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Re: [Xen-devel] How to make tracking CPU cache-miss on Xen?

On Tue, Dec 12, 2017 at 12:30 AM, George Dunlap <dunlapg@xxxxxxxxx> wrote:
On Mon, Dec 11, 2017 at 3:05 PM, Boris Ostrovsky
<boris.ostrovsky@xxxxxxxxxx> wrote:
> On 12/11/2017 09:36 AM, Meng Xu wrote:
>> On Mon, Dec 11, 2017 at 8:14 AM, Minjun Hong <nickeysgo@xxxxxxxxx> wrote:
>>> Thanks for your answer, George.
>>> What I want ultimately is cache misses from the guest, but even I could not get the cache misses from dom0 also.
>>> That's why I'm confused as I know, it should be possible to get cache-misses from dom0 (is it right??).
>>> I already enabled CONFIG_XEN_HAVE_VPMU of current kernel to get cache misses. Is there anything what I miss during Xen install?
>> If this is for a research project, I would suggest you to write your
>> own code to monitor the cache misses for domU. This could be faster,
>> since it's not complicated to do so.
>> IIRC, PMU in Xen can only monitor the cache misses when VCPUs are
>> pinned to cores.
> Counters are virtualized for guests (including dom0) so I am not sure
> pinning is required. Pinning is only needed when you try to collect
> counters for full system.
> OTOH, when a VCPU is migrated you start running with a new cache,
> something to keep in mind.

Well if his goal was to measure cache misses based on different Xen
scheduling algorithms, that might be the point. :-)

Minjun: BTW, it's standard on this list to quote inline (as I'm
doing), rather than top-posting (having your reply at the top and the
original mail entirely beneath it).


Thanks to your help, finally, I resolve the problem.
I could have access to VPMU and I successfully estimated performance of my work.

And, I'm sorry for violation of standard for this list.
I will pay attention to this point in the future.

I'd like to appreciate your help again.

Minjun Hong
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