Hello Paolo On Fri, Aug 17, 2018 at 7:35 PM Paolo Valente <paolo.valente@xxxxxxxxxx> wrote: > > > > > Il giorno 17 ago 2018, alle ore 19:31, Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx> ha scritto: > > > > 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? > > > > Have you also checked what happens after switching to a different I/O > scheduler for the involved drive (among none, mq-deadline, bfq and > kyber)? I have only tried mq-deadline and none (because they are enabled by default on Debian). Both produce results in the same range: 5-8 times slower. I could easily enable kyber: cat /boot/config-4.17.0-1-amd64 | grep CONFIG_MQ_IOSCHED CONFIG_MQ_IOSCHED_DEADLINE=y CONFIG_MQ_IOSCHED_KYBER=m But I left the card reader on the office, so any test would have to wait until monday sorry :( > > Paolo > > > Thanks! > > > > -- > > Ricardo Ribalda > -- Ricardo Ribalda
