On Thu, 7 Apr 2016 11:48:27 +0200 Pradeep Kiruvale <pradeepkiruv...@gmail.com> wrote:
> Hi All, > > I am using virtio-9p for sharing the file between host and guest. To test > the shared file I do read/write options in the guest.To have controlled io, > I am using cgroup blkio. > > While using cgroup I am facing two issues,Please find the issues below. > > 1. When I do IO throttling using the cgroup the read throttling works fine > but the write throttling does not wok. It still bypasses these throttling > control and does the default, am I missing something here? > Hi, Can you provide details on your blkio setup ? > I use the following commands to create VM, share the files and to > read/write from guest. > > *Create vm* > qemu-system-x86_64 -balloon none .......-name vm0 -cpu host -m 128 -smp 1 > -enable-kvm -parallel .... -fsdev > local,id=sdb1,path=/mnt/sdb1,security_model=none,writeout=immediate -device > virtio-9p-pci,fsdev=sdb1,mount_tag=sdb1 > > *Mount file* > mount -t 9p -o trans=virtio,version=9p2000.L sdb1 /sdb1_ext4 2>>dd.log && > sync > > touch /sdb1_ext4/dddrive > > *Write test* > dd if=/dev/zero of=/sdb1_ext4/dddrive bs=4k count=800000 oflag=direct >> > dd.log 2>&1 && sync > > *Read test* > dd if=/sdb1_ext4/dddrive of=/dev/null >> dd.log 2>&1 && sync > > 2. The other issue is when I run "dd" command inside guest it creates > multiple threads to write/read. I can see those on host using iotop is this > expected behavior? > Yes. QEMU uses a thread pool to handle 9p requests. > Regards, > Pradeep Cheers. -- Greg