On Wed, 2018-02-14 at 10:55 +0100, Oleksandr Natalenko wrote: > Hi. > > 14.02.2018 09:56, Paolo Valente wrote: > > This has evidently to do with tag pressure. I've looked for a way to > > easily reduce the number of tags online, so as to put your system in > > the bad spot deterministically. But at no avail. Does anyone know a > > way to do it? > > Isn't this a case for block device queue_depth? IIRC, the amount of tags > is derived from it. /sys/devices/pci0000:00/0000:00:1f.2/ata1/host0/target0:0:0/0:0:0:0/queue_depth /sys/devices/pci0000:00/0000:00:1f.2/ata6/host5/target5:0:0/5:0:0:0/queue_depth /sys/devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/queue_depth /sys/devices/pci0000:00/0000:00:1f.2/ata5/host4/target4:0:0/4:0:0:0/queue_depth FWIW, these guys are all 31.