Re: [PATCH] powerpc/perf: Exclude pmc5/6 from the irrelevant PMU group constraints

2020-09-17 Thread Athira Rajeev 



> On 17-Sep-2020, at 5:43 PM, Michael Ellerman  wrote:
> 
> Athira Rajeev  writes:
>> PMU counter support functions enforces event constraints for group of
>> events to check if all events in a group can be monitored. Incase of
>> event codes using PMC5 and PMC6 ( 500fa and 600f4 respectively ),
>> not all constraints are applicable, say the threshold or sample bits.
>> But current code includes pmc5 and pmc6 in some group constraints (like
>> IC_DC Qualifier bits) which is actually not applicable and hence results
>> in those events not getting counted when scheduled along with group of
>> other events. Patch fixes this by excluding PMC5/6 from constraints
>> which are not relevant for it.
>> 
>> Fixes: 7ffd948 ('powerpc/perf: factor out power8 pmu functions')
>> Signed-off-by: Athira Rajeev 
>> ---
>> arch/powerpc/perf/isa207-common.c | 4 
>> 1 file changed, 4 insertions(+)
>> 
>> diff --git a/arch/powerpc/perf/isa207-common.c 
>> b/arch/powerpc/perf/isa207-common.c
>> index 964437a..186fad8 100644
>> --- a/arch/powerpc/perf/isa207-common.c
>> +++ b/arch/powerpc/perf/isa207-common.c
>> @@ -288,6 +288,9 @@ int isa207_get_constraint(u64 event, unsigned long 
>> *maskp, unsigned long *valp)
>> 
>>  mask  |= CNST_PMC_MASK(pmc);
>>  value |= CNST_PMC_VAL(pmc);
>> +
>> +if (pmc >= 5)
>> +goto ebb_bhrb;
> 
> This is fairly subtle. Can you please put a block comment above the if
> explaining in a few lines what's going on.

Hi Michael,

Sure, I will include a comment explaining the change in V2.

Thanks
Athira
> 
> cheers

Re: [PATCH] powerpc/perf: Exclude pmc5/6 from the irrelevant PMU group constraints

2020-09-17 Thread Michael Ellerman 
Athira Rajeev  writes:
> PMU counter support functions enforces event constraints for group of
> events to check if all events in a group can be monitored. Incase of
> event codes using PMC5 and PMC6 ( 500fa and 600f4 respectively ),
> not all constraints are applicable, say the threshold or sample bits.
> But current code includes pmc5 and pmc6 in some group constraints (like
> IC_DC Qualifier bits) which is actually not applicable and hence results
> in those events not getting counted when scheduled along with group of
> other events. Patch fixes this by excluding PMC5/6 from constraints
> which are not relevant for it.
>
> Fixes: 7ffd948 ('powerpc/perf: factor out power8 pmu functions')
> Signed-off-by: Athira Rajeev 
> ---
>  arch/powerpc/perf/isa207-common.c | 4 
>  1 file changed, 4 insertions(+)
>
> diff --git a/arch/powerpc/perf/isa207-common.c 
> b/arch/powerpc/perf/isa207-common.c
> index 964437a..186fad8 100644
> --- a/arch/powerpc/perf/isa207-common.c
> +++ b/arch/powerpc/perf/isa207-common.c
> @@ -288,6 +288,9 @@ int isa207_get_constraint(u64 event, unsigned long 
> *maskp, unsigned long *valp)
>  
>   mask  |= CNST_PMC_MASK(pmc);
>   value |= CNST_PMC_VAL(pmc);
> +
> + if (pmc >= 5)
> + goto ebb_bhrb;

This is fairly subtle. Can you please put a block comment above the if
explaining in a few lines what's going on.

cheers