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#include <math.h>
#include "fio.h"
#include "json.h"
#include "idletime.h"
static volatile struct idle_prof_common ipc;
/*
* Get time to complete an unit work on a particular cpu.
* The minimum number in CALIBRATE_RUNS runs is returned.
*/
static double calibrate_unit(unsigned char *data)
{
unsigned long t, i, j, k;
struct timespec tps;
double tunit = 0.0;
for (i = 0; i < CALIBRATE_RUNS; i++) {
fio_gettime(&tps, NULL);
/* scale for less variance */
for (j = 0; j < CALIBRATE_SCALE; j++) {
/* unit of work */
for (k=0; k < page_size; k++) {
data[(k + j) % page_size] = k % 256;
/*
* we won't see STOP here. this is to match
* the same statement in the profiling loop.
*/
if (ipc.status == IDLE_PROF_STATUS_PROF_STOP)
return 0.0;
}
}
t = utime_since_now(&tps);
if (!t)
continue;
/* get the minimum time to complete CALIBRATE_SCALE units */
if ((i == 0) || ((double)t < tunit))
tunit = (double)t;
}
return tunit / CALIBRATE_SCALE;
}
static void free_cpu_affinity(struct idle_prof_thread *ipt)
{
#if defined(FIO_HAVE_CPU_AFFINITY)
fio_cpuset_exit(&ipt->cpu_mask);
#endif
}
static int set_cpu_affinity(struct idle_prof_thread *ipt)
{
#if defined(FIO_HAVE_CPU_AFFINITY)
if (fio_cpuset_init(&ipt->cpu_mask)) {
log_err("fio: cpuset init failed\n");
return -1;
}
fio_cpu_set(&ipt->cpu_mask, ipt->cpu);
if (fio_setaffinity(gettid(), ipt->cpu_mask)) {
log_err("fio: fio_setaffinity failed\n");
fio_cpuset_exit(&ipt->cpu_mask);
return -1;
}
return 0;
#else
log_err("fio: fio_setaffinity not supported\n");
return -1;
#endif
}
static void *idle_prof_thread_fn(void *data)
{
int retval;
unsigned long j, k;
struct idle_prof_thread *ipt = data;
/* wait for all threads are spawned */
pthread_mutex_lock(&ipt->init_lock);
/* exit if any other thread failed to start */
if (ipc.status == IDLE_PROF_STATUS_ABORT) {
pthread_mutex_unlock(&ipt->init_lock);
return NULL;
}
retval = set_cpu_affinity(ipt);
if (retval == -1) {
ipt->state = TD_EXITED;
pthread_mutex_unlock(&ipt->init_lock);
return NULL;
}
ipt->cali_time = calibrate_unit(ipt->data);
/* delay to set IDLE class till now for better calibration accuracy */
#if defined(CONFIG_SCHED_IDLE)
if ((retval = fio_set_sched_idle()))
log_err("fio: fio_set_sched_idle failed\n");
#else
retval = -1;
log_err("fio: fio_set_sched_idle not supported\n");
#endif
if (retval == -1) {
ipt->state = TD_EXITED;
pthread_mutex_unlock(&ipt->init_lock);
goto do_exit;
}
ipt->state = TD_INITIALIZED;
/* signal the main thread that calibration is done */
pthread_cond_signal(&ipt->cond);
pthread_mutex_unlock(&ipt->init_lock);
/* wait for other calibration to finish */
pthread_mutex_lock(&ipt->start_lock);
/* exit if other threads failed to initialize */
if (ipc.status == IDLE_PROF_STATUS_ABORT) {
pthread_mutex_unlock(&ipt->start_lock);
goto do_exit;
}
/* exit if we are doing calibration only */
if (ipc.status == IDLE_PROF_STATUS_CALI_STOP) {
pthread_mutex_unlock(&ipt->start_lock);
goto do_exit;
}
fio_gettime(&ipt->tps, NULL);
ipt->state = TD_RUNNING;
j = 0;
while (1) {
for (k = 0; k < page_size; k++) {
