Re: [patch 3/3] x86: kvm guest side support for KVM_HC_RT_PRIO hypercall\

[Marcelo Tosatti]

On Thu, Sep 28, 2017 at 09:22:02AM +0200, Paolo Bonzini wrote:
> On 28/09/2017 02:44, Marcelo Tosatti wrote:
> >> Again: if you have many interruptions, it's not a flaw in KVM or QEMU's
> >> design, it's just that someone is doing something stupid.  It could be
> >> the guest (e.g. unnecessary devices or daemons as in the example above),
> >> QEMU (e.g. the RTC emulation used to trigger QEMU timers twice a second
> >> just to increment the clock), or the management (e.g. polling "is the VM
> >> running" 50 times per second).  But it can and must be fixed.
> >
> > No, i mean you can run anything in VCPU-0 (it is valid to do that).
> > And that "anything" can generate 1 interrupt per second, 1000 or 10.000
> > interrupts per second. Which are all valid things to be done.
> > 
> > "I can't run a kernel compilation on VCPU-0 because that will impact
> > latency on the realtime VCPU-1" is not acceptable.
> 
> That shouldn't happen.  Sources of frequent interruptions have all been
> fixed or moved outside the main thread.
> 
> If there are more left, report the bug and we'll see how to fix it in
> userspace.
> 
> Paolo

What should not happen? The generation of 10.000 interrupts per second
(say disk IO completion) on a given workload ?