arm64 sched_clock cpu accounting

[m.smarduch@samsung.com (Mario Smarduch)]

On 12/3/2015 1:29 AM, Will Deacon wrote:
> On Wed, Dec 02, 2015 at 03:42:10PM -0800, Mario Smarduch wrote:
>> On 12/2/2015 10:07 AM, Christoffer Dall wrote:
>>> On Wed, Nov 18, 2015 at 06:20:03PM -0800, Mario Smarduch wrote:
>>>> Also with tick accounting enabled, and periodic timer HZ set to 1000 no irq time
>>>> is reported. That's with running a ping flood - 1200 int/s, not sure why
>>>> wouldn't any irq time be reported? The other two modes report irq time as expected.
>>>>
>>>> On 11/18/2015 11:46 AM, Mario Smarduch wrote:
>>>>> Hello,
>>>>>   I noticed sched clock accounting can be enabled when arch-timer is
>>>>> initialized. But arm64 doesn't appear to have 'HAVE_IRQ_TIME_ACCOUNTING'
>>>>> selected (as of mainline 4.4-rc1) and IRQ_TIME_ACCOUNTING can't be selected.
>>>>> After adding it to arch/arm64/Kconfig, option appears to work fine. Depending on
>>>>> need all accounting options are fine, but irq time accounting appears to be most
>>>>> preferable.
>>>>>
>>>>> Any thoughts? Is it fine to enable it?
>>>>>
>>> Is any of this related to KVM?
>>
>> Indirectly, given the guest should yield same results. To be on the safe side I
>> ran the guest in all combinations (7) to confirm that's the case.
>>
>> Also verified that guest time on host appears fine in all these configurations.
>> It takes extra effort to get the guest time as opposed to other modes.
> 
> I can take this via the arm64 tree (where it's queued, but I've not pushed
> anything yet).
> 
> Will

Great thanks.
>