ipt->data[(k + j) % page_size] = k % 256;
if (ipc.status == IDLE_PROF_STATUS_PROF_STOP) {
fio_gettime(&ipt->tpe, NULL);
goto idle_prof_done;
}
}
j++;
}
idle_prof_done:
ipt->loops = j + (double) k / page_size;
ipt->state = TD_EXITED;
pthread_mutex_unlock(&ipt->start_lock);
do_exit:
free_cpu_affinity(ipt);
return NULL;
}
/* calculate mean and standard deviation to complete an unit of work */
static void calibration_stats(void)
{
int i;
double sum = 0.0, var = 0.0;
struct idle_prof_thread *ipt;
for (i = 0; i < ipc.nr_cpus; i++) {
ipt = &ipc.ipts[i];
sum += ipt->cali_time;
}
ipc.cali_mean = sum/ipc.nr_cpus;
for (i = 0; i < ipc.nr_cpus; i++) {
ipt = &ipc.ipts[i];
var += pow(ipt->cali_time-ipc.cali_mean, 2);
}
ipc.cali_stddev = sqrt(var/(ipc.nr_cpus-1));
}
void fio_idle_prof_init(void)
{
int i, ret;
struct timespec ts;
pthread_attr_t tattr;
pthread_condattr_t cattr;
struct idle_prof_thread *ipt;
ipc.nr_cpus = cpus_online();
ipc.status = IDLE_PROF_STATUS_OK;
if (ipc.opt == IDLE_PROF_OPT_NONE)
return;
ret = pthread_condattr_init(&cattr);
assert(ret == 0);
#ifdef CONFIG_PTHREAD_CONDATTR_SETCLOCK
ret = pthread_condattr_setclock(&cattr, CLOCK_MONOTONIC);
assert(ret == 0);
#endif
if ((ret = pthread_attr_init(&tattr))) {
log_err("fio: pthread_attr_init %s\n", strerror(ret));
return;
}
if ((ret = pthread_attr_setscope(&tattr, PTHREAD_SCOPE_SYSTEM))) {
log_err("fio: pthread_attr_setscope %s\n", strerror(ret));
return;
}
ipc.ipts = malloc(ipc.nr_cpus * sizeof(struct idle_prof_thread));
if (!ipc.ipts) {
log_err("fio: malloc failed\n");
return;
}
ipc.buf = malloc(ipc.nr_cpus * page_size);
if (!ipc.buf) {
log_err("fio: malloc failed\n");
free(ipc.ipts);
return;
}
/*
* profiling aborts on any single thread failure since the
* result won't be accurate if any cpu is not used.
*/
for (i = 0; i < ipc.nr_cpus; i++) {
ipt = &ipc.ipts[i];
ipt->cpu = i;
ipt->state = TD_NOT_CREATED;
ipt->data = (unsigned char *)(ipc.buf + page_size * i);
if ((ret = pthread_mutex_init(&ipt->init_lock, NULL))) {
ipc.status = IDLE_PROF_STATUS_ABORT;
log_err("fio: pthread_mutex_init %s\n", strerror(ret));
break;
}
if ((ret = pthread_mutex_init(&ipt->start_lock, NULL))) {
ipc.status = IDLE_PROF_STATUS_ABORT;
log_err("fio: pthread_mutex_init %s\n", strerror(ret));
break;
}
if ((ret = pthread_cond_init(&ipt->cond, &cattr))) {
ipc.status = IDLE_PROF_STATUS_ABORT;
log_err("fio: pthread_cond_init %s\n", strerror(ret));
break;
}
/* make sure all threads are spawned before they start */
pthread_mutex_lock(&ipt->init_lock);
/* make sure all threads finish init before profiling starts */
pthread_mutex_lock(&ipt->start_lock);
if ((ret = pthread_create(&ipt->thread, &tattr, idle_prof_thread_fn, ipt))) {
ipc.status = IDLE_PROF_STATUS_ABORT;
log_err("fio: pthread_create %s\n", strerror(ret));
break;
} else
ipt->state = TD_CREATED;
if ((ret = pthread_detach(ipt->thread))) {
/* log error and let the thread spin */
log_err("fio: pthread_detach %s\n", strerror(ret));
}
}
/*
* let good threads continue so that they can exit
* if errors on other threads occurred previously.
