Re: [PATCH 2/3] arch_topology: obtain cpu capacity using information from CPPC

From: Valentin Schneider
Date: Tue May 18 2021 - 09:12:20 EST


On 14/05/21 10:53, Ionela Voinescu wrote:
> +#ifdef CONFIG_ACPI_CPPC_LIB
> +#include <acpi/cppc_acpi.h>
> +
> +void init_cpu_capacity_cppc(void)
> +{
> + struct cppc_perf_caps perf_caps;
> + int cpu;
> +
> + if (likely(acpi_disabled || !acpi_cpc_valid()))
> + return;
> +
> + raw_capacity = kcalloc(num_possible_cpus(), sizeof(*raw_capacity),
> + GFP_KERNEL);

Per the below loop, the memory shouldn't need to be cleared.

> + if (!raw_capacity)
> + return;
> +
> + for_each_possible_cpu(cpu) {
> + if (!cppc_get_perf_caps(cpu, &perf_caps)) {
> + raw_capacity[cpu] = perf_caps.highest_perf;
> + pr_debug("%s: CPU%d cpu_capacity=%u (raw).\n",
> + __func__, cpu, raw_capacity[cpu]);
> + } else {
> + pr_err("%s: CPU%d missing highest performance.\n",
> + __func__, cpu);
> + pr_err("%s: fallback to 1024 for all CPUs\n",
> + __func__);
> + goto exit;
> + }
> + }
> +
> + topology_normalize_cpu_scale();
> + schedule_work(&update_topology_flags_work);
> + pr_debug("%s: cpu_capacity initialization done\n", __func__);
> +
> +exit:
> + free_raw_capacity();
> +}
> +#endif