On 12/15/2021 3:15 AM, Yi Zhang wrote:

On Tue, Dec 14, 2021 at 8:01 PM Max Gurtovoy [off-list ref] wrote:

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On 12/14/2021 12:39 PM, Sagi Grimberg wrote:

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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...

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real 0m1.225s
user 0m0.000s
sys 0m0.007s

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# 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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