Re: [patch 1/3] QEMU/KVM: separate thread for IO handling

[Avi Kivity <avi@qumranet.com>]

Marcelo Tosatti wrote:
> Move IO processing from vcpu0 to a dedicated thread.
>
> This removes load on vcpu0 by allowing better cache locality and also
> improves latency.
>
>   

Does live migration (and stop/cont) still work with this?

> We can now block signal handling for IO events, so sigtimedwait won't
> race with handlers:
>
> - Currently the SIGALRM handler fails to set CPU_INTERRUPT_EXIT because
> the "next_cpu" variable is not initialized in the KVM path, meaning that
> processing of timer expiration might be delayed until the next vcpu0 exit.
>   

I still don't understand this.  Timer expiration ought to be processed 
in the iothread, when SIGALRM is dequeued, and be completely unrelated 
to whatever vcpu 0 is doing.


> - Processing of IO events will not be unnecessarily interrupted.
>   

What do you mean by this?

-- 
error compiling committee.c: too many arguments to function


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