1 #include <math.h>
2 #include "json.h"
3 #include "idletime.h"
4
5 static volatile struct idle_prof_common ipc;
6
7 /*
8 * Get time to complete an unit work on a particular cpu.
9 * The minimum number in CALIBRATE_RUNS runs is returned.
10 */
calibrate_unit(unsigned char * data)11 static double calibrate_unit(unsigned char *data)
12 {
13 unsigned long t, i, j, k;
14 struct timeval tps;
15 double tunit = 0.0;
16
17 for (i = 0; i < CALIBRATE_RUNS; i++) {
18
19 fio_gettime(&tps, NULL);
20 /* scale for less variance */
21 for (j = 0; j < CALIBRATE_SCALE; j++) {
22 /* unit of work */
23 for (k=0; k < page_size; k++) {
24 data[(k + j) % page_size] = k % 256;
25 /*
26 * we won't see STOP here. this is to match
27 * the same statement in the profiling loop.
28 */
29 if (ipc.status == IDLE_PROF_STATUS_PROF_STOP)
30 return 0.0;
31 }
32 }
33
34 t = utime_since_now(&tps);
35 if (!t)
36 continue;
37
38 /* get the minimum time to complete CALIBRATE_SCALE units */
39 if ((i == 0) || ((double)t < tunit))
40 tunit = (double)t;
41 }
42
43 return tunit / CALIBRATE_SCALE;
44 }
45
set_cpu_affinity(struct idle_prof_thread * ipt)46 static int set_cpu_affinity(struct idle_prof_thread *ipt)
47 {
48 #if defined(FIO_HAVE_CPU_AFFINITY)
49 os_cpu_mask_t cpu_mask;
50
51 memset(&cpu_mask, 0, sizeof(cpu_mask));
52 fio_cpu_set(&cpu_mask, ipt->cpu);
53
54 if (fio_setaffinity(gettid(), cpu_mask)) {
55 log_err("fio: fio_setaffinity failed\n");
56 return -1;
57 }
58
59 return 0;
60 #else
61 log_err("fio: fio_setaffinity not supported\n");
62 return -1;
63 #endif
64 }
65
idle_prof_thread_fn(void * data)66 static void *idle_prof_thread_fn(void *data)
67 {
68 int retval;
69 unsigned long j, k;
70 struct idle_prof_thread *ipt = data;
71
72 /* wait for all threads are spawned */
73 pthread_mutex_lock(&ipt->init_lock);
74
75 /* exit if any other thread failed to start */
76 if (ipc.status == IDLE_PROF_STATUS_ABORT) {
77 pthread_mutex_unlock(&ipt->init_lock);
78 return NULL;
79 }
80
81 retval = set_cpu_affinity(ipt);
82 if (retval == -1) {
83 ipt->state = TD_EXITED;
84 pthread_mutex_unlock(&ipt->init_lock);
85 return NULL;
86 }
87
88 ipt->cali_time = calibrate_unit(ipt->data);
89
90 /* delay to set IDLE class till now for better calibration accuracy */
91 #if defined(CONFIG_SCHED_IDLE)
92 if ((retval = fio_set_sched_idle()))
93 log_err("fio: fio_set_sched_idle failed\n");
94 #else
95 retval = -1;
96 log_err("fio: fio_set_sched_idle not supported\n");
97 #endif
98 if (retval == -1) {
99 ipt->state = TD_EXITED;
100 pthread_mutex_unlock(&ipt->init_lock);
101 return NULL;
102 }
103
104 ipt->state = TD_INITIALIZED;
105
106 /* signal the main thread that calibration is done */
107 pthread_cond_signal(&ipt->cond);
108 pthread_mutex_unlock(&ipt->init_lock);
109
110 /* wait for other calibration to finish */
111 pthread_mutex_lock(&ipt->start_lock);
112
113 /* exit if other threads failed to initialize */
114 if (ipc.status == IDLE_PROF_STATUS_ABORT) {
115 pthread_mutex_unlock(&ipt->start_lock);
116 return NULL;
117 }
118
119 /* exit if we are doing calibration only */
120 if (ipc.status == IDLE_PROF_STATUS_CALI_STOP) {
121 pthread_mutex_unlock(&ipt->start_lock);
122 return NULL;
123 }
124
125 fio_gettime(&ipt->tps, NULL);
126 ipt->state = TD_RUNNING;
127
128 j = 0;
129 while (1) {
130 for (k = 0; k < page_size; k++) {
131 ipt->data[(k + j) % page_size] = k % 256;
