[PATCH] perf/arm-cmn: Permit more exhaustive groups

[Will Deacon]

[+ Ilkka for comments/testing]

On Wed, Dec 11, 2024 at 07:04:58PM +0000, Robin Murphy wrote:
> The group validation logic still somewhat assumes the original CMN-600
> case of events counting globally, such that if one tries to group 9
> events where the first 8 target a single DTC domain, the 9th will be
> rejected because *a* DTC domain is full, even though it might only
> target other non-overlapping domains and thus still be schedulable.
> Improve matters by only counting the DTCs that the new event actually
> needs (as arm_cmn_val_add_event() was already clever enough to do).
> 
> Signed-off-by: Robin Murphy <robin.murphy at arm.com>
> ---
>  drivers/perf/arm-cmn.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
> index edefb51ac90a..b49e353e10ab 100644
> --- a/drivers/perf/arm-cmn.c
> +++ b/drivers/perf/arm-cmn.c
> @@ -1779,8 +1779,8 @@ static int arm_cmn_validate_group(struct arm_cmn *cmn, struct perf_event *event)
>  		goto done;
>  	}
>  
> -	for (i = 0; i < CMN_MAX_DTCS; i++)
> -		if (val->dtc_count[i] == CMN_DT_NUM_COUNTERS)
> +	for_each_hw_dtc_idx(hw, dtc, idx)
> +		if (val->dtc_count[dtc] == CMN_DT_NUM_COUNTERS)
>  			goto done;
>  
>  	for_each_hw_dn(hw, dn, i) {
> -- 
> 2.39.2.101.g768bb238c484.dirty
>