Re: [PATCH V1 2/6] cpufreq: amd-pstate: Enable AMD Pstate Preferred Core Supporting.

On Tue, Aug 08, 2023 at 04:09:57PM +0800, Meng Li wrote:

+static int amd_pstate_get_highest_perf(int cpu, u64 *highest_perf) +{

•   int ret;
  

•   if (boot_cpu_has(X86_FEATURE_CPPC)) {
  

•           u64 cap1;
  

•           ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1, &cap1);
  

•           if (ret)
  

•                   return ret;
  

•           WRITE_ONCE(*highest_perf, AMD_CPPC_HIGHEST_PERF(cap1));
  

•   } else {
  

•           ret = cppc_get_highest_perf(cpu, highest_perf);
  

•   }
  

•   return (ret);
  

+}

+static void amd_pstate_init_prefcore(void) +{

• int cpu, ret;
• u64 highest_perf;
• if (no_prefcore)

• return;
  

• for_each_possible_cpu(cpu) {

• ret = amd_pstate_get_highest_perf(cpu, &highest_perf);
  

• if (ret)
  

• 	break;
  

So what is the intended behaviour when online != possible ?

• sched_set_itmt_core_prio(highest_perf, cpu);
  

• }
• /*

• * This code can be run during CPU online under the
  

• * CPU hotplug locks, so sched_set_amd_prefcore_support()
  

• * cannot be called from here.  Queue up a work item
  

• * to invoke it.
  

• */
  

• schedule_work(&sched_prefcore_work);

+}