/*
 * turbostat -- show CPU frequency and C-state residency
 * on modern Intel turbo-capable processors.
 *
 * Copyright (c) 2010, Intel Corporation.
 * Len Brown <len.brown@intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/resource.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/time.h>
#include <stdlib.h>
#include <dirent.h>
#include <string.h>
#include <ctype.h>

#define MSR_TSC	0x10
#define MSR_NEHALEM_PLATFORM_INFO	0xCE
#define MSR_NEHALEM_TURBO_RATIO_LIMIT	0x1AD
#define MSR_APERF	0xE8
#define MSR_MPERF	0xE7
#define MSR_PKG_C2_RESIDENCY	0x60D	/* SNB only */
#define MSR_PKG_C3_RESIDENCY	0x3F8
#define MSR_PKG_C6_RESIDENCY	0x3F9
#define MSR_PKG_C7_RESIDENCY	0x3FA	/* SNB only */
#define MSR_CORE_C3_RESIDENCY	0x3FC
#define MSR_CORE_C6_RESIDENCY	0x3FD
#define MSR_CORE_C7_RESIDENCY	0x3FE	/* SNB only */

char *proc_stat = "/proc/stat";
unsigned int interval_sec = 5;	/* set with -i interval_sec */
unsigned int verbose;		/* set with -v */
unsigned int skip_c0;
unsigned int skip_c1;
unsigned int do_nhm_cstates;
unsigned int do_snb_cstates;
unsigned int has_aperf;
unsigned int units = 1000000000;	/* Ghz etc */
unsigned int genuine_intel;
unsigned int has_invariant_tsc;
unsigned int do_nehalem_platform_info;
unsigned int do_nehalem_turbo_ratio_limit;
unsigned int extra_msr_offset;
double bclk;
unsigned int show_pkg;
unsigned int show_core;
unsigned int show_cpu;

int aperf_mperf_unstable;
int backwards_count;
char *progname;
int need_reinitialize;

int num_cpus;

struct counters {
	unsigned long long tsc;		/* per thread */
	unsigned long long aperf;	/* per thread */
	unsigned long long mperf;	/* per thread */
	unsigned long long c1;	/* per thread (calculated) */
	unsigned long long c3;	/* per core */
	unsigned long long c6;	/* per core */
	unsigned long long c7;	/* per core */
	unsigned long long pc2;	/* per package */
	unsigned long long pc3;	/* per package */
	unsigned long long pc6;	/* per package */
	unsigned long long pc7;	/* per package */
	unsigned long long extra_msr;	/* per thread */
	int pkg;
	int core;
	int cpu;
	struct counters *next;
};

struct counters *cnt_even;
struct counters *cnt_odd;
struct counters *cnt_delta;
struct counters *cnt_average;
struct timeval tv_even;
struct timeval tv_odd;
struct timeval tv_delta;

unsigned long long get_msr(int cpu, off_t offset)
{
	ssize_t retval;
	unsigned long long msr;
	char pathname[32];
	int fd;

	sprintf(pathname, "/dev/cpu/%d/msr", cpu);
	fd = open(pathname, O_RDONLY);
	if (fd < 0) {
		perror(pathname);
		need_reinitialize = 1;
		return 0;
	}

	retval = pread(fd, &msr, sizeof msr, offset);
	if (retval != sizeof msr) {
		fprintf(stderr, "cpu%d pread(..., 0x%zx) = %jd\n",
			cpu, offset, retval);
		exit(-2);
	}

	close(fd);
	return msr;
}

void print_header(void)
{
	if (show_pkg)
		fprintf(stderr, "pk");
	if (show_core)
		fprintf(stderr, " cr");
	if (show_cpu)
		fprintf(stderr, " CPU");
	if (do_nhm_cstates)
		fprintf(stderr, "    %%c0 ");
	if (has_aperf)
		fprintf(stderr, " GHz");
	fprintf(stderr, "  TSC");
	if (do_nhm_cstates)
		fprintf(stderr, "    %%c1");
	if (do_nhm_cstates)
		fprintf(stderr, "    %%c3");
	if (do_nhm_cstates)
		fprintf(stderr, "    %%c6");
	if (do_snb_cstates)
		fprintf(stderr, "    %%c7");
	if (do_snb_cstates)
		fprintf(stderr, "  %%pc2");
	if (do_nhm_cstates)
		fprintf(stderr, "  %%pc3");
	if (do_nhm_cstates)
		fprintf(stderr, "  %%pc6");
	if (do_snb_cstates)
		fprintf(stderr, "  %%pc7");
	if (extra_msr_offset)
		fprintf(stderr, "        MSR 0x%x ", extra_msr_offset);

