On Thu, Sep 06, 2018 at 04:24:12PM +0600, Artem Pisarenko wrote: > Hi all, > > I'm developing paravirtualized target linux system which runs multiple linux > containers (LXC) inside itself. (For those, who unfamiliar with LXC, simply > put, it's an isolated group of userspace processes with their own rootfs.) > Each > container should be provided access to its rootfs located at host and > execution > of container should be deterministic. Particularly, it means that container > I/O > operations must be synchronized within some predefined quantum of guest > _virtual_ time, i.e. its I/O activity shouldn't be delayed by host performance > or activities on host and other containers. In other words, guest should see > it's like either infinite throughput and zero latency, or some predefined > throughput/latency characteristics guaranteed per each rootfs. > > While other sources of non-determinism are seem to be eliminated (using TCG, > -icount, etc.), asynchronous I/O still introduces it.
... Just that you should realize that the issues are not limited to QEMU: to get real time behaviour out of a Linux host you need a real-time kernel and real-time capable hardware/firmware. I'm not an expert on this at all, but see e.g. these old presentations: https://lwn.net/Articles/656807/ -- MST