132 if (ipc.status == IDLE_PROF_STATUS_PROF_STOP) {
133 fio_gettime(&ipt->tpe, NULL);
134 goto idle_prof_done;
135 }
136 }
137 j++;
138 }
139
140 idle_prof_done:
141
142 ipt->loops = j + (double) k / page_size;
143 ipt->state = TD_EXITED;
144 pthread_mutex_unlock(&ipt->start_lock);
145
146 return NULL;
147 }
148
149 /* calculate mean and standard deviation to complete an unit of work */
calibration_stats(void)150 static void calibration_stats(void)
151 {
152 int i;
153 double sum = 0.0, var = 0.0;
154 struct idle_prof_thread *ipt;
155
156 for (i = 0; i < ipc.nr_cpus; i++) {
157 ipt = &ipc.ipts[i];
158 sum += ipt->cali_time;
159 }
160
161 ipc.cali_mean = sum/ipc.nr_cpus;
162
163 for (i = 0; i < ipc.nr_cpus; i++) {
164 ipt = &ipc.ipts[i];
165 var += pow(ipt->cali_time-ipc.cali_mean, 2);
166 }
167
168 ipc.cali_stddev = sqrt(var/(ipc.nr_cpus-1));
169 }
170
fio_idle_prof_init(void)171 void fio_idle_prof_init(void)
172 {
173 int i, ret;
174 struct timeval tp;
175 struct timespec ts;
176 pthread_attr_t tattr;
177 struct idle_prof_thread *ipt;
178
179 ipc.nr_cpus = cpus_online();
180 ipc.status = IDLE_PROF_STATUS_OK;
181
182 if (ipc.opt == IDLE_PROF_OPT_NONE)
183 return;
184
185 if ((ret = pthread_attr_init(&tattr))) {
186 log_err("fio: pthread_attr_init %s\n", strerror(ret));
187 return;
188 }
189 if ((ret = pthread_attr_setscope(&tattr, PTHREAD_SCOPE_SYSTEM))) {
190 log_err("fio: pthread_attr_setscope %s\n", strerror(ret));
191 return;
192 }
193
194 ipc.ipts = malloc(ipc.nr_cpus * sizeof(struct idle_prof_thread));
195 if (!ipc.ipts) {
196 log_err("fio: malloc failed\n");
197 return;
198 }
199
200 ipc.buf = malloc(ipc.nr_cpus * page_size);
201 if (!ipc.buf) {
202 log_err("fio: malloc failed\n");
203 free(ipc.ipts);
204 return;
205 }
206
207 /*
208 * profiling aborts on any single thread failure since the
209 * result won't be accurate if any cpu is not used.
210 */
211 for (i = 0; i < ipc.nr_cpus; i++) {
212 ipt = &ipc.ipts[i];
213
214 ipt->cpu = i;
215 ipt->state = TD_NOT_CREATED;
216 ipt->data = (unsigned char *)(ipc.buf + page_size * i);
217
218 if ((ret = pthread_mutex_init(&ipt->init_lock, NULL))) {
219 ipc.status = IDLE_PROF_STATUS_ABORT;
220 log_err("fio: pthread_mutex_init %s\n", strerror(ret));
221 break;
222 }
223
224 if ((ret = pthread_mutex_init(&ipt->start_lock, NULL))) {
225 ipc.status = IDLE_PROF_STATUS_ABORT;
226 log_err("fio: pthread_mutex_init %s\n", strerror(ret));
227 break;
228 }
229
230 if ((ret = pthread_cond_init(&ipt->cond, NULL))) {
231 ipc.status = IDLE_PROF_STATUS_ABORT;
232 log_err("fio: pthread_cond_init %s\n", strerror(ret));
233 break;
234 }
235
236 /* make sure all threads are spawned before they start */
237 pthread_mutex_lock(&ipt->init_lock);
238
239 /* make sure all threads finish init before profiling starts */
240 pthread_mutex_lock(&ipt->start_lock);
241
242 if ((ret = pthread_create(&ipt->thread, &tattr, idle_prof_thread_fn, ipt))) {
243 ipc.status = IDLE_PROF_STATUS_ABORT;
244 log_err("fio: pthread_create %s\n", strerror(ret));
245 break;
246 } else
247 ipt->state = TD_CREATED;
248
249 if ((ret = pthread_detach(ipt->thread))) {
250 /* log error and let the thread spin */
251 log_err("fio: pthread_detatch %s\n", strerror(ret));
252 }
253 }
254
255 /*
256 * let good threads continue so that they can exit
257 * if errors on other threads occurred previously.
