6 static volatile struct idle_prof_common ipc;
9 * Get time to complete an unit work on a particular cpu.
10 * The minimum number in CALIBRATE_RUNS runs is returned.
12 static double calibrate_unit(unsigned char *data)
14 unsigned long t, i, j, k;
18 for (i = 0; i < CALIBRATE_RUNS; i++) {
20 fio_gettime(&tps, NULL);
21 /* scale for less variance */
22 for (j = 0; j < CALIBRATE_SCALE; j++) {
24 for (k=0; k < page_size; k++) {
25 data[(k + j) % page_size] = k % 256;
27 * we won't see STOP here. this is to match
28 * the same statement in the profiling loop.
30 if (ipc.status == IDLE_PROF_STATUS_PROF_STOP)
35 t = utime_since_now(&tps);
39 /* get the minimum time to complete CALIBRATE_SCALE units */
40 if ((i == 0) || ((double)t < tunit))
44 return tunit / CALIBRATE_SCALE;
47 static void free_cpu_affinity(struct idle_prof_thread *ipt)
49 #if defined(FIO_HAVE_CPU_AFFINITY)
50 fio_cpuset_exit(&ipt->cpu_mask);
54 static int set_cpu_affinity(struct idle_prof_thread *ipt)
56 #if defined(FIO_HAVE_CPU_AFFINITY)
57 if (fio_cpuset_init(&ipt->cpu_mask)) {
58 log_err("fio: cpuset init failed\n");
62 fio_cpu_set(&ipt->cpu_mask, ipt->cpu);
64 if (fio_setaffinity(gettid(), ipt->cpu_mask)) {
65 log_err("fio: fio_setaffinity failed\n");
66 fio_cpuset_exit(&ipt->cpu_mask);
72 log_err("fio: fio_setaffinity not supported\n");
77 static void *idle_prof_thread_fn(void *data)
81 struct idle_prof_thread *ipt = data;
83 /* wait for all threads are spawned */
84 pthread_mutex_lock(&ipt->init_lock);
86 /* exit if any other thread failed to start */
87 if (ipc.status == IDLE_PROF_STATUS_ABORT) {
88 pthread_mutex_unlock(&ipt->init_lock);
92 retval = set_cpu_affinity(ipt);
94 ipt->state = TD_EXITED;
95 pthread_mutex_unlock(&ipt->init_lock);
99 ipt->cali_time = calibrate_unit(ipt->data);
101 /* delay to set IDLE class till now for better calibration accuracy */
102 #if defined(CONFIG_SCHED_IDLE)
103 if ((retval = fio_set_sched_idle()))
104 log_err("fio: fio_set_sched_idle failed\n");
107 log_err("fio: fio_set_sched_idle not supported\n");
110 ipt->state = TD_EXITED;
111 pthread_mutex_unlock(&ipt->init_lock);
115 ipt->state = TD_INITIALIZED;
117 /* signal the main thread that calibration is done */
118 pthread_cond_signal(&ipt->cond);
119 pthread_mutex_unlock(&ipt->init_lock);
121 /* wait for other calibration to finish */
122 pthread_mutex_lock(&ipt->start_lock);
124 /* exit if other threads failed to initialize */
125 if (ipc.status == IDLE_PROF_STATUS_ABORT) {
126 pthread_mutex_unlock(&ipt->start_lock);
130 /* exit if we are doing calibration only */
131 if (ipc.status == IDLE_PROF_STATUS_CALI_STOP) {
132 pthread_mutex_unlock(&ipt->start_lock);
136 fio_gettime(&ipt->tps, NULL);
137 ipt->state = TD_RUNNING;
141 for (k = 0; k < page_size; k++) {
142 ipt->data[(k + j) % page_size] = k % 256;
143 if (ipc.status == IDLE_PROF_STATUS_PROF_STOP) {
144 fio_gettime(&ipt->tpe, NULL);
153 ipt->loops = j + (double) k / page_size;
154 ipt->state = TD_EXITED;
155 pthread_mutex_unlock(&ipt->start_lock);
158 free_cpu_affinity(ipt);
162 /* calculate mean and standard deviation to complete an unit of work */
163 static void calibration_stats(void)
166 double sum = 0.0, var = 0.0;
167 struct idle_prof_thread *ipt;
169 for (i = 0; i < ipc.nr_cpus; i++) {
171 sum += ipt->cali_time;
174 ipc.cali_mean = sum/ipc.nr_cpus;
176 for (i = 0; i < ipc.nr_cpus; i++) {
178 var += pow(ipt->cali_time-ipc.cali_mean, 2);
181 ipc.cali_stddev = sqrt(var/(ipc.nr_cpus-1));
184 void fio_idle_prof_init(void)
188 pthread_attr_t tattr;
189 pthread_condattr_t cattr;
190 struct idle_prof_thread *ipt;
192 ipc.nr_cpus = cpus_online();
193 ipc.status = IDLE_PROF_STATUS_OK;
195 if (ipc.opt == IDLE_PROF_OPT_NONE)
198 ret = pthread_condattr_init(&cattr);
200 #ifdef CONFIG_PTHREAD_CONDATTR_SETCLOCK
201 ret = pthread_condattr_setclock(&cattr, CLOCK_MONOTONIC);
205 if ((ret = pthread_attr_init(&tattr))) {
206 log_err("fio: pthread_attr_init %s\n", strerror(ret));
209 if ((ret = pthread_attr_setscope(&tattr, PTHREAD_SCOPE_SYSTEM))) {
210 log_err("fio: pthread_attr_setscope %s\n", strerror(ret));
214 ipc.ipts = malloc(ipc.nr_cpus * sizeof(struct idle_prof_thread));
216 log_err("fio: malloc failed\n");
220 ipc.buf = malloc(ipc.nr_cpus * page_size);
222 log_err("fio: malloc failed\n");
228 * profiling aborts on any single thread failure since the
229 * result won't be accurate if any cpu is not used.
