[PATCH 0/8] Support for 24x7 hcall interface version 2

[Michael Ellerman]

Thiago Jung Bauermann <bauerman at linux.vnet.ibm.com> writes:

> Michael Ellerman <mpe at ellerman.id.au> writes:
>> Thiago Jung Bauermann <bauerman at linux.vnet.ibm.com> writes:
>>> The hypervisor interface to access 24x7 performance counters (which collect
>>> performance information from system power on to system power off) has been
>>> extended in POWER9 adding new fields to the request and result element
>>> structures.
>>>
>>> Also, results for some domains now return more than one result element and
>>> those need to be added to get a total count.
>>>
>>> The first two patches fix bugs in the existing code. The following 4
>>> patches are code improvements and the last two finally implement support
>>> for the changes in POWER9 described above.
>>>
>>> POWER8 systems only support version 1 of the interface, while POWER9
>>> systems only support version 2. I tested these patches on POWER8 to verify
>>> that there are no regressions, and also on POWER9 DD1.
>>
>> Where is version 2 documented?
>
> Only in an internal specification.

Presumably a PAPR ACR, what's the title? And is it approved/accepted?

>> And what happens when we boot on a POWER9 in POWER8 compatibility mode?
>
> It will still use version 2 of the API, and still require aggregation of
> result elements. Does this mean that hv_24x7_init should check
> cur_cpu_spec->oprofile_cpu_type for "ppc64/power9" instead of
> cpu_has_feature(CPU_FTR_ARCH_300)?

Yes.

cheers