Re: [Xen-devel] some questions about Xenoprof

["Niraj Tolia" <ntolia@xxxxxxxxx>]

On Sun, Jan 4, 2009 at 7:32 PM, weiming <zephyr.zhao@xxxxxxxxx> wrote:
> Hi,
>
> I want to use Xenoprof to monitors some system-wide events (like L2 misses
> etc).
>
> 1. I'm using Xen 3.3. I guess I don't need to patch it as I find that a
> hypercall and some source codes related to xenoprof are already there. So I
> just downloaded the patch against oprofile. After that, when I run opcontrol
> --help, I found that "--xen" was listed as an option. So I think my
> installation should be OK.
>
> 2. I will run some workloads on domU. What I want to monitor is the
> system-wide event counts like L2_LINES_IN. What should I do? Is running
> "opcontrol --start --no-vmlinux --event=XXXX:YYYY:ZZZZ" on dom0 enough? Need
> I specify "--passive-domains" or "--active-domains" ?
>
> 3. I'm running the system on a muliti-core machine. Can Xenoprof list the
> event counters per core?


Not per physical core. However, from what I understand, xenoprof can
list the event counters per VCPU if you use the --separate=cpu option.
So, you could pin the VCPUs to cores if that is what you really want.

Second, the current version of xenoprof has a bug that prevents it
from correctly collecting per-VCPU info. Renato (cc-ed) should have a
patch to fix this though.

Cheers,
Niraj

-- 
Niraj Tolia, Researcher, HP Labs
http://www.hpl.hp.com/personal/Niraj_Tolia/

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