231 for (i = 0; i < ipc.nr_cpus; i++) {
235 ipt->state = TD_NOT_CREATED;
236 ipt->data = (unsigned char *)(ipc.buf + page_size * i);
238 if ((ret = pthread_mutex_init(&ipt->init_lock, NULL))) {
239 ipc.status = IDLE_PROF_STATUS_ABORT;
240 log_err("fio: pthread_mutex_init %s\n", strerror(ret));
244 if ((ret = pthread_mutex_init(&ipt->start_lock, NULL))) {
245 ipc.status = IDLE_PROF_STATUS_ABORT;
246 log_err("fio: pthread_mutex_init %s\n", strerror(ret));
250 if ((ret = pthread_cond_init(&ipt->cond, &cattr))) {
251 ipc.status = IDLE_PROF_STATUS_ABORT;
252 log_err("fio: pthread_cond_init %s\n", strerror(ret));
256 /* make sure all threads are spawned before they start */
257 pthread_mutex_lock(&ipt->init_lock);
259 /* make sure all threads finish init before profiling starts */
260 pthread_mutex_lock(&ipt->start_lock);
262 if ((ret = pthread_create(&ipt->thread, &tattr, idle_prof_thread_fn, ipt))) {
263 ipc.status = IDLE_PROF_STATUS_ABORT;
264 log_err("fio: pthread_create %s\n", strerror(ret));
267 ipt->state = TD_CREATED;
269 if ((ret = pthread_detach(ipt->thread))) {
270 /* log error and let the thread spin */
271 log_err("fio: pthread_detach %s\n", strerror(ret));
276 * let good threads continue so that they can exit
277 * if errors on other threads occurred previously.
279 for (i = 0; i < ipc.nr_cpus; i++) {
281 pthread_mutex_unlock(&ipt->init_lock);
284 if (ipc.status == IDLE_PROF_STATUS_ABORT)
287 /* wait for calibration to finish */
288 for (i = 0; i < ipc.nr_cpus; i++) {
290 pthread_mutex_lock(&ipt->init_lock);
291 while ((ipt->state != TD_EXITED) &&
292 (ipt->state!=TD_INITIALIZED)) {
293 #ifdef CONFIG_PTHREAD_CONDATTR_SETCLOCK
294 clock_gettime(CLOCK_MONOTONIC, &ts);
296 clock_gettime(CLOCK_REALTIME, &ts);
299 pthread_cond_timedwait(&ipt->cond, &ipt->init_lock, &ts);
301 pthread_mutex_unlock(&ipt->init_lock);
304 * any thread failed to initialize would abort other threads
305 * later after fio_idle_prof_start.
307 if (ipt->state == TD_EXITED)
308 ipc.status = IDLE_PROF_STATUS_ABORT;
311 if (ipc.status != IDLE_PROF_STATUS_ABORT)
314 ipc.cali_mean = ipc.cali_stddev = 0.0;
316 if (ipc.opt == IDLE_PROF_OPT_CALI)
317 ipc.status = IDLE_PROF_STATUS_CALI_STOP;
320 void fio_idle_prof_start(void)
323 struct idle_prof_thread *ipt;
325 if (ipc.opt == IDLE_PROF_OPT_NONE)
328 /* unlock regardless abort is set or not */
329 for (i = 0; i < ipc.nr_cpus; i++) {
331 pthread_mutex_unlock(&ipt->start_lock);
335 void fio_idle_prof_stop(void)
340 struct idle_prof_thread *ipt;
342 if (ipc.opt == IDLE_PROF_OPT_NONE)
345 if (ipc.opt == IDLE_PROF_OPT_CALI)
348 ipc.status = IDLE_PROF_STATUS_PROF_STOP;
350 /* wait for all threads to exit from profiling */
351 for (i = 0; i < ipc.nr_cpus; i++) {
353 pthread_mutex_lock(&ipt->start_lock);
354 while ((ipt->state != TD_EXITED) &&
355 (ipt->state!=TD_NOT_CREATED)) {
356 fio_gettime(&ts, NULL);
358 /* timed wait in case a signal is not received */
359 pthread_cond_timedwait(&ipt->cond, &ipt->start_lock, &ts);
361 pthread_mutex_unlock(&ipt->start_lock);
363 /* calculate idleness */
364 if (ipc.cali_mean != 0.0) {
365 runt = utime_since(&ipt->tps, &ipt->tpe);
367 ipt->idleness = ipt->loops * ipc.cali_mean / runt;
375 * memory allocations are freed via explicit fio_idle_prof_cleanup
376 * after profiling stats are collected by apps.
