On Sat, Aug 18, 2018 at 1:32 AM Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx> wrote: > > Hello > > Coming from: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=906328 > > bmaptools is kind of a "smart dd" tool, that lets you write images > very fast and securely. Since the last Debian Kernel update it has > become 5-8 times slower. > > After some debugging, we have figured out that the reason for that > slowness is the Multi-Queue Block IO Queueing Mechanism. > > Debian maintainer has pointed out that in the near future the single > queue will be deprecated. > > My question is if we can get a similar perfomance for bmaptools with > blk-mq and how? It suppose to be not worse than non-blk-mq, and maybe there is bug somewhere. Could you use 'iostat -dx $DISK_PATH 1' to collect io stat when running bmaptools in both blk-mq and non-blk-mq? BTW, don't change the default io scheduler as none, which shouldn't work well for slow disk, such as non-SSD. Thanks, Ming Lei
