On Mon, Aug 20, 2018 at 09:39:45AM +0200, Ricardo Ribalda Delgado wrote: > 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. 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. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2d5ba0e2de24ec87636244a01d4e78d095cc1b20 So could you test v4.18 and see if there is such issue? BTW, I have run the same test on usb-storage, and can't reproduce it. However you are using UAS, and I don't have it at hand, so can't reproduce it completely. Thanks, Ming