*/
for (i = 0; i < ipc.nr_cpus; i++) {
ipt = &ipc.ipts[i];
pthread_mutex_unlock(&ipt->init_lock);
}
if (ipc.status == IDLE_PROF_STATUS_ABORT)
return;
/* wait for calibration to finish */
for (i = 0; i < ipc.nr_cpus; i++) {
ipt = &ipc.ipts[i];
pthread_mutex_lock(&ipt->init_lock);
while ((ipt->state != TD_EXITED) &&
(ipt->state!=TD_INITIALIZED)) {
#ifdef CONFIG_PTHREAD_CONDATTR_SETCLOCK
clock_gettime(CLOCK_MONOTONIC, &ts);
#else
clock_gettime(CLOCK_REALTIME, &ts);
#endif
ts.tv_sec += 1;
pthread_cond_timedwait(&ipt->cond, &ipt->init_lock, &ts);
}
pthread_mutex_unlock(&ipt->init_lock);
/*
* any thread failed to initialize would abort other threads
* later after fio_idle_prof_start.
*/
if (ipt->state == TD_EXITED)
ipc.status = IDLE_PROF_STATUS_ABORT;
}
if (ipc.status != IDLE_PROF_STATUS_ABORT)
calibration_stats();
else
ipc.cali_mean = ipc.cali_stddev = 0.0;
if (ipc.opt == IDLE_PROF_OPT_CALI)
ipc.status = IDLE_PROF_STATUS_CALI_STOP;
}
void fio_idle_prof_start(void)
{
int i;
struct idle_prof_thread *ipt;
if (ipc.opt == IDLE_PROF_OPT_NONE)
return;
/* unlock regardless abort is set or not */
for (i = 0; i < ipc.nr_cpus; i++) {
ipt = &ipc.ipts[i];
pthread_mutex_unlock(&ipt->start_lock);
}
}
void fio_idle_prof_stop(void)
{
int i;
uint64_t runt;
struct timespec ts;
struct idle_prof_thread *ipt;
if (ipc.opt == IDLE_PROF_OPT_NONE)
return;
if (ipc.opt == IDLE_PROF_OPT_CALI)
return;
ipc.status = IDLE_PROF_STATUS_PROF_STOP;
/* wait for all threads to exit from profiling */
for (i = 0; i < ipc.nr_cpus; i++) {
ipt = &ipc.ipts[i];
pthread_mutex_lock(&ipt->start_lock);
while ((ipt->state != TD_EXITED) &&
(ipt->state!=TD_NOT_CREATED)) {
fio_gettime(&ts, NULL);
ts.tv_sec += 1;
/* timed wait in case a signal is not received */
pthread_cond_timedwait(&ipt->cond, &ipt->start_lock, &ts);
}
pthread_mutex_unlock(&ipt->start_lock);
/* calculate idleness */
if (ipc.cali_mean != 0.0) {
runt = utime_since(&ipt->tps, &ipt->tpe);
if (runt)
ipt->idleness = ipt->loops * ipc.cali_mean / runt;
else
ipt->idleness = 0.0;
} else
ipt->idleness = 0.0;
}
/*
* memory allocations are freed via explicit fio_idle_prof_cleanup
* after profiling stats are collected by apps.
*/
}
/*
* return system idle percentage when cpu is -1;
* return one cpu idle percentage otherwise.
