Hi Ben
On Wed, Aug 22, 2018 at 9:22 PM Ben Hutchings [off-list ref] wrote:

On Mon, 2018-08-20 at 11:04 +0200, Ricardo Ribalda Delgado wrote:

quoted

Hello Ming
On Mon, Aug 20, 2018 at 10:30 AM Ming Lei [off-list ref] wrote:

[...]

quoted

quoted

One problem found from your iostat log is that looks there is ~30sec
idle period between IO activities when blk-mq is enabled.

During all the test the LED on the device was blinking.

But a closer look to dmesg reveals a lot of this messages:

[  196.929811] sd 6:0:0:0: [sdb] tag#3 data cmplt err -71 uas-tag 1
inflight: CMD
[  196.929822] sd 6:0:0:0: [sdb] tag#3 CDB: Write(10) 2a 00 00 04 00
68 00 04 00 00
[  227.764379] sd 6:0:0:0: [sdb] tag#4 uas_eh_abort_handler 0 uas-tag
2 inflight: CMD OUT
[  227.764389] sd 6:0:0:0: [sdb] tag#4 CDB: Write(10) 2a 00 00 04 04
68 00 04 00 00
[  227.766555] sd 6:0:0:0: [sdb] tag#3 uas_eh_abort_handler 0 uas-tag
1 inflight: CMD
[  227.766562] sd 6:0:0:0: [sdb] tag#3 CDB: Write(10) 2a 00 00 04 00
68 00 04 00 00
[  227.784312] scsi host6: uas_eh_device_reset_handler start
[  227.913672] usb 2-2: reset SuperSpeed USB device number 3 using xhci_hcd
[  227.944842] scsi host6: uas_eh_device_reset_handler success
[  231.416133] sd 6:0:0:0: [sdb] tag#1 data cmplt err -71 uas-tag 10
inflight: CMD
[  231.416147] sd 6:0:0:0: [sdb] tag#1 CDB: Write(10) 2a 00 00 06 d5
e8 00 04 00 00

And they take around 30 secons (227-196)


Maybe this is a hw issue? I will bring the reader home tonight and see
if I can replicate the bug with my notebook

quoted

Maybe it is related with timeout, given we had big change in v4.17 timeout code,
and we also fixed one scsi_mq timeout related issue recently, and the patch[1] has
been merged to v4.18 release already.

I tried with v4.18-rc4 (latest one packaged in debian experimental)
and after 3 runs, 2 were fine (27 sec), but the last one was over a
minute.

Is it possible that this is fixed by "block: really disable runtime-pm
for blk-mq"?

That fix went into Debian's version 4.17.14-1, but is not yet in any
4.18-based package.

Just tried out
ricardo@neopili:~$ uname -a
Linux neopili 4.17.0-3-amd64 #1 SMP Debian 4.17.17-1 (2018-08-18)
x86_64 GNU/Linux

and after around 10 executions all the runtimes are similar to the
ones with non-blk-mq and I havent seen the "uas error" on dmesg

Thanks for your help.

I will keep an eye on the issue in case it triggers again

Ben.

--
Ben Hutchings
You can't have everything.  Where would you put it?

-- 
Ricardo Ribalda