258 */
259 for (i = 0; i < ipc.nr_cpus; i++) {
260 ipt = &ipc.ipts[i];
261 pthread_mutex_unlock(&ipt->init_lock);
262 }
263
264 if (ipc.status == IDLE_PROF_STATUS_ABORT)
265 return;
266
267 /* wait for calibration to finish */
268 for (i = 0; i < ipc.nr_cpus; i++) {
269 ipt = &ipc.ipts[i];
270 pthread_mutex_lock(&ipt->init_lock);
271 while ((ipt->state != TD_EXITED) &&
272 (ipt->state!=TD_INITIALIZED)) {
273 fio_gettime(&tp, NULL);
274 ts.tv_sec = tp.tv_sec + 1;
275 ts.tv_nsec = tp.tv_usec * 1000;
276 pthread_cond_timedwait(&ipt->cond, &ipt->init_lock, &ts);
277 }
278 pthread_mutex_unlock(&ipt->init_lock);
279
280 /*
281 * any thread failed to initialize would abort other threads
282 * later after fio_idle_prof_start.
283 */
284 if (ipt->state == TD_EXITED)
285 ipc.status = IDLE_PROF_STATUS_ABORT;
286 }
287
288 if (ipc.status != IDLE_PROF_STATUS_ABORT)
289 calibration_stats();
290 else
291 ipc.cali_mean = ipc.cali_stddev = 0.0;
292
293 if (ipc.opt == IDLE_PROF_OPT_CALI)
294 ipc.status = IDLE_PROF_STATUS_CALI_STOP;
295 }
296
fio_idle_prof_start(void)297 void fio_idle_prof_start(void)
298 {
299 int i;
300 struct idle_prof_thread *ipt;
301
302 if (ipc.opt == IDLE_PROF_OPT_NONE)
303 return;
304
305 /* unlock regardless abort is set or not */
306 for (i = 0; i < ipc.nr_cpus; i++) {
307 ipt = &ipc.ipts[i];
308 pthread_mutex_unlock(&ipt->start_lock);
309 }
310 }
311
fio_idle_prof_stop(void)312 void fio_idle_prof_stop(void)
313 {
314 int i;
315 uint64_t runt;
316 struct timeval tp;
317 struct timespec ts;
318 struct idle_prof_thread *ipt;
319
320 if (ipc.opt == IDLE_PROF_OPT_NONE)
321 return;
322
323 if (ipc.opt == IDLE_PROF_OPT_CALI)
324 return;
325
326 ipc.status = IDLE_PROF_STATUS_PROF_STOP;
327
328 /* wait for all threads to exit from profiling */
329 for (i = 0; i < ipc.nr_cpus; i++) {
330 ipt = &ipc.ipts[i];
331 pthread_mutex_lock(&ipt->start_lock);
332 while ((ipt->state != TD_EXITED) &&
333 (ipt->state!=TD_NOT_CREATED)) {
334 fio_gettime(&tp, NULL);
335 ts.tv_sec = tp.tv_sec + 1;
336 ts.tv_nsec = tp.tv_usec * 1000;
337 /* timed wait in case a signal is not received */
338 pthread_cond_timedwait(&ipt->cond, &ipt->start_lock, &ts);
339 }
340 pthread_mutex_unlock(&ipt->start_lock);
341
342 /* calculate idleness */
343 if (ipc.cali_mean != 0.0) {
344 runt = utime_since(&ipt->tps, &ipt->tpe);
345 if (runt)
346 ipt->idleness = ipt->loops * ipc.cali_mean / runt;
347 else
348 ipt->idleness = 0.0;
349 } else
350 ipt->idleness = 0.0;
351 }
352
353 /*
354 * memory allocations are freed via explicit fio_idle_prof_cleanup
355 * after profiling stats are collected by apps.
356 */
357 }
358
359 /*
360 * return system idle percentage when cpu is -1;
361 * return one cpu idle percentage otherwise.
