Re: Strange interdependace between domains

[Juergen Gross <juergen.gross@ts.fujitsu.com>]

On 18.02.2014 19:06, Dario Faggioli wrote:
> On mar, 2014-02-18 at 12:58 -0500, Don Slutz wrote:
>>>> root@smartin-xen:~# xl cpupool-list -c
>>>> Name               CPU list
>>>> Pool-0             0,1,2
>>
>> Change to something like:
>>
>>
>> Pool-0             0,1,2 (and part of 3)
>>
> This would be cool, and I personally would be all for it... but it
> perhaps will not be that clear at pointing the user to think to
> hyperthreading. :-P
>
>> Or add:
>>
>> Warning: cpupool's share hyperthreaded cpus.
>>
> While this one, although a bit more "boring" than the above, would
> probably be something quite valuable to have!
>
> I can only think of rather expensive ways of implementing it, involving
> going through all the cpupools and, for each cpupool, through all its
> cpus and check the topology relationships, but perhaps there are others
> (I'll think harder).
>
> Also, we are certainly not talking about hot paths.
>
> Juergen?

Adding some information like this would be nice, indeed. But I think we should
not limit this to just hyperthreads. There are more levels of shared resources,
like caches or memory interfaces on the same socket. In case we want to add
information about potential performance influences due to shared resources, we
should be more generic.

And what about some NUMA information? Wouldn't it be worthwhile to show memory
locality information as well? This should be considered to be displayed by
"xl list", too.


Juergen

-- 
Juergen Gross                 Principal Developer Operating Systems
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