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
free_cpu_affinity(struct idle_prof_thread * ipt)46 static void free_cpu_affinity(struct idle_prof_thread *ipt)
47 {
48 #if defined(FIO_HAVE_CPU_AFFINITY)
49 fio_cpuset_exit(&ipt->cpu_mask);
50 #endif
51 }
52
set_cpu_affinity(struct idle_prof_thread * ipt)53 static int set_cpu_affinity(struct idle_prof_thread *ipt)
54 {
55 #if defined(FIO_HAVE_CPU_AFFINITY)
56 if (fio_cpuset_init(&ipt->cpu_mask)) {
57 log_err("fio: cpuset init failed\n");
58 return -1;
59 }
60
61 fio_cpu_set(&ipt->cpu_mask, ipt->cpu);
62
63 if (fio_setaffinity(gettid(), ipt->cpu_mask)) {
64 log_err("fio: fio_setaffinity failed\n");
65 fio_cpuset_exit(&ipt->cpu_mask);
66 return -1;
67 }
68
69 return 0;
70 #else
71 log_err("fio: fio_setaffinity not supported\n");
72 return -1;
73 #endif
74 }
75
idle_prof_thread_fn(void * data)76 static void *idle_prof_thread_fn(void *data)
77 {
78 int retval;
79 unsigned long j, k;
80 struct idle_prof_thread *ipt = data;
81
82 /* wait for all threads are spawned */
83 pthread_mutex_lock(&ipt->init_lock);
84
85 /* exit if any other thread failed to start */
86 if (ipc.status == IDLE_PROF_STATUS_ABORT) {
87 pthread_mutex_unlock(&ipt->init_lock);
88 return NULL;
89 }
90
91 retval = set_cpu_affinity(ipt);
92 if (retval == -1) {
93 ipt->state = TD_EXITED;
94 pthread_mutex_unlock(&ipt->init_lock);
95 return NULL;
96 }
97
98 ipt->cali_time = calibrate_unit(ipt->data);
99
100 /* delay to set IDLE class till now for better calibration accuracy */
101 #if defined(CONFIG_SCHED_IDLE)
102 if ((retval = fio_set_sched_idle()))
103 log_err("fio: fio_set_sched_idle failed\n");
104 #else
105 retval = -1;
106 log_err("fio: fio_set_sched_idle not supported\n");
107 #endif
108 if (retval == -1) {
109 ipt->state = TD_EXITED;
110 pthread_mutex_unlock(&ipt->init_lock);
111 goto do_exit;
112 }
113
114 ipt->state = TD_INITIALIZED;
115
116 /* signal the main thread that calibration is done */
117 pthread_cond_signal(&ipt->cond);
118 pthread_mutex_unlock(&ipt->init_lock);
119
120 /* wait for other calibration to finish */
121 pthread_mutex_lock(&ipt->start_lock);
122
123 /* exit if other threads failed to initialize */
124 if (ipc.status == IDLE_PROF_STATUS_ABORT) {
125 pthread_mutex_unlock(&ipt->start_lock);
126 goto do_exit;
127 }
128
129 /* exit if we are doing calibration only */
130 if (ipc.status == IDLE_PROF_STATUS_CALI_STOP) {
131 pthread_mutex_unlock(&ipt->start_lock);
132 goto do_exit;
133 }
134
135 fio_gettime(&ipt->tps, NULL);
136 ipt->state = TD_RUNNING;
137
138 j = 0;
139 while (1) {
140 for (k = 0; k < page_size; k++) {
141 ipt->data[(k + j) % page_size] = k % 256;
142 if (ipc.status == IDLE_PROF_STATUS_PROF_STOP) {
143 fio_gettime(&ipt->tpe, NULL);
144 goto idle_prof_done;
145 }
146 }
147 j++;
148 }
149
150 idle_prof_done:
151
152 ipt->loops = j + (double) k / page_size;
153 ipt->state = TD_EXITED;
154 pthread_mutex_unlock(&ipt->start_lock);
155
156 do_exit:
157 free_cpu_affinity(ipt);
158 return NULL;
159 }
160