	putc('\n', stderr);
}

void dump_cnt(struct counters *cnt)
{
	fprintf(stderr, "package: %d ", cnt->pkg);
	fprintf(stderr, "core:: %d ", cnt->core);
	fprintf(stderr, "CPU: %d ", cnt->cpu);
	fprintf(stderr, "TSC: %016llX\n", cnt->tsc);
	fprintf(stderr, "c3: %016llX\n", cnt->c3);
	fprintf(stderr, "c6: %016llX\n", cnt->c6);
	fprintf(stderr, "c7: %016llX\n", cnt->c7);
	fprintf(stderr, "aperf: %016llX\n", cnt->aperf);
	fprintf(stderr, "pc2: %016llX\n", cnt->pc2);
	fprintf(stderr, "pc3: %016llX\n", cnt->pc3);
	fprintf(stderr, "pc6: %016llX\n", cnt->pc6);
	fprintf(stderr, "pc7: %016llX\n", cnt->pc7);
	fprintf(stderr, "msr0x%x: %016llX\n", extra_msr_offset, cnt->extra_msr);
}

void dump_list(struct counters *cnt)
{
	printf("dump_list 0x%p\n", cnt);

	for (; cnt; cnt = cnt->next)
		dump_cnt(cnt);
}

void print_cnt(struct counters *p)
{
	double interval_float;

	interval_float = tv_delta.tv_sec + tv_delta.tv_usec/1000000.0;

	/* topology columns, print blanks on 1st (average) line */
	if (p == cnt_average) {
		if (show_pkg)
			fprintf(stderr, " ");
		if (show_core)
			fprintf(stderr, "    ");
		if (show_cpu)
			fprintf(stderr, "    ");
	} else {
		if (show_pkg)
			fprintf(stderr, "%d", p->pkg);
		if (show_core)
			fprintf(stderr, "%4d", p->core);
		if (show_cpu)
			fprintf(stderr, "%4d", p->cpu);
	}

	/* %c0 */
	if (do_nhm_cstates) {
		if (!skip_c0)
			fprintf(stderr, "%7.2f", 100.0 * p->mperf/p->tsc);
		else
			fprintf(stderr, "   ****");
	}

	/* GHz */
	if (has_aperf) {
		if (!aperf_mperf_unstable) {
			fprintf(stderr, "%5.2f",
				1.0 * p->tsc / units * p->aperf /
				p->mperf / interval_float);
		} else {
			if (p->aperf > p->tsc || p->mperf > p->tsc) {
				fprintf(stderr, " ****");
			} else {
				fprintf(stderr, "%4.1f*",
					1.0 * p->tsc /
					units * p->aperf /
					p->mperf / interval_float);
			}
		}
	}

	/* TSC */
	fprintf(stderr, "%5.2f", 1.0 * p->tsc/units/interval_float);

	if (do_nhm_cstates) {
		if (!skip_c1)
			fprintf(stderr, "%7.2f", 100.0 * p->c1/p->tsc);
		else
			fprintf(stderr, "  ****");
	}
	if (do_nhm_cstates)
		fprintf(stderr, " %6.2f", 100.0 * p->c3/p->tsc);
	if (do_nhm_cstates)
		fprintf(stderr, " %6.2f", 100.0 * p->c6/p->tsc);
	if (do_snb_cstates)
		fprintf(stderr, " %6.2f", 100.0 * p->c7/p->tsc);
	if (do_snb_cstates)
		fprintf(stderr, " %5.2f", 100.0 * p->pc2/p->tsc);
	if (do_nhm_cstates)
		fprintf(stderr, " %5.2f", 100.0 * p->pc3/p->tsc);
	if (do_nhm_cstates)
		fprintf(stderr, " %5.2f", 100.0 * p->pc6/p->tsc);
	if (do_snb_cstates)
		fprintf(stderr, " %5.2f", 100.0 * p->pc7/p->tsc);
	if (extra_msr_offset)
		fprintf(stderr, "  0x%016llx", p->extra_msr);
	putc('\n', stderr);
}

