Messages in this thread | | | Subject | Re: [patch 0/3] kvm tool: Serial emulation overhaul | From | Pekka Enberg <> | Date | Mon, 12 Dec 2011 20:31:38 +0200 |
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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@elte.hu> 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.
Pekka
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