161 /* calculate mean and standard deviation to complete an unit of work */
calibration_stats(void)162 static void calibration_stats(void)
163 {
164 int i;
165 double sum = 0.0, var = 0.0;
166 struct idle_prof_thread *ipt;
167
168 for (i = 0; i < ipc.nr_cpus; i++) {
169 ipt = &ipc.ipts[i];
170 sum += ipt->cali_time;
171 }
172
173 ipc.cali_mean = sum/ipc.nr_cpus;
174
175 for (i = 0; i < ipc.nr_cpus; i++) {
176 ipt = &ipc.ipts[i];
177 var += pow(ipt->cali_time-ipc.cali_mean, 2);
178 }
179
180 ipc.cali_stddev = sqrt(var/(ipc.nr_cpus-1));
181 }
182
fio_idle_prof_init(void)183 void fio_idle_prof_init(void)
184 {
185 int i, ret;
186 struct timeval tp;
187 struct timespec ts;
188 pthread_attr_t tattr;
189 struct idle_prof_thread *ipt;
190
191 ipc.nr_cpus = cpus_online();
192 ipc.status = IDLE_PROF_STATUS_OK;
193
194 if (ipc.opt == IDLE_PROF_OPT_NONE)
195 return;
196
197 if ((ret = pthread_attr_init(&tattr))) {
198 log_err("fio: pthread_attr_init %s\n", strerror(ret));
199 return;
200 }
201 if ((ret = pthread_attr_setscope(&tattr, PTHREAD_SCOPE_SYSTEM))) {
202 log_err("fio: pthread_attr_setscope %s\n", strerror(ret));
203 return;
204 }
205
206 ipc.ipts = malloc(ipc.nr_cpus * sizeof(struct idle_prof_thread));
207 if (!ipc.ipts) {
208 log_err("fio: malloc failed\n");
209 return;
210 }
211
212 ipc.buf = malloc(ipc.nr_cpus * page_size);
213 if (!ipc.buf) {
214 log_err("fio: malloc failed\n");
215 free(ipc.ipts);
216 return;
217 }
218
219 /*
220 * profiling aborts on any single thread failure since the
221 * result won't be accurate if any cpu is not used.
222 */
223 for (i = 0; i < ipc.nr_cpus; i++) {
224 ipt = &ipc.ipts[i];
225
226 ipt->cpu = i;
227 ipt->state = TD_NOT_CREATED;
228 ipt->data = (unsigned char *)(ipc.buf + page_size * i);
229
230 if ((ret = pthread_mutex_init(&ipt->init_lock, NULL))) {
231 ipc.status = IDLE_PROF_STATUS_ABORT;
232 log_err("fio: pthread_mutex_init %s\n", strerror(ret));
233 break;
234 }
235
236 if ((ret = pthread_mutex_init(&ipt->start_lock, NULL))) {
237 ipc.status = IDLE_PROF_STATUS_ABORT;
238 log_err("fio: pthread_mutex_init %s\n", strerror(ret));
239 break;
240 }
241
242 if ((ret = pthread_cond_init(&ipt->cond, NULL))) {
243 ipc.status = IDLE_PROF_STATUS_ABORT;
244 log_err("fio: pthread_cond_init %s\n", strerror(ret));
245 break;
246 }
247
248 /* make sure all threads are spawned before they start */
249 pthread_mutex_lock(&ipt->init_lock);
250
251 /* make sure all threads finish init before profiling starts */
252 pthread_mutex_lock(&ipt->start_lock);
253
254 if ((ret = pthread_create(&ipt->thread, &tattr, idle_prof_thread_fn, ipt))) {
255 ipc.status = IDLE_PROF_STATUS_ABORT;
256 log_err("fio: pthread_create %s\n", strerror(ret));
257 break;
258 } else
259 ipt->state = TD_CREATED;
260
261 if ((ret = pthread_detach(ipt->thread))) {
262 /* log error and let the thread spin */
263 log_err("fio: pthread_detatch %s\n", strerror(ret));
264 }
265 }
266
267 /*
268 * let good threads continue so that they can exit
269 * if errors on other threads occurred previously.
