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RE: [Xen-devel] Measure performance of hypercalls

To: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>, Tommy Huang <nbp0204@xxxxxxxxx>
Subject: RE: [Xen-devel] Measure performance of hypercalls
From: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Date: Wed, 15 Oct 2008 07:00:23 -0700 (PDT)
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> If you want to find the performance of hypercalls, you'll have to add
> some instrumentation.  You can extend xentrace to find out the number
> of *cycles* executed in a hypercall by taking a trace (with a
> timestamp) at hypercall entry and exit.  We do this already for
> vmenter/vmexit.

Hmmm... lots of interesting things can happen between a hypercall
entry and exit, eg. domain switch, interrupts, timer queues, etc.
So just taking a pair of timestamps is not likely to have the
desired result.

I too am interested in a similar measurement (for a specific hypercall),
so if there IS a way to do this with reasonable accuracy, please
correct me.

> On Wed, Oct 15, 2008 at 3:12 AM, Tommy Huang 
> <nbp0204@xxxxxxxxx> wrote:
> > Hi all,
> >
> > I am wondering how to measure the performance of hypercalls.
> > For example, how many X86 instructions are executed in Xen 
> when you issue a
> > hypercall.
> > Also, how to get the frequency of hypercalls which is that how many
> > hypercalls have been issued during a period of time?
> > Thanks in advance.
> >
> > - Nb
> >
> > _______________________________________________
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> > Xen-devel@xxxxxxxxxxxxxxxxxxx
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> >
> >
> 
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