Re: [Xen-devel] [BUG] Linux process vruntime accounting in Xen

[Juergen Gross <jgross@xxxxxxxx>]

On 18/05/16 18:09, Tony S wrote:
> On Wed, May 18, 2016 at 8:57 AM, Dario Faggioli
> <dario.faggioli@xxxxxxxxxx> wrote:
>> On Wed, 2016-05-18 at 14:24 +0200, Juergen Gross wrote:
>>> On 17/05/16 11:33, George Dunlap wrote:
>>>>> Looks like CONFIG_PARAVIRT_TIME_ACCOUNTING is used for adjusting
>>>>> process
>>>>> times. KVM uses it but Xen doesn't.
>>>> Is someone on the Linux side going to put this on their to-do list
>>>> then? :-)
>>>
>>> Patch sent.
>>>
>> Yep, seen it, thanks.
>>
>>> Support was already existing for arm.
>>>
>> Yes!! I remember Stefano talking about introducing it, and that was
>> also why I thought we had it already since long time on x86.
>>
>> Well, anyway... :-)
>>
>>> What is missing is support for
>>> paravirt_steal_rq_enabled which requires to be able to read the
>>> stolen
>>> time of another cpu. This can't work today as accessing another cpu's
>>> vcpu_runstate_info isn't possible without risking inconsistent data.
>>> I plan to add support for this, too, but this will require adding
>>> another hypercall to map a modified vcpu_runstate_info containing an
>>> indicator for an ongoing update of the data.
>>>
>> Understood.
>>
>> So, Tony, up for trying again your workload with this patch applied to
>> Linux?
>>
>> Most likely, it _won't_ fix all the problems you're seeing, but I'm
>> curious to see if it helps.
> 
> Hi Dario,
> 
> I did not see the patch. Can you please send me the patch and I will
> try to test it later.

Here is an updated version.


Juergen

Attachment: v2-0001-xen-add-steal_clock-support-on-x86.patch
Description: Text Data

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