Re: [Xen-devel] How to get the accurate physical CPU utilization in Dom0?

[Bei Guan <gbtju85@xxxxxxxxx>]

Hi,

Thank you for all your advice. I have another one question.

How does the Xen scheduler map a vcpu to a physical CPU, if the host has multi-cores? Is there any rules in the map? Or the map is irregular?

Thank you for your time.

2014-02-27 23:40 GMT+08:00 Roger Pau Monné <roger.pau@xxxxxxxxxx>:

On 27/02/14 16:06, Bei Guan wrote:
> Hi,
>
> I run a PV DomU with 1 vcpu on Xen. I pin the vcpu to a physical CPU
> core, such as core 3. Then, I run a cpu-bound process in DomU and the
> vcpu utilization is 100% (got it with "xentop" in Dom0).
> However, when I use "top" in Dom0 to see the physical CPU utilization,
> the CPU core 3 utilization is zero or less than 1%. The utilization
> expected of CPU core 3 is also 100% like the vcpu. Is it? Why I cannot
> get the accurate physical CPU utilization with "top" command in Dom0?

top in Dom0 will only show CPU utilization of Dom0 (Xen is not a type 2
hypervisor, so Dom0 is no different than any other DomU in this aspect),
if you want to see CPU utilization of all domains you should use xl top
(xentop).

Roger.

--
Best Regards,

Bei Guan

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