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

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

quoted

On Mon, Aug 20, 2018 at 09:39:45AM +0200, Ricardo Ribalda Delgado wrote:

quoted

Some measurements:

Please note that even when iostat shows 0.0 the LED on the device was
blinking as if there was some activity going on.

Thanks!

KERNEL:
Linux neopili 4.17.0-1-amd64 #1 SMP Debian 4.17.8-1 (2018-07-20)
x86_64 GNU/Linux

DISK:
[247530.712686] usb 2-2: new SuperSpeed USB device number 3 using xhci_hcd
[247530.738906] usb 2-2: New USB device found, idVendor=174c,
idProduct=5136, bcdDevice= 1.00
[247530.738913] usb 2-2: New USB device strings: Mfr=2, Product=3,
SerialNumber=1
[247530.738918] usb 2-2: Product: 91686
[247530.738921] usb 2-2: Manufacturer: Delock
[247530.738925] usb 2-2: SerialNumber: 300000003B45
[247530.750709] scsi host6: uas
[247530.751377] scsi 6:0:0:0: Direct-Access     ASMT     2105
   0    PQ: 0 ANSI: 6
[247530.752174] sd 6:0:0:0: Attached scsi generic sg2 type 0
[247530.752616] sd 6:0:0:0: [sdb] 31277232 512-byte logical blocks:
(16.0 GB/14.9 GiB)
[247530.752740] sd 6:0:0:0: [sdb] Write Protect is off
[247530.752742] sd 6:0:0:0: [sdb] Mode Sense: 43 00 00 00
[247530.752905] sd 6:0:0:0: [sdb] Write cache: enabled, read cache:
enabled, doesn't support DPO or FUA
[247530.755912]  sdb: sdb1 sdb2
[247530.756832] sd 6:0:0:0: [sdb] Attached SCSI disk


TL/DR:
CFQ: 21.7
NOOP: 21.7
DEADLINE: 21.7
MQ-DEADLINE: 175.2
NONE: 236.4
KYBER: 174.9

Thanks for your test!

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

-71 is -EPROTO, which is returned from xhci driver, usually it means
there is error from the USB device side.

[  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

It might be.

Is there such message in case of non-blk-mq?

thanks,
Ming