[pve-devel] iothread support

[Eric Blevins]

Any plans to support iothreads in the future?

It makes a significant difference in IOPS on my windows 2012R2 guest.

cache=none, virtio, discard enabled:
Random Read 4KB (QD=32) :   190.467 MB/s [ 46500.7 IOPS]
Random Write 4KB (QD=32) :   170.091 MB/s [ 41526.2 IOPS]

iothread, cache=none, discard enabled:
Random Read 4KB (QD=32) :   349.899 MB/s [ 85424.6 IOPS] +38923.9
Random Write 4KB (QD=32) :   221.866 MB/s [ 54166.6 IOPS] +12640.4

To enable iothreads I added this to my vm.conf:
args: -object iothread,id=iothread0 -drive
file=/dev/drbd2-vm7-vm8/vm-109-disk-5,if=none,id=drive-virtio4,cache=none,discard=on,aio=native,detect-zeroes=unmap
-device virtio-blk-pci,drive=drive-virtio4,id=virtio4,bus=pci.0,addr=0xe,iothread=iothread0

Eric