Messages in this thread | | | Date | Wed, 4 Apr 2007 17:46:55 +0200 | From | Ingo Molnar <> | Subject | Re: [patch 04/17] Add pagetable accessors to pack and unpack pagetable entries |
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* Jeremy Fitzhardinge <jeremy@goop.org> wrote:
> Ingo Molnar wrote: > > the main metric we are interested in is the overhead for people who just > > want to run the non-patched native kernel that has CONFIG_PARAVIRT > > enabled (99%+ of the users at the moment), so the delta is: > > > > null: +12.0% > > null IO: +7.5% > > stat: within noise > > open/close: within noise > > TCP: ~5.0% > > signal install: 2.0% > > signal handle: 4.7% > > fork: 2.7% > > exec: 3.6% > > shell: 3.6% > > > > Hm, I don't think you can get this much precision out of these > numbers. I noticed larger variations from boot-to-boot running the > same test.
sure. i simply took the middle numbers. But there's definitely a 'few percents' trend in the numbers.
> > this is not 'barely measurable' but 'BLOODY LARGE' overhead. > > Yes. Fortunately there's a noticable difference between native and > unpatched paravirt, because it shows all the effort we put into > patching is worthwhile.
if only it were not such an ugly piece of code? ;)
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