void print_counters(struct counters *counters)
{
	struct counters *cnt;

	print_header();

	if (num_cpus > 1)
		print_cnt(cnt_average);

	for (cnt = counters; cnt != NULL; cnt = cnt->next)
		print_cnt(cnt);

}

#define SUBTRACT_COUNTER(after, before, delta) (delta = (after - before), (before > after))

int compute_delta(struct counters *after,
	struct counters *before, struct counters *delta)
{
	int errors = 0;
	int perf_err = 0;

	skip_c0 = skip_c1 = 0;

	for ( ; after && before && delta;
		after = after->next, before = before->next, delta = delta->next) {
		if (before->cpu != after->cpu) {
			printf("cpu configuration changed: %d != %d\n",
				before->cpu, after->cpu);
			return -1;
		}

		if (SUBTRACT_COUNTER(after->tsc, before->tsc, delta->tsc)) {
			fprintf(stderr, "cpu%d TSC went backwards %llX to %llX\n",
				before->cpu, before->tsc, after->tsc);
			errors++;
		}
		/* check for TSC < 1 Mcycles over interval */
		if (delta->tsc < (1000 * 1000)) {
			fprintf(stderr, "Insanely slow TSC rate,"
				" TSC stops in idle?\n");
			fprintf(stderr, "You can disable all c-states"
				" by booting with \"idle=poll\"\n");
			fprintf(stderr, "or just the deep ones with"
				" \"processor.max_cstate=1\"\n");
			exit(-3);
		}
		if (SUBTRACT_COUNTER(after->c3, before->c3, delta->c3)) {
			fprintf(stderr, "cpu%d c3 counter went backwards %llX to %llX\n",
				before->cpu, before->c3, after->c3);
			errors++;
		}
		if (SUBTRACT_COUNTER(after->c6, before->c6, delta->c6)) {
			fprintf(stderr, "cpu%d c6 counter went backwards %llX to %llX\n",
				before->cpu, before->c6, after->c6);
			errors++;
		}
		if (SUBTRACT_COUNTER(after->c7, before->c7, delta->c7)) {
			fprintf(stderr, "cpu%d c7 counter went backwards %llX to %llX\n",
				before->cpu, before->c7, after->c7);
			errors++;
		}
		if (SUBTRACT_COUNTER(after->pc2, before->pc2, delta->pc2)) {
			fprintf(stderr, "cpu%d pc2 counter went backwards %llX to %llX\n",
				before->cpu, before->pc2, after->pc2);
			errors++;
		}
		if (SUBTRACT_COUNTER(after->pc3, before->pc3, delta->pc3)) {
			fprintf(stderr, "cpu%d pc3 counter went backwards %llX to %llX\n",
				before->cpu, before->pc3, after->pc3);
			errors++;
		}
		if (SUBTRACT_COUNTER(after->pc6, before->pc6, delta->pc6)) {
			fprintf(stderr, "cpu%d pc6 counter went backwards %llX to %llX\n",
				before->cpu, before->pc6, after->pc6);
			errors++;
		}
		if (SUBTRACT_COUNTER(after->pc7, before->pc7, delta->pc7)) {
			fprintf(stderr, "cpu%d pc7 counter went backwards %llX to %llX\n",
				before->cpu, before->pc7, after->pc7);
			errors++;
		}