270 */
271 for (i = 0; i < ipc.nr_cpus; i++) {
272 ipt = &ipc.ipts[i];
273 pthread_mutex_unlock(&ipt->init_lock);
274 }
275
276 if (ipc.status == IDLE_PROF_STATUS_ABORT)
277 return;
278
279 /* wait for calibration to finish */
280 for (i = 0; i < ipc.nr_cpus; i++) {
281 ipt = &ipc.ipts[i];
282 pthread_mutex_lock(&ipt->init_lock);
283 while ((ipt->state != TD_EXITED) &&
284 (ipt->state!=TD_INITIALIZED)) {
285 fio_gettime(&tp, NULL);
286 ts.tv_sec = tp.tv_sec + 1;
287 ts.tv_nsec = tp.tv_usec * 1000;
288 pthread_cond_timedwait(&ipt->cond, &ipt->init_lock, &ts);
289 }
290 pthread_mutex_unlock(&ipt->init_lock);
291
292 /*
293 * any thread failed to initialize would abort other threads
294 * later after fio_idle_prof_start.
295 */
296 if (ipt->state == TD_EXITED)
297 ipc.status = IDLE_PROF_STATUS_ABORT;
298 }
299
300 if (ipc.status != IDLE_PROF_STATUS_ABORT)
301 calibration_stats();
302 else
303 ipc.cali_mean = ipc.cali_stddev = 0.0;
304
305 if (ipc.opt == IDLE_PROF_OPT_CALI)
306 ipc.status = IDLE_PROF_STATUS_CALI_STOP;
307 }
308
fio_idle_prof_start(void)309 void fio_idle_prof_start(void)
310 {
311 int i;
312 struct idle_prof_thread *ipt;
313
314 if (ipc.opt == IDLE_PROF_OPT_NONE)
315 return;
316
317 /* unlock regardless abort is set or not */
318 for (i = 0; i < ipc.nr_cpus; i++) {
319 ipt = &ipc.ipts[i];
320 pthread_mutex_unlock(&ipt->start_lock);
321 }
322 }
323
fio_idle_prof_stop(void)324 void fio_idle_prof_stop(void)
325 {
326 int i;
327 uint64_t runt;
328 struct timeval tp;
329 struct timespec ts;
330 struct idle_prof_thread *ipt;
331
332 if (ipc.opt == IDLE_PROF_OPT_NONE)
333 return;
334
335 if (ipc.opt == IDLE_PROF_OPT_CALI)
336 return;
337
338 ipc.status = IDLE_PROF_STATUS_PROF_STOP;
339
340 /* wait for all threads to exit from profiling */
341 for (i = 0; i < ipc.nr_cpus; i++) {
342 ipt = &ipc.ipts[i];
343 pthread_mutex_lock(&ipt->start_lock);
344 while ((ipt->state != TD_EXITED) &&
345 (ipt->state!=TD_NOT_CREATED)) {
346 fio_gettime(&tp, NULL);
347 ts.tv_sec = tp.tv_sec + 1;
348 ts.tv_nsec = tp.tv_usec * 1000;
349 /* timed wait in case a signal is not received */
350 pthread_cond_timedwait(&ipt->cond, &ipt->start_lock, &ts);
351 }
352 pthread_mutex_unlock(&ipt->start_lock);
353
354 /* calculate idleness */
355 if (ipc.cali_mean != 0.0) {
356 runt = utime_since(&ipt->tps, &ipt->tpe);
357 if (runt)
358 ipt->idleness = ipt->loops * ipc.cali_mean / runt;
359 else
360 ipt->idleness = 0.0;
361 } else
362 ipt->idleness = 0.0;
363 }
364
365 /*
366 * memory allocations are freed via explicit fio_idle_prof_cleanup
367 * after profiling stats are collected by apps.
368 */
369 }
370
371 /*
372 * return system idle percentage when cpu is -1;
373 * return one cpu idle percentage otherwise.
