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* get CPU idle time?
@ 2006-07-12 20:00 David Carr
  2006-07-12 20:03 ` Rob Gardner
  0 siblings, 1 reply; 3+ messages in thread
From: David Carr @ 2006-07-12 20:00 UTC (permalink / raw)
  To: xen-devel

Whats the best way to get the CPU idle time on xen?  I just want to know
the idle time for the physical CPU.  I'm getting differing results between
xenoprof and xentop (modified to add up all the domains).  Is there
something I can trust?
-DC

^ permalink raw reply	[flat|nested] 3+ messages in thread
* RE: get CPU idle time?
@ 2006-07-12 20:09 Apparao, Padmashree K
  0 siblings, 0 replies; 3+ messages in thread
From: Apparao, Padmashree K @ 2006-07-12 20:09 UTC (permalink / raw)
  To: Rob Gardner, David Carr; +Cc: xen-devel

I have found that xenoprof and xentop match. You have to convert the
samples to utilization. Xenoprof does not give util directly. 

Formula:

[(global_power_event_samples)*sample after value]/sample time ==> will
give events/sec
Then divide this by the clock freq (cpu freq in cycles/sec) that will
give you the cpu util.
Global_power_events per sec / Cycles per sec = utilization

Hope this helps
Thanks
- Padma





-----Original Message-----
From: xen-devel-bounces@lists.xensource.com
[mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of Rob Gardner
Sent: Wednesday, July 12, 2006 1:04 PM
To: David Carr
Cc: xen-devel@lists.xensource.com
Subject: Re: [Xen-devel] get CPU idle time?

David Carr wrote:
> Whats the best way to get the CPU idle time on xen?  I just want to
know
> the idle time for the physical CPU.  I'm getting differing results
between
> xenoprof and xentop (modified to add up all the domains).  Is there
> something I can trust?

Xenmon reports cpu idle time directly. Give it a try and see if it's 
trustworthy.

Rob



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2006-07-12 20:00 get CPU idle time? David Carr
2006-07-12 20:03 ` Rob Gardner
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2006-07-12 20:09 Apparao, Padmashree K

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