362 */
fio_idle_prof_cpu_stat(int cpu)363 static double fio_idle_prof_cpu_stat(int cpu)
364 {
365 int i, nr_cpus = ipc.nr_cpus;
366 struct idle_prof_thread *ipt;
367 double p = 0.0;
368
369 if (ipc.opt == IDLE_PROF_OPT_NONE)
370 return 0.0;
371
372 if ((cpu >= nr_cpus) || (cpu < -1)) {
373 log_err("fio: idle profiling invalid cpu index\n");
374 return 0.0;
375 }
376
377 if (cpu == -1) {
378 for (i = 0; i < nr_cpus; i++) {
379 ipt = &ipc.ipts[i];
380 p += ipt->idleness;
381 }
382 p /= nr_cpus;
383 } else {
384 ipt = &ipc.ipts[cpu];
385 p = ipt->idleness;
386 }
387
388 return p * 100.0;
389 }
390
fio_idle_prof_cleanup(void)391 static void fio_idle_prof_cleanup(void)
392 {
393 if (ipc.ipts) {
394 free(ipc.ipts);
395 ipc.ipts = NULL;
396 }
397
398 if (ipc.buf) {
399 free(ipc.buf);
400 ipc.buf = NULL;
401 }
402 }
403
fio_idle_prof_parse_opt(const char * args)404 int fio_idle_prof_parse_opt(const char *args)
405 {
406 ipc.opt = IDLE_PROF_OPT_NONE; /* default */
407
408 if (!args) {
409 log_err("fio: empty idle-prof option string\n");
410 return -1;
411 }
412
413 #if defined(FIO_HAVE_CPU_AFFINITY) && defined(CONFIG_SCHED_IDLE)
414 if (strcmp("calibrate", args) == 0) {
415 ipc.opt = IDLE_PROF_OPT_CALI;
416 fio_idle_prof_init();
417 fio_idle_prof_start();
418 fio_idle_prof_stop();
419 show_idle_prof_stats(FIO_OUTPUT_NORMAL, NULL);
420 return 1;
421 } else if (strcmp("system", args) == 0) {
422 ipc.opt = IDLE_PROF_OPT_SYSTEM;
423 return 0;
424 } else if (strcmp("percpu", args) == 0) {
425 ipc.opt = IDLE_PROF_OPT_PERCPU;
426 return 0;
427 } else {
428 log_err("fio: incorrect idle-prof option: %s\n", args);
429 return -1;
430 }
431 #else
432 log_err("fio: idle-prof not supported on this platform\n");
433 return -1;
434 #endif
435 }
436
show_idle_prof_stats(int output,struct json_object * parent)437 void show_idle_prof_stats(int output, struct json_object *parent)
438 {
439 int i, nr_cpus = ipc.nr_cpus;
440 struct json_object *tmp;
441 char s[MAX_CPU_STR_LEN];
442
443 if (output == FIO_OUTPUT_NORMAL) {
444 if (ipc.opt > IDLE_PROF_OPT_CALI)
445 log_info("\nCPU idleness:\n");
446 else if (ipc.opt == IDLE_PROF_OPT_CALI)
447 log_info("CPU idleness:\n");
448
449 if (ipc.opt >= IDLE_PROF_OPT_SYSTEM)
450 log_info(" system: %3.2f%%\n", fio_idle_prof_cpu_stat(-1));
451
452 if (ipc.opt == IDLE_PROF_OPT_PERCPU) {
453 log_info(" percpu: %3.2f%%", fio_idle_prof_cpu_stat(0));
454 for (i = 1; i < nr_cpus; i++)
455 log_info(", %3.2f%%", fio_idle_prof_cpu_stat(i));
456 log_info("\n");
457 }
458
459 if (ipc.opt >= IDLE_PROF_OPT_CALI) {
460 log_info(" unit work: mean=%3.2fus,", ipc.cali_mean);
461 log_info(" stddev=%3.2f\n", ipc.cali_stddev);
462 }
463
464 /* dynamic mem allocations can now be freed */
465 if (ipc.opt != IDLE_PROF_OPT_NONE)
466 fio_idle_prof_cleanup();
467
468 return;
469 }
470
471 if ((ipc.opt != IDLE_PROF_OPT_NONE) && (output == FIO_OUTPUT_JSON)) {
472 if (!parent)
473 return;
474
475 tmp = json_create_object();
476 if (!tmp)
477 return;
478
479 json_object_add_value_object(parent, "cpu_idleness", tmp);
480 json_object_add_value_float(tmp, "system", fio_idle_prof_cpu_stat(-1));
481
482 if (ipc.opt == IDLE_PROF_OPT_PERCPU) {
483 for (i = 0; i < nr_cpus; i++) {
484 snprintf(s, MAX_CPU_STR_LEN, "cpu-%d", i);
485 json_object_add_value_float(tmp, s, fio_idle_prof_cpu_stat(i));
486 }
487 }
488
489 json_object_add_value_float(tmp, "unit_mean", ipc.cali_mean);
490 json_object_add_value_float(tmp, "unit_stddev", ipc.cali_stddev);
491
492 fio_idle_prof_cleanup();
493 }
494 }
495