On Thu, Oct 08, 2015 at 07:59:56PM +0800, charlie.song wrote: > We recently try to use Linux AIO from guest OS and find that the IOthread mechanism of Qemu-KVM will reorder I/O requests from guest OS > even when the AIO write requests are issued from a single thread in order. This does not happen on the host OS however. I think you are describing a situation where a guest submits multiple overlapping I/O requests at the same time. virtio-blk does not guarantee a specific request ordering, so the application needs to wait for request completion if ordering matters. io_submit(2) also does not make guarantees about ordering. Stefan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html