On 10/05/2019 12:29, Dario Faggioli wrote:
> On Fri, 2019-05-10 at 11:00 +0200, Juergen Gross wrote:
>> On 10/05/2019 10:53, Jan Beulich wrote:
>>>>>> On 08.05.19 at 16:36, <jgr...@suse.com> wrote:
>>>>
>>>> With sched-gran=core or sched-gran=socket offlining a single cpu
>>>> results
>>>> in moving the complete core or socket to cpupool_free_cpus and
>>>> then
>>>> offlining from there. Only complete cores/sockets can be moved to
>>>> any
>>>> cpupool. When onlining a cpu it is added to cpupool_free_cpus and
>>>> if
>>>> the core/socket is completely online it will automatically be
>>>> added to
>>>> Pool-0 (as today any single onlined cpu).
>>>
>>> Well, this is in line with what was discussed on the call
>>> yesterday, so
>>> I think it's an acceptable initial state to end up in. Albeit, just
>>> for
>>> completeness, I'm not convinced there's no use for "smt-
>>> {dis,en}able"
>>> anymore with core-aware scheduling implemented just in Xen - it
>>> may still be considered useful as long as we don't expose proper
>>> topology to guests, for them to be able to do something similar.
>>
>> As the extra complexity for supporting that is significant I'd like
>> to
>> at least postpone it. And with the (later) introduction of per-
>> cpupool
>> smt on/off I guess this would be even less important.
>>
> I agree.
>
> Isn't it the case that (but note that I'm just thinking out loud here),
> if we make smt= and sched-gran= per-cpupool, the user gains the chance
> to use both, if he/she wants (e.g., for testing)?
Yes.
> If yes, is such a thing valuable enough that it'd it make sense to work
> on that, as a first thing, I mean?
My planned roadmap is:
1. this series
2. scheduler clean-up
3. per-cpupool smt and granularity
> We'd still forbid moving things from pools with different
> configuration, at least at the beginning, of course.
Right, allowing that would be 4.
Juergen
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
