On 2019/11/08 4:00, Andrea Vai wrote: > [Sorry for the duplicate message, it didn't reach the lists due to > html formatting] > Il giorno gio 7 nov 2019 alle ore 08:54 Damien Le Moal > <Damien.LeMoal@xxxxxxx> ha scritto: >> >> On 2019/11/07 16:04, Andrea Vai wrote: >>> Il giorno mer, 06/11/2019 alle 22.13 +0000, Damien Le Moal ha scritto: >>>> >>>> >>>> Please simply try your write tests after doing this: >>>> >>>> echo mq-deadline > /sys/block/<name of your USB >>>> disk>/queue/scheduler >>>> >>>> And confirm that mq-deadline is selected with: >>>> >>>> cat /sys/block/<name of your USB disk>/queue/scheduler >>>> [mq-deadline] kyber bfq none >>> >>> ok, which kernel should I test with this: the fresh git cloned, or the >>> one just patched with Alan's patch, or doesn't matter which one? >> >> Probably all of them to see if there are any differences. > > with both kernels, the output of > cat /sys/block/sdh/queue/schedule > > already contains [mq-deadline]: is it correct to assume that the echo > command and the subsequent testing is useless? What to do now? Probably, yes. Have you obtained a blktrace of the workload during these tests ? Any significant difference in the IO pattern (IO size and randomness) and IO timing (any device idle time where the device has no command to process) ? Asking because the problem may be above the block layer, with the file system for instance. > > Thanks, and bye > Andrea > -- Damien Le Moal Western Digital Research
