From: Anthony Liguori <anthony-rdkfGonbjUSkNkDKm+mE6A@public.gmane.org>
To: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
Dan <berkovid-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: performance specs on VT-x vmenter/exit
Date: Thu, 06 Dec 2007 13:56:16 -0600 [thread overview]
Message-ID: <475853E0.7080005@codemonkey.ws> (raw)
In-Reply-To: <47584832.9010708-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
Avi Kivity wrote:
> Anthony Liguori wrote:
>>>
>>>
>>> Have a look at user/test/x86/vmexit.c, which does exactly that.
>>>
>>>
>>
>> That only gives you the combined count of a vmenter and vmexit.
>
> Right; furthermore it measures kvm overhead and not just instruction
> latency.
True. Also, I don't know what Dan is looking to measure, but the cost
of vmexits will varying depending on the reason for exit. vmexit.c uses
cpuid() which I suspect is slower than vmexit or pio but faster than
pf. It would be interesting to measure the individual exit reasons.
Regards,
Anthony Liguori
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next prev parent reply other threads:[~2007-12-06 19:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-06 18:09 performance specs on VT-x vmenter/exit Dan
[not found] ` <fe801d6f0712061009r7b6c64b5qa1ad17722036301b-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2007-12-06 18:36 ` Avi Kivity
[not found] ` <47584142.10600-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-12-06 18:49 ` Anthony Liguori
[not found] ` <4758442B.8060401-rdkfGonbjUSkNkDKm+mE6A@public.gmane.org>
2007-12-06 19:06 ` Avi Kivity
[not found] ` <47584832.9010708-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-12-06 19:56 ` Anthony Liguori [this message]
[not found] ` <475853E0.7080005-rdkfGonbjUSkNkDKm+mE6A@public.gmane.org>
2007-12-06 21:17 ` Dan
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