Re: [patch 0/3] kvm tool: Serial emulation overhaul

From: Ingo Molnar
Date: Mon Dec 12 2011 - 12:23:33 EST



* Sasha Levin <levinsasha928@xxxxxxxxx> wrote:

> > You can emulate a chip with a 64byte or so FIFO. You can do
> > I/O cycle prediction in the kernel part and you can use the
> > empty bit as a clue (which is what most serial<->ethernet
> > widgetry does).
>
> The performance problems here aren't the same performance
> problems you have on real hardware. The problem here is that
> it costs 40k cycles for the guest to access the emulated chip.

I question that 40k cycles figure - where does Marcelo's paper
mention it?

Thanks,

Ingo
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