		perf_err = SUBTRACT_COUNTER(after->aperf, before->aperf, delta->aperf);
		if (perf_err) {
			fprintf(stderr, "cpu%d aperf counter went backwards %llX to %llX\n",
				before->cpu, before->aperf, after->aperf);
		}
		perf_err |= SUBTRACT_COUNTER(after->mperf, before->mperf, delta->mperf);
		if (perf_err) {
			fprintf(stderr, "cpu%d mperf counter went backwards %llX to %llX\n",
				before->cpu, before->mperf, after->mperf);
		}
		if (perf_err) {
			if (!aperf_mperf_unstable) {
				fprintf(stderr, "%s: APERF or MPERF went backwards *\n", progname);
				fprintf(stderr, "* Frequency results do not cover entire interval *\n");
				fprintf(stderr, "* fix this by running Linux-2.6.30 or later *\n");

				aperf_mperf_unstable = 1;
			}
			/*
			 * mperf delta is likely a huge "positive" number
			 * can not use it for calculating c0 time
			 */
			skip_c0 = 1;
			skip_c1 = 1;
		}

		/*
		 * As mperf and tsc collection are not atomic,
		 * it is possible for mperf's non-halted cycles
		 * to exceed TSC's all cycles: show c1 = 0% in that case.
		 */
		if (delta->mperf > delta->tsc)
			delta->c1 = 0;
		else /* normal case, derive c1 */
			delta->c1 = delta->tsc - delta->mperf
				- delta->c3 - delta->c6 - delta->c7;

		if (delta->mperf == 0)
			delta->mperf = 1;	/* divide by 0 protection */

		/*
		 * for "extra msr", just copy the latest w/o subtracting
		 */
		delta->extra_msr = after->extra_msr;
		if (errors) {
			fprintf(stderr, "ERROR cpu%d before:\n", before->cpu);
			dump_cnt(before);
			fprintf(stderr, "ERROR cpu%d after:\n", before->cpu);
			dump_cnt(after);
			errors = 0;
		}
	}
	return 0;
}

void compute_average(struct counters *delta, struct counters *avg)
{
	struct counters *sum;

	sum = calloc(1, sizeof(struct counters));
	if (sum == NULL) {
		perror("calloc sum");
		exit(1);
	}

	for (; delta; delta = delta->next) {
		sum->tsc += delta->tsc;
		sum->c1 += delta->c1;
		sum->c3 += delta->c3;
		sum->c6 += delta->c6;
		sum->c7 += delta->c7;
		sum->aperf += delta->aperf;
		sum->mperf += delta->mperf;
		sum->pc2 += delta->pc2;
		sum->pc3 += delta->pc3;
		sum->pc6 += delta->pc6;
		sum->pc7 += delta->pc7;
	}
	avg->tsc = sum->tsc/num_cpus;
	avg->c1 = sum->c1/num_cpus;
	avg->c3 = sum->c3/num_cpus;
	avg->c6 = sum->c6/num_cpus;
	avg->c7 = sum->c7/num_cpus;
	avg->aperf = sum->aperf/num_cpus;
	avg->mperf = sum->mperf/num_cpus;
	avg->pc2 = sum->pc2/num_cpus;
	avg->pc3 = sum->pc3/num_cpus;
	avg->pc6 = sum->pc6/num_cpus;
	avg->pc7 = sum->pc7/num_cpus;

	free(sum);
}

void get_counters(struct counters *cnt)
{
	for ( ; cnt; cnt = cnt->next) {
		cnt->tsc = get_msr(cnt->cpu, MSR_TSC);
		if (do_nhm_cstates)
			cnt->c3 = get_msr(cnt->cpu, MSR_CORE_C3_RESIDENCY);
		if (do_nhm_cstates)
			cnt->c6 = get_msr(cnt->cpu, MSR_CORE_C6_RESIDENCY);
		if (do_snb_cstates)
			cnt->c7 = get_msr(cnt->cpu, MSR_CORE_C7_RESIDENCY);
		if (has_aperf)
			cnt->aperf = get_msr(cnt->cpu, MSR_APERF);
		if (has_aperf)
			cnt->mperf = get_msr(cnt->cpu, MSR_MPERF);
		if (do_snb_cstates)
			cnt->pc2 = get_msr(cnt->cpu, MSR_PKG_C2_RESIDENCY);
		if (do_nhm_cstates)
			cnt->pc3 = get_msr(cnt->cpu, MSR_PKG_C3_RESIDENCY);
		if (do_nhm_cstates)
			cnt->pc6 = get_msr(cnt->cpu, MSR_PKG_C6_RESIDENCY);
		if (do_snb_cstates)
			cnt->pc7 = get_msr(cnt->cpu, MSR_PKG_C7_RESIDENCY);
		if (extra_msr_offset)
			cnt->extra_msr = get_msr(cnt->cpu, extra_msr_offset);
	}
}

