It is a CFast connected via USB3 Digging a bit, seems to be related to the module option:
scsi_mod.use_blk_mq which is true on the new kernel and false on the old kernel. On Fri, Aug 17, 2018 at 12:12 PM Simon McVittie <s...@debian.org> wrote: > > On Fri, 17 Aug 2018 at 10:27:47 +0200, Ricardo Ribalda Delgado wrote: > > Current version of bmap on combination with the current debian kernel gives > > a > > terrible low performance: > ... > > $sudo bmaptool copy image.wic /dev/sdb > > What sort of hardware is /dev/sdb? I think recent kernels offer different > classes of scheduler for (rotating, magnetic) hard disks and for > solid-state storage, which might explain why you see none instead of noop. > > If you copy a raw image to the same device on each kernel (without using > bmaptool to skip unused blocks), how long does it take with the default > scheduler, and how long does it take with the noop or none scheduler > (whichever is available)? > > If there has been a general performance regression in the kernel for > this device type, there is unlikely to be anything that bmaptool can do > about it, but a refinement of the patch you suggested (checking which > schedulers are available, and selecting either noop or none, whichever > is available) would make sense. > > smcv -- Ricardo Ribalda
