[v3 13/15] tools/perf: Add perf tools support for extended register capability in powerpc

[Athira Rajeev]

> On 24-Jul-2020, at 4:32 PM, Ravi Bangoria <ravi.bangoria at linux.ibm.com> wrote:
> 
> Hi Athira,
> 
> On 7/17/20 8:08 PM, Athira Rajeev wrote:
>> From: Anju T Sudhakar <anju at linux.vnet.ibm.com>
>> Add extended regs to sample_reg_mask in the tool side to use
>> with `-I?` option. Perf tools side uses extended mask to display
>> the platform supported register names (with -I? option) to the user
>> and also send this mask to the kernel to capture the extended registers
>> in each sample. Hence decide the mask value based on the processor
>> version.
>> Currently definitions for `mfspr`, `SPRN_PVR` are part of
>> `arch/powerpc/util/header.c`. Move this to a header file so that
>> these definitions can be re-used in other source files as well.
> 
> It seems this patch has a regression.
> 
> Without this patch:
> 
>  $ sudo ./perf record -I
>  ^C[ perf record: Woken up 1 times to write data ]
>  [ perf record: Captured and wrote 0.458 MB perf.data (318 samples) ]
> 
> With this patch:
> 
>  $ sudo ./perf record -I
>  Error:
>  dummy:HG: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'


Hi Ravi,

Thanks for reviewing this patch and also testing. The above issue happens since
commit 0a892c1c9472 ("perf record: Add dummy event during system wide synthesis”) which adds a dummy event.

The fix for this issue is currently discussed here:  https://lkml.org/lkml/2020/7/19/413
So once this fix is in, the issue will be resolved.

Thanks
Athira

> 
> Ravi