void print_nehalem_info(void)
{
	unsigned long long msr;
	unsigned int ratio;

	if (!do_nehalem_platform_info)
		return;

	msr = get_msr(0, MSR_NEHALEM_PLATFORM_INFO);

	ratio = (msr >> 40) & 0xFF;
	fprintf(stderr, "%d * %.0f = %.0f MHz max efficiency\n",
		ratio, bclk, ratio * bclk);

	ratio = (msr >> 8) & 0xFF;
	fprintf(stderr, "%d * %.0f = %.0f MHz TSC frequency\n",
		ratio, bclk, ratio * bclk);

	if (verbose > 1)
		fprintf(stderr, "MSR_NEHALEM_PLATFORM_INFO: 0x%llx\n", msr);

	if (!do_nehalem_turbo_ratio_limit)
		return;

	msr = get_msr(0, MSR_NEHALEM_TURBO_RATIO_LIMIT);

	ratio = (msr >> 24) & 0xFF;
	if (ratio)
		fprintf(stderr, "%d * %.0f = %.0f MHz max turbo 4 active cores\n",
			ratio, bclk, ratio * bclk);

	ratio = (msr >> 16) & 0xFF;
	if (ratio)
		fprintf(stderr, "%d * %.0f = %.0f MHz max turbo 3 active cores\n",
			ratio, bclk, ratio * bclk);

	ratio = (msr >> 8) & 0xFF;
	if (ratio)
		fprintf(stderr, "%d * %.0f = %.0f MHz max turbo 2 active cores\n",
			ratio, bclk, ratio * bclk);

	ratio = (msr >> 0) & 0xFF;
	if (ratio)
		fprintf(stderr, "%d * %.0f = %.0f MHz max turbo 1 active cores\n",
			ratio, bclk, ratio * bclk);

}

void free_counter_list(struct counters *list)
{
	struct counters *p;

	for (p = list; p; ) {
		struct counters *free_me;

		free_me = p;
		p = p->next;
		free(free_me);
	}
}

void free_all_counters(void)
{
	free_counter_list(cnt_even);
	cnt_even = NULL;

	free_counter_list(cnt_odd);
	cnt_odd = NULL;

	free_counter_list(cnt_delta);
	cnt_delta = NULL;

	free_counter_list(cnt_average);
	cnt_average = NULL;
}

void insert_counters(struct counters **list,
	struct counters *new)
{
	struct counters *prev;

	/*
	 * list was empty
	 */
	if (*list == NULL) {
		new->next = *list;
		*list = new;
		return;
	}

	show_cpu = 1;	/* there is more than one CPU */

	/*
	 * insert on front of list.
	 * It is sorted by ascending package#, core#, cpu#
	 */
	if (((*list)->pkg > new->pkg) ||
	    (((*list)->pkg == new->pkg) && ((*list)->core > new->core)) ||
	    (((*list)->pkg == new->pkg) && ((*list)->core == new->core) && ((*list)->cpu > new->cpu))) {
		new->next = *list;
		*list = new;
		return;
	}

	prev = *list;

	while (prev->next && (prev->next->pkg < new->pkg)) {
		prev = prev->next;
		show_pkg = 1;	/* there is more than 1 package */
	}

	while (prev->next && (prev->next->pkg == new->pkg)
		&& (prev->next->core < new->core)) {
		prev = prev->next;
		show_core = 1;	/* there is more than 1 core */
	}

	while (prev->next && (prev->next->pkg == new->pkg)
		&& (prev->next->core == new->core)
		&& (prev->next->cpu < new->cpu)) {
		prev = prev->next;
	}

