Hi Anthony, I started a guest with cache=none and aio=threads
When i did some io tests in Guest say dd like dd if=/dev/zero oflag=direct of=/mnt/sdb1/date.img bs=4k count=262114 qemu will start one or several threads to perform IO requests. It seems qemu makes use of its own posixaio. I'm wondering how qemu decides how many threads should be created to perform io operation? Thanks, Gui