374 */
fio_idle_prof_cpu_stat(int cpu)375 static double fio_idle_prof_cpu_stat(int cpu)
376 {
377 int i, nr_cpus = ipc.nr_cpus;
378 struct idle_prof_thread *ipt;
379 double p = 0.0;
380
381 if (ipc.opt == IDLE_PROF_OPT_NONE)
382 return 0.0;
383
384 if ((cpu >= nr_cpus) || (cpu < -1)) {
385 log_err("fio: idle profiling invalid cpu index\n");
386 return 0.0;
387 }
388
389 if (cpu == -1) {
390 for (i = 0; i < nr_cpus; i++) {
391 ipt = &ipc.ipts[i];
392 p += ipt->idleness;
393 }
394 p /= nr_cpus;
395 } else {
396 ipt = &ipc.ipts[cpu];
397 p = ipt->idleness;
398 }
399
400 return p * 100.0;
401 }
402
fio_idle_prof_cleanup(void)403 static void fio_idle_prof_cleanup(void)
404 {
405 if (ipc.ipts) {
406 free(ipc.ipts);
407 ipc.ipts = NULL;
408 }
409
410 if (ipc.buf) {
411 free(ipc.buf);
412 ipc.buf = NULL;
413 }
414 }
415
fio_idle_prof_parse_opt(const char * args)416 int fio_idle_prof_parse_opt(const char *args)
417 {
418 ipc.opt = IDLE_PROF_OPT_NONE; /* default */
419
420 if (!args) {
421 log_err("fio: empty idle-prof option string\n");
422 return -1;
423 }
424
425 #if defined(FIO_HAVE_CPU_AFFINITY) && defined(CONFIG_SCHED_IDLE)
426 if (strcmp("calibrate", args) == 0) {
427 ipc.opt = IDLE_PROF_OPT_CALI;
428 fio_idle_prof_init();
429 fio_idle_prof_start();
430 fio_idle_prof_stop();
431 show_idle_prof_stats(FIO_OUTPUT_NORMAL, NULL);
432 return 1;
433 } else if (strcmp("system", args) == 0) {
434 ipc.opt = IDLE_PROF_OPT_SYSTEM;
435 return 0;
436 } else if (strcmp("percpu", args) == 0) {
437 ipc.opt = IDLE_PROF_OPT_PERCPU;
438 return 0;
439 } else {
440 log_err("fio: incorrect idle-prof option: %s\n", args);
441 return -1;
442 }
443 #else
444 log_err("fio: idle-prof not supported on this platform\n");
445 return -1;
446 #endif
447 }
448
show_idle_prof_stats(int output,struct json_object * parent)449 void show_idle_prof_stats(int output, struct json_object *parent)
450 {
451 int i, nr_cpus = ipc.nr_cpus;
452 struct json_object *tmp;
453 char s[MAX_CPU_STR_LEN];
454
455 if (output == FIO_OUTPUT_NORMAL) {
456 if (ipc.opt > IDLE_PROF_OPT_CALI)
457 log_info("\nCPU idleness:\n");
458 else if (ipc.opt == IDLE_PROF_OPT_CALI)
459 log_info("CPU idleness:\n");
460
461 if (ipc.opt >= IDLE_PROF_OPT_SYSTEM)
462 log_info(" system: %3.2f%%\n", fio_idle_prof_cpu_stat(-1));
463
464 if (ipc.opt == IDLE_PROF_OPT_PERCPU) {
465 log_info(" percpu: %3.2f%%", fio_idle_prof_cpu_stat(0));
466 for (i = 1; i < nr_cpus; i++)
467 log_info(", %3.2f%%", fio_idle_prof_cpu_stat(i));
468 log_info("\n");
469 }
470
471 if (ipc.opt >= IDLE_PROF_OPT_CALI) {
472 log_info(" unit work: mean=%3.2fus,", ipc.cali_mean);
473 log_info(" stddev=%3.2f\n", ipc.cali_stddev);
474 }
475
476 /* dynamic mem allocations can now be freed */
477 if (ipc.opt != IDLE_PROF_OPT_NONE)
478 fio_idle_prof_cleanup();
479
480 return;
481 }
482
483 if ((ipc.opt != IDLE_PROF_OPT_NONE) && (output == FIO_OUTPUT_JSON)) {
484 if (!parent)
485 return;
486
487 tmp = json_create_object();
488 if (!tmp)
489 return;
490
491 json_object_add_value_object(parent, "cpu_idleness", tmp);
492 json_object_add_value_float(tmp, "system", fio_idle_prof_cpu_stat(-1));
493
494 if (ipc.opt == IDLE_PROF_OPT_PERCPU) {
495 for (i = 0; i < nr_cpus; i++) {
496 snprintf(s, MAX_CPU_STR_LEN, "cpu-%d", i);
497 json_object_add_value_float(tmp, s, fio_idle_prof_cpu_stat(i));
498 }
499 }
500
501 json_object_add_value_float(tmp, "unit_mean", ipc.cali_mean);
502 json_object_add_value_float(tmp, "unit_stddev", ipc.cali_stddev);
503
504 fio_idle_prof_cleanup();
505 }
506 }
507