	/*
	 * insert after "prev"
	 */
	new->next = prev->next;
	prev->next = new;
}

void alloc_new_counters(int pkg, int core, int cpu)
{
	struct counters *new;

	if (verbose > 1)
		printf("pkg%d core%d, cpu%d\n", pkg, core, cpu);

	new = (struct counters *)calloc(1, sizeof(struct counters));
	if (new == NULL) {
		perror("calloc");
		exit(1);
	}
	new->pkg = pkg;
	new->core = core;
	new->cpu = cpu;
	insert_counters(&cnt_odd, new);

	new = (struct counters *)calloc(1,
		sizeof(struct counters));
	if (new == NULL) {
		perror("calloc");
		exit(1);
	}
	new->pkg = pkg;
	new->core = core;
	new->cpu = cpu;
	insert_counters(&cnt_even, new);

	new = (struct counters *)calloc(1, sizeof(struct counters));
	if (new == NULL) {
		perror("calloc");
		exit(1);
	}
	new->pkg = pkg;
	new->core = core;
	new->cpu = cpu;
	insert_counters(&cnt_delta, new);

	new = (struct counters *)calloc(1, sizeof(struct counters));
	if (new == NULL) {
		perror("calloc");
		exit(1);
	}
	new->pkg = pkg;
	new->core = core;
	new->cpu = cpu;
	cnt_average = new;
}

int get_physical_package_id(int cpu)
{
	char path[64];
	FILE *filep;
	int pkg;

	sprintf(path, "/sys/devices/system/cpu/cpu%d/topology/physical_package_id", cpu);
	filep = fopen(path, "r");
	if (filep == NULL) {
		perror(path);
		exit(1);
	}
	fscanf(filep, "%d", &pkg);
	fclose(filep);
	return pkg;
}

int get_core_id(int cpu)
{
	char path[64];
	FILE *filep;
	int core;

	sprintf(path, "/sys/devices/system/cpu/cpu%d/topology/core_id", cpu);
	filep = fopen(path, "r");
	if (filep == NULL) {
		perror(path);
		exit(1);
	}
	fscanf(filep, "%d", &core);
	fclose(filep);
	return core;
}

/*
 * run func(index, cpu) on every cpu in /proc/stat
 */

int for_all_cpus(void (func)(int, int, int))
{
	FILE *fp;
	int cpu_count;
	int retval;

	fp = fopen(proc_stat, "r");
	if (fp == NULL) {
		perror(proc_stat);
		exit(1);
	}

	retval = fscanf(fp, "cpu %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d\n");
	if (retval != 0) {
		perror("/proc/stat format");
		exit(1);
	}

	for (cpu_count = 0; ; cpu_count++) {
		int cpu;

		retval = fscanf(fp, "cpu%u %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d\n", &cpu);
		if (retval != 1)
			break;

		func(get_physical_package_id(cpu), get_core_id(cpu), cpu);
	}
	fclose(fp);
	return cpu_count;
}

void re_initialize(void)
{
	printf("turbostat: topology changed, re-initializing.\n");
	free_all_counters();
	num_cpus = for_all_cpus(alloc_new_counters);
	need_reinitialize = 0;
	printf("num_cpus is now %d\n", num_cpus);
}

void dummy(int pkg, int core, int cpu) { return; }
/*
 * check to see if a cpu came on-line
 */
void verify_num_cpus(void)
{
	int new_num_cpus;

	new_num_cpus = for_all_cpus(dummy);

	if (new_num_cpus != num_cpus) {
		if (verbose)
			printf("num_cpus was %d, is now  %d\n",
				num_cpus, new_num_cpus);
		need_reinitialize = 1;
	}
}

void turbostat_loop()
{
restart:
	get_counters(cnt_even);
	gettimeofday(&tv_even, (struct timezone *)NULL);

	while (1) {
		verify_num_cpus();
		if (need_reinitialize) {
			re_initialize();
			goto restart;
		}
		sleep(interval_sec);
		get_counters(cnt_odd);
		gettimeofday(&tv_odd, (struct timezone *)NULL);

