Quelle  nhm_idle.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  (C) 2010,2011       Thomas Renninger <trenn@suse.de>, Novell Inc.
 *
 *  Based on Len Brown's <lenb@kernel.org> turbostat tool.
 */

#if defined(__i386__) || defined(__x86_64__)

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "helpers/helpers.h"
#include "idle_monitor/cpupower-monitor.h"

#define MSR_PKG_C3_RESIDENCY 0x3F8
#define MSR_PKG_C6_RESIDENCY 0x3F9
#define MSR_CORE_C3_RESIDENCY 0x3FC
#define MSR_CORE_C6_RESIDENCY 0x3FD

#define MSR_TSC 0x10

#define NHM_CSTATE_COUNT 4

enum intel_nhm_id { C3 = 0, C6, PC3, PC6, TSC = 0xFFFF };

static int nhm_get_count_percent(unsigned int self_id, double *percent,
     unsigned int cpu);

static cstate_t nhm_cstates[NHM_CSTATE_COUNT] = {
 {
  .name   = "C3",
  .desc   = N_("Processor Core C3"),
  .id   = C3,
  .range   = RANGE_CORE,
  .get_count_percent = nhm_get_count_percent,
 },
 {
  .name   = "C6",
  .desc   = N_("Processor Core C6"),
  .id   = C6,
  .range   = RANGE_CORE,
  .get_count_percent = nhm_get_count_percent,
 },

 {
  .name   = "PC3",
  .desc   = N_("Processor Package C3"),
  .id   = PC3,
  .range   = RANGE_PACKAGE,
  .get_count_percent = nhm_get_count_percent,
 },
 {
  .name   = "PC6",
  .desc   = N_("Processor Package C6"),
  .id   = PC6,
  .range   = RANGE_PACKAGE,
  .get_count_percent = nhm_get_count_percent,
 },
};

static unsigned long long tsc_at_measure_start;
static unsigned long long tsc_at_measure_end;
static unsigned long long *previous_count[NHM_CSTATE_COUNT];
static unsigned long long *current_count[NHM_CSTATE_COUNT];
/* valid flag for all CPUs. If a MSR read failed it will be zero */
static int *is_valid;

static int nhm_get_count(enum intel_nhm_id id, unsigned long long *val,
   unsigned int cpu)
{
 int msr;

 switch (id) {
 case C3:
  msr = MSR_CORE_C3_RESIDENCY;
  break;
 case C6:
  msr = MSR_CORE_C6_RESIDENCY;
  break;
 case PC3:
  msr = MSR_PKG_C3_RESIDENCY;
  break;
 case PC6:
  msr = MSR_PKG_C6_RESIDENCY;
  break;
 case TSC:
  msr = MSR_TSC;
  break;
 default:
  return -1;
 }
 if (read_msr(cpu, msr, val))
  return -1;

 return 0;
}

static int nhm_get_count_percent(unsigned int id, double *percent,
     unsigned int cpu)
{
 *percent = 0.0;

 if (!is_valid[cpu])
  return -1;

 *percent = (100.0 *
  (current_count[id][cpu] - previous_count[id][cpu])) /
  (tsc_at_measure_end - tsc_at_measure_start);

 dprint("%s: previous: %llu - current: %llu - (%u)\n",
  nhm_cstates[id].name, previous_count[id][cpu],
  current_count[id][cpu], cpu);

 dprint("%s: tsc_diff: %llu - count_diff: %llu - percent: %2.f (%u)\n",
        nhm_cstates[id].name,
        (unsigned long long) tsc_at_measure_end - tsc_at_measure_start,
        current_count[id][cpu] - previous_count[id][cpu],
        *percent, cpu);

 return 0;
}

static int nhm_start(void)
{
 int num, cpu;
 unsigned long long dbg, val;

 nhm_get_count(TSC, &tsc_at_measure_start, base_cpu);

 for (num = 0; num < NHM_CSTATE_COUNT; num++) {
  for (cpu = 0; cpu < cpu_count; cpu++) {
   is_valid[cpu] = !nhm_get_count(num, &val, cpu);
   previous_count[num][cpu] = val;
  }
 }
 nhm_get_count(TSC, &dbg, base_cpu);
 dprint("TSC diff: %llu\n", dbg - tsc_at_measure_start);
 return 0;
}

static int nhm_stop(void)
{
 unsigned long long val;
 unsigned long long dbg;
 int num, cpu;

 nhm_get_count(TSC, &tsc_at_measure_end, base_cpu);

 for (num = 0; num < NHM_CSTATE_COUNT; num++) {
  for (cpu = 0; cpu < cpu_count; cpu++) {
   is_valid[cpu] |= !nhm_get_count(num, &val, cpu);
   current_count[num][cpu] = val;
  }
 }
 nhm_get_count(TSC, &dbg, base_cpu);
 dprint("TSC diff: %llu\n", dbg - tsc_at_measure_end);

 return 0;
}

struct cpuidle_monitor intel_nhm_monitor;

struct cpuidle_monitor *intel_nhm_register(void)
{
 int num;

 if (cpupower_cpu_info.vendor != X86_VENDOR_INTEL)
  return NULL;

 if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_INV_TSC))
  return NULL;

 if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_APERF))
  return NULL;

 /* Free this at program termination */
 is_valid = calloc(cpu_count, sizeof(int));
 for (num = 0; num < NHM_CSTATE_COUNT; num++) {
  previous_count[num] = calloc(cpu_count,
     sizeof(unsigned long long));
  current_count[num]  = calloc(cpu_count,
     sizeof(unsigned long long));
 }

 intel_nhm_monitor.name_len = strlen(intel_nhm_monitor.name);
 return &intel_nhm_monitor;
}

void intel_nhm_unregister(void)
{
 int num;

 for (num = 0; num < NHM_CSTATE_COUNT; num++) {
  free(previous_count[num]);
  free(current_count[num]);
 }
 free(is_valid);
}

struct cpuidle_monitor intel_nhm_monitor = {
 .name   = "Nehalem",
 .hw_states_num  = NHM_CSTATE_COUNT,
 .hw_states  = nhm_cstates,
 .start   = nhm_start,
 .stop   = nhm_stop,
 .do_register  = intel_nhm_register,
 .unregister  = intel_nhm_unregister,
 .flags.needs_root = 1,
 .overflow_s  = 922000000 /* 922337203 seconds TSC overflow
       at 20GHz */
};
#endif