf queues.

The reset took 4 seconds. The test did 100 loops of "nvme reset".

I saw that you also complained on the disconnect flow so I assume the 
root cause is the same.

My disconnect took 2 seconds.

My FW version is 12.28.2006.

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