RE: [Xen-users] CPU activity: top and xm top

["Petersson, Mats" <Mats.Petersson@xxxxxxx>]

> -----Original Message-----
> From: Igor Chubin [mailto:igor@xxxxxxx] 
> Sent: 11 April 2007 10:33
> To: Petersson, Mats
> Cc: Xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-users] CPU activity: top and xm top
> 
> 
> Mats, 
> 
> thank you for your answer.
> 
> 
> Now I know that domain 0 CPU activity consists of 
> hypervisor activity and domain 0 kernel with its processes.
> 
> You suppose that this 20% (or 14% to be more correct)
> hypervisor spends processing interrupts.
> 
> But my machine is idle.
> It does nothing: it has no network activity and presumable no disk
> activity.
> 
> I wanted to inspect interrupts activity using sar, 
> but without success. Unfortunately sar doesn't report interrupts
> activity under Xen :(
> (May be I can use /proc/interrupts and get information from this
> file? Will it be correct?)

It should be correct as to what Dom0 is doing, it won't show interrupts
that go to Xen but are "hidden" from Dom0 (but I doubt that is many). 
> 
> So my machine is idle but I have 20% of CPU activity for domain 0.
> The question is: How can I get exactly know for what is this 
> 20% spending?
> What tools (or interfaces e.g. /proc files) can I use for this?

Xenoprofile is probably your best bet. 

--
Mats
> 
> 
> ...
> > > I have only domain 0 running. No U-domains at all.
> > > 
> > >     $ sudo xm list
> > >     Name     ID Mem(MiB) VCPUs State  Time(s)
> > >     Domain-0 0  192      2     r----- 184.0
> > > 
> > > How does xm top calculate cpu activity?
> > > Is there any way to access low level information that xm 
> top uses in
> > > its calculations?
> > 
> > Yes there is, but I don't know how (it's been discussed 
> before on Xen
> > Users and/or Xen Devel, so google should be able to find it). 
> > 
> > Xm top is just a python script, and you can get the 
> information that the
> > python-code is fetching from the hypervisor. 
> > 
> 
> I know this.
> But may be somebody have done this already
> and knows where this low-level information lies.
> 
> Ok, I will Google for this.
> 
> 
> -- 
> WBR, i.m.chubin
> 
> 
> 
> 



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