[PATCH v4 13/15] perf arm_spe: Refactor arm_spe__get_metadata_by_cpu()

[James Clark]

On 31/07/2025 2:25 pm, Leo Yan wrote:
> Handle "CPU=-1" (per-thread mode) in the arm_spe__get_metadata_by_cpu()
> function. As a result, the function is more general and will be invoked
> by a sequential change.
> 
> Signed-off-by: Leo Yan <leo.yan at arm.com>
> ---
>   tools/perf/util/arm-spe.c | 55 ++++++++++++++++++++++-------------------------
>   1 file changed, 26 insertions(+), 29 deletions(-)
> 
> diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
> index 2ac10b8008527a066c9b2f67a22eb8511af9239a..3c32b9bc9c983370e37d871adeaa610bf5905c1d 100644
> --- a/tools/perf/util/arm-spe.c
> +++ b/tools/perf/util/arm-spe.c
> @@ -317,15 +317,38 @@ static int arm_spe_set_tid(struct arm_spe_queue *speq, pid_t tid)
>   	return 0;
>   }
>   
> -static u64 *arm_spe__get_metadata_by_cpu(struct arm_spe *spe, u64 cpu)
> +static u64 *arm_spe__get_metadata_by_cpu(struct arm_spe *spe, int cpu)
>   {
> +	struct perf_cpu_map *cpus;
> +	struct perf_cpu perf_cpu;
>   	u64 i;
>   
>   	if (!spe->metadata)
>   		return NULL;
>   
> +	/* CPU ID is -1 for per-thread mode */
> +	if (cpu < 0) {
> +		/*
> +		 * On the heterogeneous system, due to CPU ID is -1,
> +		 * cannot confirm the data source packet is supported.
> +		 */
> +		if (!spe->is_homogeneous)
> +			return NULL;
> +
> +		cpus = perf_pmus__find_by_type(spe->pmu_type)->cpus;
> +		if (!cpus)
> +			return NULL;
> +
> +		/* In a homogeneous system, fetch the first CPU in the map. */
> +		perf_cpu = perf_cpu_map__cpu(cpus, 0);
> +		if (perf_cpu.cpu == -1)
> +			return NULL;
> +
> +		cpu = perf_cpu.cpu;
> +	}
> +
>   	for (i = 0; i < spe->metadata_nr_cpu; i++)
> -		if (spe->metadata[i][ARM_SPE_CPU] == cpu)
> +		if (spe->metadata[i][ARM_SPE_CPU] == (u64)cpu)
>   			return spe->metadata[i];
>   
>   	return NULL;
> @@ -914,9 +937,6 @@ static bool arm_spe__synth_ds(struct arm_spe_queue *speq,
>   			      union perf_mem_data_src *data_src)
>   {
>   	struct arm_spe *spe = speq->spe;
> -	struct perf_cpu_map *cpus;
> -	struct perf_cpu perf_cpu;
> -	int16_t cpu_nr;
>   	u64 *metadata = NULL;
>   	u64 midr;
>   	unsigned int i;
> @@ -929,30 +949,7 @@ static bool arm_spe__synth_ds(struct arm_spe_queue *speq,
>   		cpuid = perf_env__cpuid(perf_session__env(spe->session));
>   		midr = strtol(cpuid, NULL, 16);
>   	} else {
> -		/* CPU ID is -1 for per-thread mode */
> -		if (speq->cpu < 0) {
> -			/*
> -			 * On the heterogeneous system, due to CPU ID is -1,
> -			 * cannot confirm the data source packet is supported.
> -			 */
> -			if (!spe->is_homogeneous)
> -				return false;
> -
> -			cpus = perf_pmus__find_by_type(spe->pmu_type)->cpus;
> -			if (!cpus)
> -				return false;
> -
> -			/* In a homogeneous system, fetch the first CPU in the map. */
> -			perf_cpu = perf_cpu_map__cpu(cpus, 0);
> -			if (perf_cpu.cpu == -1)
> -				return false;
> -
> -			cpu_nr = perf_cpu.cpu;
> -		} else {
> -			cpu_nr = speq->cpu;
> -		}
> -
> -		metadata = arm_spe__get_metadata_by_cpu(spe, cpu_nr);
> +		metadata = arm_spe__get_metadata_by_cpu(spe, speq->cpu);
>   		if (!metadata)
>   			return false;
>   
> 

Reviewed-by: James Clark <james.clark at linaro.org>