*/
static double fio_idle_prof_cpu_stat(int cpu)
{
int i, nr_cpus = ipc.nr_cpus;
struct idle_prof_thread *ipt;
double p = 0.0;
if (ipc.opt == IDLE_PROF_OPT_NONE)
return 0.0;
if ((cpu >= nr_cpus) || (cpu < -1)) {
log_err("fio: idle profiling invalid cpu index\n");
return 0.0;
}
if (cpu == -1) {
for (i = 0; i < nr_cpus; i++) {
ipt = &ipc.ipts[i];
p += ipt->idleness;
}
p /= nr_cpus;
} else {
ipt = &ipc.ipts[cpu];
p = ipt->idleness;
}
return p * 100.0;
}
void fio_idle_prof_cleanup(void)
{
if (ipc.ipts) {
free(ipc.ipts);
ipc.ipts = NULL;
}
if (ipc.buf) {
free(ipc.buf);
ipc.buf = NULL;
}
}
int fio_idle_prof_parse_opt(const char *args)
{
ipc.opt = IDLE_PROF_OPT_NONE; /* default */
if (!args) {
log_err("fio: empty idle-prof option string\n");
return -1;
}
#if defined(FIO_HAVE_CPU_AFFINITY) && defined(CONFIG_SCHED_IDLE)
if (strcmp("calibrate", args) == 0) {
ipc.opt = IDLE_PROF_OPT_CALI;
fio_idle_prof_init();
fio_idle_prof_start();
fio_idle_prof_stop();
show_idle_prof_stats(FIO_OUTPUT_NORMAL, NULL, NULL);
return 1;
} else if (strcmp("system", args) == 0) {
ipc.opt = IDLE_PROF_OPT_SYSTEM;
return 0;
} else if (strcmp("percpu", args) == 0) {
ipc.opt = IDLE_PROF_OPT_PERCPU;
return 0;
} else {
log_err("fio: incorrect idle-prof option: %s\n", args);
return -1;
}
#else
log_err("fio: idle-prof not supported on this platform\n");
return -1;
#endif
}
void show_idle_prof_stats(int output, struct json_object *parent,
struct buf_output *out)
{
int i, nr_cpus = ipc.nr_cpus;
struct json_object *tmp;
char s[MAX_CPU_STR_LEN];
if (output == FIO_OUTPUT_NORMAL) {
if (ipc.opt > IDLE_PROF_OPT_CALI)
log_buf(out, "\nCPU idleness:\n");
else if (ipc.opt == IDLE_PROF_OPT_CALI)
log_buf(out, "CPU idleness:\n");
if (ipc.opt >= IDLE_PROF_OPT_SYSTEM)
log_buf(out, " system: %3.2f%%\n", fio_idle_prof_cpu_stat(-1));
if (ipc.opt == IDLE_PROF_OPT_PERCPU) {
log_buf(out, " percpu: %3.2f%%", fio_idle_prof_cpu_stat(0));
for (i = 1; i < nr_cpus; i++)
log_buf(out, ", %3.2f%%", fio_idle_prof_cpu_stat(i));
log_buf(out, "\n");
}
if (ipc.opt >= IDLE_PROF_OPT_CALI) {
log_buf(out, " unit work: mean=%3.2fus,", ipc.cali_mean);
log_buf(out, " stddev=%3.2f\n", ipc.cali_stddev);
}
return;
}
if ((ipc.opt != IDLE_PROF_OPT_NONE) && (output & FIO_OUTPUT_JSON)) {
if (!parent)
return;
tmp = json_create_object();
if (!tmp)
return;
json_object_add_value_object(parent, "cpu_idleness", tmp);
json_object_add_value_float(tmp, "system", fio_idle_prof_cpu_stat(-1));
if (ipc.opt == IDLE_PROF_OPT_PERCPU) {
for (i = 0; i < nr_cpus; i++) {
snprintf(s, MAX_CPU_STR_LEN, "cpu-%d", i);
json_object_add_value_float(tmp, s, fio_idle_prof_cpu_stat(i));
}
}
json_object_add_value_float(tmp, "unit_mean", ipc.cali_mean);
json_object_add_value_float(tmp, "unit_stddev", ipc.cali_stddev);
}
}
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