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

[Avi Kivity]

On 12/12/2011 08:31 PM, Pekka Enberg wrote:
> On Mon, 2011-12-12 at 20:19 +0200, Avi Kivity wrote:
> > On 12/12/2011 01:19 PM, Pekka Enberg wrote:
> > > On Sun, Dec 11, 2011 at 5:53 PM, Ingo Molnar <mingo@xxxxxxx> wrote:
> > > > Okay, but look at it from another angle: the top output i
> > > > generate is about 300k characters. 5000 msecs to execute it
> > > > means 16 usecs overhead per character - or about 50k cycles - on
> > > > a top of the class x86 CPU.
> > >
> > > I'm seeing 1.5 usecs per character for this little benchmark:
> > 
> > No interrupts, right?  Things look differently with one interrupt per
> > character and none. 
>
> No interrupts. I was simply trying to measure PIO overhead to see how
> bad the 15 usec per character Ingo measured really is.

Yeah.

Anyway, uart serial is never going to be fast.  That's what
virtio-serial is for.

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

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