#include <sys/types.h>
#include <sys/sysctl.h>

#include <stdio.h>
#include <stdint.h>
#include <unistd.h>

#define MWAIT_CX_MAX    8

struct cx_stat {
        char            sysctl_name[52];
        char            state_name[4];
};

static void     getstats(uint64_t[]);

static struct cx_stat   cx_stats[MWAIT_CX_MAX];
static int              cx_stats_cnt;

int
main(void)
{
        uint64_t count[MWAIT_CX_MAX], prev_count[MWAIT_CX_MAX];
        int i;

        for (i = 0; i < MWAIT_CX_MAX; ++i) {
                char name[64];
                size_t len;
                int subcnt;

                snprintf(name, sizeof(name), "machdep.mwait.C%d.subcnt", i);

                len = sizeof(subcnt);
                sysctlbyname(name, &subcnt, &len, NULL, 0);
                if (subcnt == 0)
                        continue;

                snprintf(cx_stats[cx_stats_cnt].state_name,
                    sizeof(cx_stats[cx_stats_cnt].state_name), "C%d", i);
                snprintf(cx_stats[cx_stats_cnt].sysctl_name,
                    sizeof(cx_stats[cx_stats_cnt].sysctl_name),
                    "machdep.mwait.C%d.entered", i);
                ++cx_stats_cnt;
        }

        getstats(prev_count);

        for (;;) {
                getstats(count);

                for (i = 0; i < cx_stats_cnt; ++i) {
                        printf("%s %-5ju ", cx_stats[i].state_name,
                            (uintmax_t)(count[i] - prev_count[i]));
                        prev_count[i] = count[i];
                }
                printf("\n");
                fflush(stdout);

                sleep(1);
        }
}

static void
getstats(uint64_t count[])
{
        int i;

        for (i = 0; i < cx_stats_cnt; ++i) {
                size_t len;

                len = sizeof(uint64_t);
                sysctlbyname(cx_stats[i].sysctl_name, &count[i], &len, NULL, 0);
        }
}