snb_idle.c

/*
 *  (C) 2010,2011       Thomas Renninger <trenn@suse.de>, Novell Inc.
 *
 *  Licensed under the terms of the GNU GPL License version 2.
 *
 *  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_C2_RESIDENCY	0x60D
#define MSR_PKG_C7_RESIDENCY	0x3FA
#define MSR_CORE_C7_RESIDENCY	0x3FE

#define MSR_TSC	0x10

enum intel_snb_id { C7 = 0, PC2, PC7, SNB_CSTATE_COUNT, TSC = 0xFFFF };

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

static cstate_t snb_cstates[SNB_CSTATE_COUNT] = {
	{
		.name			= "C7",
		.desc			= N_("Processor Core C7"),
		.id			= C7,
		.range			= RANGE_CORE,
		.get_count_percent	= snb_get_count_percent,
	},
	{
		.name			= "PC2",
		.desc			= N_("Processor Package C2"),
		.id			= PC2,
		.range			= RANGE_PACKAGE,
		.get_count_percent	= snb_get_count_percent,
	},
	{
		.name			= "PC7",
		.desc			= N_("Processor Package C7"),
		.id			= PC7,
		.range			= RANGE_PACKAGE,
		.get_count_percent	= snb_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[SNB_CSTATE_COUNT];
static unsigned long long *current_count[SNB_CSTATE_COUNT];
/* valid flag for all CPUs. If a MSR read failed it will be zero */
static int *is_valid;

static int snb_get_count(enum intel_snb_id id, unsigned long long *val,
			unsigned int cpu)
{
	int msr;

	switch (id) {
	case C7:
		msr = MSR_CORE_C7_RESIDENCY;
		break;
	case PC2:
		msr = MSR_PKG_C2_RESIDENCY;
		break;
	case PC7:
		msr = MSR_PKG_C7_RESIDENCY;
		break;
	case TSC:
		msr = MSR_TSC;
		break;
	default:
		return -1;
	};
	if (read_msr(cpu, msr, val))
		return -1;
	return 0;
}

static int snb_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",
		snb_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",
	       snb_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 snb_start(void)
{
	int num, cpu;
	unsigned long long val;

	for (num = 0; num < SNB_CSTATE_COUNT; num++) {
		for (cpu = 0; cpu < cpu_count; cpu++) {
			snb_get_count(num, &val, cpu);
			previous_count[num][cpu] = val;
		}
	}
	snb_get_count(TSC, &tsc_at_measure_start, 0);
	return 0;
}

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

	snb_get_count(TSC, &tsc_at_measure_end, 0);

	for (num = 0; num < SNB_CSTATE_COUNT; num++) {
		for (cpu = 0; cpu < cpu_count; cpu++) {
			is_valid[cpu] = !snb_get_count(num, &val, cpu);
			current_count[num][cpu] = val;
		}
	}
	return 0;
}

struct cpuidle_monitor intel_snb_monitor;

static struct cpuidle_monitor *snb_register(void)
{
	int num;

	if (cpupower_cpu_info.vendor != X86_VENDOR_INTEL
	    || cpupower_cpu_info.family != 6)
		return NULL;

	switch (cpupower_cpu_info.model) {
	case 0x2A: /* SNB */
	case 0x2D: /* SNB Xeon */
	case 0x3A: /* IVB */
	case 0x3E: /* IVB Xeon */
	case 0x3C: /* HSW */
	case 0x3F: /* HSW */
	case 0x45: /* HSW */
	case 0x46: /* HSW */
		break;
	default:
		return NULL;
	}

	is_valid = calloc(cpu_count, sizeof(int));
	for (num = 0; num < SNB_CSTATE_COUNT; num++) {
		previous_count[num] = calloc(cpu_count,
					sizeof(unsigned long long));
		current_count[num]  = calloc(cpu_count,
					sizeof(unsigned long long));
	}
	intel_snb_monitor.name_len = strlen(intel_snb_monitor.name);
	return &intel_snb_monitor;
}

void snb_unregister(void)
{
	int num;
	free(is_valid);
	for (num = 0; num < SNB_CSTATE_COUNT; num++) {
		free(previous_count[num]);
		free(current_count[num]);
	}
}

struct cpuidle_monitor intel_snb_monitor = {
	.name			= "SandyBridge",
	.hw_states		= snb_cstates,
	.hw_states_num		= SNB_CSTATE_COUNT,
	.start			= snb_start,
	.stop			= snb_stop,
	.do_register		= snb_register,
	.unregister		= snb_unregister,
	.needs_root		= 1,
	.overflow_s		= 922000000 /* 922337203 seconds TSC overflow
					       at 20GHz */
};
#endif /* defined(__i386__) || defined(__x86_64__) */