		compute_delta(cnt_odd, cnt_even, cnt_delta);
		timersub(&tv_odd, &tv_even, &tv_delta);
		compute_average(cnt_delta, cnt_average);
		print_counters(cnt_delta);
		if (need_reinitialize) {
			re_initialize();
			goto restart;
		}
		sleep(interval_sec);
		get_counters(cnt_even);
		gettimeofday(&tv_even, (struct timezone *)NULL);
		compute_delta(cnt_even, cnt_odd, cnt_delta);
		timersub(&tv_even, &tv_odd, &tv_delta);
		compute_average(cnt_delta, cnt_average);
		print_counters(cnt_delta);
	}
}

void check_dev_msr()
{
	struct stat sb;

	if (stat("/dev/cpu/0/msr", &sb)) {
		fprintf(stderr, "no /dev/cpu/0/msr\n");
		fprintf(stderr, "Try \"# modprobe msr\"\n");
		exit(-5);
	}
}

void check_super_user()
{
	if (getuid() != 0) {
		fprintf(stderr, "must be root\n");
		exit(-6);
	}
}

int has_nehalem_turbo_ratio_limit(unsigned int family, unsigned int model)
{
	if (!genuine_intel)
		return 0;

	if (family != 6)
		return 0;

	switch (model) {
	case 0x1A:	/* Core i7, Xeon 5500 series - Bloomfield, Gainstown NHM-EP */
	case 0x1E:	/* Core i7 and i5 Processor - Clarksfield, Lynnfield, Jasper Forest */
	case 0x1F:	/* Core i7 and i5 Processor - Nehalem */
	case 0x25:	/* Westmere Client - Clarkdale, Arrandale */
	case 0x2C:	/* Westmere EP - Gulftown */
	case 0x2A:	/* SNB */
	case 0x2D:	/* SNB Xeon */
		return 1;
	case 0x2E:	/* Nehalem-EX Xeon - Beckton */
	case 0x2F:	/* Westmere-EX Xeon - Eagleton */
	default:
		return 0;
	}
}

int is_snb(unsigned int family, unsigned int model)
{
	if (!genuine_intel)
		return 0;

	switch (model) {
	case 0x2A:
	case 0x2D:
		return 1;
	}
	return 0;
}

double discover_bclk(unsigned int family, unsigned int model)
{
	if (is_snb(family, model))
		return 100.00;
	else
		return 133.33;
}

void check_cpuid()
{
	unsigned int eax, ebx, ecx, edx, max_level;
	unsigned int fms, family, model, stepping;

	eax = ebx = ecx = edx = 0;

	asm("cpuid" : "=a" (max_level), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (0));

	if (ebx == 0x756e6547 && edx == 0x49656e69 && ecx == 0x6c65746e)
		genuine_intel = 1;

	if (verbose)
		fprintf(stderr, "%.4s%.4s%.4s ",
			(char *)&ebx, (char *)&edx, (char *)&ecx);

	asm("cpuid" : "=a" (fms), "=c" (ecx), "=d" (edx) : "a" (1) : "ebx");
	family = (fms >> 8) & 0xf;
	model = (fms >> 4) & 0xf;
	stepping = fms & 0xf;
	if (family == 6 || family == 0xf)
		model += ((fms >> 16) & 0xf) << 4;

	if (verbose)
		fprintf(stderr, "%d CPUID levels; family:model:stepping 0x%x:%x:%x (%d:%d:%d)\n",
			max_level, family, model, stepping, family, model, stepping);

	if (!(edx & (1 << 5))) {
		fprintf(stderr, "CPUID: no MSR\n");
		exit(1);
	}

	/*
	 * check max extended function levels of CPUID.
	 * This is needed to check for invariant TSC.
	 * This check is valid for both Intel and AMD.
	 */
	ebx = ecx = edx = 0;
	asm("cpuid" : "=a" (max_level), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (0x80000000));

	if (max_level < 0x80000007) {
		fprintf(stderr, "CPUID: no invariant TSC (max_level 0x%x)\n", max_level);
		exit(1);
	}