381 * return system idle percentage when cpu is -1;
382 * return one cpu idle percentage otherwise.
384 static double fio_idle_prof_cpu_stat(int cpu)
386 int i, nr_cpus = ipc.nr_cpus;
387 struct idle_prof_thread *ipt;
390 if (ipc.opt == IDLE_PROF_OPT_NONE)
393 if ((cpu >= nr_cpus) || (cpu < -1)) {
394 log_err("fio: idle profiling invalid cpu index\n");
399 for (i = 0; i < nr_cpus; i++) {
405 ipt = &ipc.ipts[cpu];
412 void fio_idle_prof_cleanup(void)
425 int fio_idle_prof_parse_opt(const char *args)
427 ipc.opt = IDLE_PROF_OPT_NONE; /* default */
430 log_err("fio: empty idle-prof option string\n");
434 #if defined(FIO_HAVE_CPU_AFFINITY) && defined(CONFIG_SCHED_IDLE)
435 if (strcmp("calibrate", args) == 0) {
436 ipc.opt = IDLE_PROF_OPT_CALI;
437 fio_idle_prof_init();
438 fio_idle_prof_start();
439 fio_idle_prof_stop();
440 show_idle_prof_stats(FIO_OUTPUT_NORMAL, NULL, NULL);
442 } else if (strcmp("system", args) == 0) {
443 ipc.opt = IDLE_PROF_OPT_SYSTEM;
445 } else if (strcmp("percpu", args) == 0) {
446 ipc.opt = IDLE_PROF_OPT_PERCPU;
449 log_err("fio: incorrect idle-prof option: %s\n", args);
453 log_err("fio: idle-prof not supported on this platform\n");
458 void show_idle_prof_stats(int output, struct json_object *parent,
459 struct buf_output *out)
461 int i, nr_cpus = ipc.nr_cpus;
462 struct json_object *tmp;
463 char s[MAX_CPU_STR_LEN];
465 if (output == FIO_OUTPUT_NORMAL) {
466 if (ipc.opt > IDLE_PROF_OPT_CALI)
467 log_buf(out, "\nCPU idleness:\n");
468 else if (ipc.opt == IDLE_PROF_OPT_CALI)
469 log_buf(out, "CPU idleness:\n");
471 if (ipc.opt >= IDLE_PROF_OPT_SYSTEM)
472 log_buf(out, " system: %3.2f%%\n", fio_idle_prof_cpu_stat(-1));
474 if (ipc.opt == IDLE_PROF_OPT_PERCPU) {
475 log_buf(out, " percpu: %3.2f%%", fio_idle_prof_cpu_stat(0));
476 for (i = 1; i < nr_cpus; i++)
477 log_buf(out, ", %3.2f%%", fio_idle_prof_cpu_stat(i));
481 if (ipc.opt >= IDLE_PROF_OPT_CALI) {
482 log_buf(out, " unit work: mean=%3.2fus,", ipc.cali_mean);
483 log_buf(out, " stddev=%3.2f\n", ipc.cali_stddev);
489 if ((ipc.opt != IDLE_PROF_OPT_NONE) && (output & FIO_OUTPUT_JSON)) {
493 tmp = json_create_object();
497 json_object_add_value_object(parent, "cpu_idleness", tmp);
498 json_object_add_value_float(tmp, "system", fio_idle_prof_cpu_stat(-1));
500 if (ipc.opt == IDLE_PROF_OPT_PERCPU) {
501 for (i = 0; i < nr_cpus; i++) {
502 snprintf(s, MAX_CPU_STR_LEN, "cpu-%d", i);
503 json_object_add_value_float(tmp, s, fio_idle_prof_cpu_stat(i));
507 json_object_add_value_float(tmp, "unit_mean", ipc.cali_mean);
508 json_object_add_value_float(tmp, "unit_stddev", ipc.cali_stddev);