Re: [Xen-devel] High CPU temp, suspend problem - xen 4.1.5-pre, linux 3.7.x

[Ben Guthro <ben@xxxxxxxxxx>]

On Tue, Apr 16, 2013 at 1:19 AM, Ben Guthro <ben@xxxxxxxxxx> wrote:
> On Tue, Apr 16, 2013 at 12:51 AM, konrad wilk <konrad.wilk@xxxxxxxxxx> wrote:
>>
>>>> 3. ACPI C-states are only present for CPU0 (after resume of course),
>>>> fixed by
>>>> "xen: Re-upload processor PM data to hypervisor after S3" patch by Ben,
>>>> but it
>>>> isn't in upstream linux (nor Konrad's acpi-s3 branches).
>>>
>>> I don't recall seeing any ACK / NAK from Konrad on this.
>>>
>>> Original post:
>>> https://patchwork.kernel.org/patch/2033981/
>>>
>>> Konrad - do you have any thoughts about incorporating this into a
>>> future merge window?
>>
>>
>> Hey Ben,
>> I seem to have missed it.
>> I think the patch is missing a change to pr_backup->acpi_id = i, otherwise
>> it would resend
>> the C-states with the same APIC ID. Also the upstream version does
>> kfree(pr_backup) at some point.
>
> Hmm. I'll look into this, and re-submit.

At the risk of seeming a bit dim, could you elaborate a bit here?
I'm looking at the function again, and perhaps I'm missing something.

Since xen_acpi_processor_resume() was a subset of what was done in
xen_acpi_processor_init() - I trimmed a number of things unused in the
functionality I was using. This included the pr_backup related things
(both alloc & free)

I'm not seeing exactly what you are suggesting I am missing, if I
don't even have a pr_backup. This usually means I overlooked something
embarrassingly obvious. If you would be so kind as to point this out
so I can slap my forehead, I'd appreciate it.

Thanks
Ben



>
>>
>> But more importantly, do you know why it is needed? Is Xen hypervisor
>> "loosing" this information because they go offline and then they are onlined
>> again?
>
> It was a while ago...the first of a number of 4.2 S3 related
> performance issues that we chasing reports from users / automated QA
> that the end result was "slow performance on S3 in XP"
>
> As it turns out - this didn't fix the performance problem...but it
> also didn't seem right.
>
> I'm not sure if it is because the non-boot cpus are offlined...but it
> would seem to make logical sense.
>
> Ben

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