	/*
	 * Non-Stop TSC is advertised by CPUID.EAX=0x80000007: EDX.bit8
	 * this check is valid for both Intel and AMD
	 */
	asm("cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (0x80000007));
	has_invariant_tsc = edx & (1 << 8);

	if (!has_invariant_tsc) {
		fprintf(stderr, "No invariant TSC\n");
		exit(1);
	}

	/*
	 * APERF/MPERF is advertised by CPUID.EAX=0x6: ECX.bit0
	 * this check is valid for both Intel and AMD
	 */

	asm("cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (0x6));
	has_aperf = ecx & (1 << 0);
	if (!has_aperf) {
		fprintf(stderr, "No APERF MSR\n");
		exit(1);
	}

	do_nehalem_platform_info = genuine_intel && has_invariant_tsc;
	do_nhm_cstates = genuine_intel;	/* all Intel w/ non-stop TSC have NHM counters */
	do_snb_cstates = is_snb(family, model);
	bclk = discover_bclk(family, model);

	do_nehalem_turbo_ratio_limit = has_nehalem_turbo_ratio_limit(family, model);
}


void usage()
{
	fprintf(stderr, "%s: [-v] [-M MSR#] [-i interval_sec | command ...]\n",
		progname);
	exit(1);
}


/*
 * in /dev/cpu/ return success for names that are numbers
 * ie. filter out ".", "..", "microcode".
 */
int dir_filter(const struct dirent *dirp)
{
	if (isdigit(dirp->d_name[0]))
		return 1;
	else
		return 0;
}

int open_dev_cpu_msr(int dummy1)
{
	return 0;
}

void turbostat_init()
{
	check_cpuid();

	check_dev_msr();
	check_super_user();

	num_cpus = for_all_cpus(alloc_new_counters);

	if (verbose)
		print_nehalem_info();
}

int fork_it(char **argv)
{
	int retval;
	pid_t child_pid;
	get_counters(cnt_even);
	gettimeofday(&tv_even, (struct timezone *)NULL);

	child_pid = fork();
	if (!child_pid) {
		/* child */
		execvp(argv[0], argv);
	} else {
		int status;

		/* parent */
		if (child_pid == -1) {
			perror("fork");
			exit(1);
		}

		signal(SIGINT, SIG_IGN);
		signal(SIGQUIT, SIG_IGN);
		if (waitpid(child_pid, &status, 0) == -1) {
			perror("wait");
			exit(1);
		}
	}
	get_counters(cnt_odd);
	gettimeofday(&tv_odd, (struct timezone *)NULL);
	retval = compute_delta(cnt_odd, cnt_even, cnt_delta);

	timersub(&tv_odd, &tv_even, &tv_delta);
	compute_average(cnt_delta, cnt_average);
	if (!retval)
		print_counters(cnt_delta);

	fprintf(stderr, "%.6f sec\n", tv_delta.tv_sec + tv_delta.tv_usec/1000000.0);

	return 0;
}

void cmdline(int argc, char **argv)
{
	int opt;

	progname = argv[0];

	while ((opt = getopt(argc, argv, "+vi:M:")) != -1) {
		switch (opt) {
		case 'v':
			verbose++;
			break;
		case 'i':
			interval_sec = atoi(optarg);
			break;
		case 'M':
			sscanf(optarg, "%x", &extra_msr_offset);
			if (verbose > 1)
				fprintf(stderr, "MSR 0x%X\n", extra_msr_offset);
			break;
		default:
			usage();
		}
	}
}

int main(int argc, char **argv)
{
	cmdline(argc, argv);

	if (verbose > 1)
		fprintf(stderr, "turbostat Dec 6, 2010"
			" - Len Brown <lenb@kernel.org>\n");
	if (verbose > 1)
		fprintf(stderr, "http://userweb.kernel.org/~lenb/acpi/utils/pmtools/turbostat/\n");

	turbostat_init();

	/*
	 * if any params left, it must be a command to fork
	 */
	if (argc - optind)
		return fork_it(argv + optind);
	else
		turbostat_loop();

	return 0;
}