nhm_idle.c

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/*
 *  (C) 2010,2011       Thomas Renninger <[email protected]>, Novell Inc.
 *
 *  Licensed under the terms of the GNU GPL License version 2.
 *
 *  Based on Len Brown's <[email protected]> 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, 0);

    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, 0);
    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, 0);

    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, 0);
    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,
    .needs_root     = 1,
    .overflow_s     = 922000000 /* 922337203 seconds TSC overflow
                           at 20GHz */
};
#endif