linux/tools/power/cpupower/utils/idle_monitor/nhm_idle.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,
	.needs_root		= 1,
	.overflow_s		= 922000000 /* 922337203 seconds TSC overflow
					       at 20GHz */
};
#endif