Hi Ryo, Ryo Tsuruta wrote: > Hello all, > > I've implemented a block device which throttles block I/O bandwidth, > which I called dm-ioband, and been trying to throttle I/O bandwidth on > KVM environment. But unfortunately it doesn't work well, the number of > issued I/Os is not according to the bandwidth setting. > On the other hand, I got the good result when accessing directly to > the local disk on the local machine. > > I'm not so familiar with KVM. Could anyone give me any advice? If you are using virtio drivers in the guest (which I presume you are given the reference to /dev/vda), try using the following -drive syntax: -drive file=/dev/mapper/ioband1,if=virtio,boot=on,cache=off This will force the use of O_DIRECT. By default, QEMU does not open with O_DIRECT so you'll see page cache effects. Regards, Anthony Liguori _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
