Cyril Hrubis | c459654 | 2017-06-20 15:42:18 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2017 Cyril Hrubis <chrubis@suse.cz> |
| 3 | * |
| 4 | * This program is free software: you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation, either version 2 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 16 | */ |
| 17 | |
| 18 | #include <sys/prctl.h> |
| 19 | #include <stdlib.h> |
| 20 | #include <stdio.h> |
| 21 | #include <limits.h> |
| 22 | |
| 23 | #define TST_NO_DEFAULT_MAIN |
| 24 | #include "tst_test.h" |
Cyril Hrubis | ab6b5f5 | 2017-07-20 13:27:29 +0200 | [diff] [blame] | 25 | #include "tst_clocks.h" |
Cyril Hrubis | c459654 | 2017-06-20 15:42:18 +0200 | [diff] [blame] | 26 | #include "tst_timer_test.h" |
| 27 | |
| 28 | #define MAX_SAMPLES 500 |
| 29 | |
| 30 | static const char *scall; |
| 31 | static void (*setup)(void); |
| 32 | static void (*cleanup)(void); |
| 33 | static int (*sample)(int clk_id, long long usec); |
| 34 | static struct tst_test *test; |
| 35 | |
| 36 | static long long *samples; |
| 37 | static unsigned int cur_sample; |
| 38 | static unsigned int monotonic_resolution; |
| 39 | static unsigned int timerslack; |
| 40 | |
| 41 | static char *print_frequency_plot; |
| 42 | static char *file_name; |
| 43 | static char *str_sleep_time; |
| 44 | static char *str_sample_cnt; |
| 45 | static int sleep_time = -1; |
| 46 | static int sample_cnt; |
| 47 | |
| 48 | static void print_line(char c, int len) |
| 49 | { |
| 50 | while (len-- > 0) |
| 51 | fputc(c, stderr); |
| 52 | } |
| 53 | |
| 54 | static unsigned int ceilu(float f) |
| 55 | { |
| 56 | if (f - (int)f > 0) |
| 57 | return (unsigned int)f + 1; |
| 58 | |
| 59 | return (unsigned int)f; |
| 60 | } |
| 61 | |
| 62 | static unsigned int flooru(float f) |
| 63 | { |
| 64 | return (unsigned int)f; |
| 65 | } |
| 66 | |
| 67 | static float bucket_len(unsigned int bucket, unsigned int max_bucket, |
| 68 | unsigned int cols) |
| 69 | { |
| 70 | return 1.00 * bucket * cols / max_bucket; |
| 71 | } |
| 72 | |
| 73 | static const char *table_heading = " Time: us "; |
| 74 | |
| 75 | /* |
| 76 | * Line Header: '10023 | ' |
| 77 | */ |
| 78 | static unsigned int header_len(long long max_sample) |
| 79 | { |
| 80 | unsigned int l = 1; |
| 81 | |
| 82 | while (max_sample/=10) |
| 83 | l++; |
| 84 | |
| 85 | return MAX(strlen(table_heading) + 2, l + 3); |
| 86 | } |
| 87 | |
| 88 | static void frequency_plot(void) |
| 89 | { |
| 90 | unsigned int cols = 80; |
| 91 | unsigned int rows = 20; |
| 92 | unsigned int i, buckets[rows]; |
| 93 | long long max_sample = samples[0]; |
| 94 | long long min_sample = samples[cur_sample-1]; |
| 95 | unsigned int line_header_len = header_len(max_sample); |
| 96 | unsigned int plot_line_len = cols - line_header_len; |
| 97 | unsigned int bucket_size; |
| 98 | |
| 99 | memset(buckets, 0, sizeof(buckets)); |
| 100 | |
| 101 | /* |
| 102 | * We work with discrete data buckets smaller than 1 does not make |
| 103 | * sense as well as it's a good idea to keep buckets integer sized |
| 104 | * to avoid scaling artifacts. |
| 105 | */ |
| 106 | bucket_size = MAX(1u, ceilu(1.00 * (max_sample - min_sample)/(rows-1))); |
| 107 | |
| 108 | for (i = 0; i < cur_sample; i++) { |
| 109 | unsigned int bucket; |
| 110 | bucket = flooru(1.00 * (samples[i] - min_sample)/bucket_size); |
| 111 | buckets[bucket]++; |
| 112 | } |
| 113 | |
| 114 | unsigned int max_bucket = buckets[0]; |
| 115 | for (i = 1; i < rows; i++) |
| 116 | max_bucket = MAX(max_bucket, buckets[i]); |
| 117 | |
| 118 | fprintf(stderr, "\n%*s| Frequency\n", line_header_len - 2, table_heading); |
| 119 | |
| 120 | print_line('-', cols); |
| 121 | fputc('\n', stderr); |
| 122 | |
| 123 | unsigned int l, r; |
| 124 | |
| 125 | for (l = 0; l < rows; l++) { |
| 126 | if (buckets[l]) |
| 127 | break; |
| 128 | } |
| 129 | |
| 130 | for (r = rows-1; r > l; r--) { |
| 131 | if (buckets[r]) |
| 132 | break; |
| 133 | } |
| 134 | |
| 135 | for (i = l; i <= r; i++) { |
| 136 | float len = bucket_len(buckets[i], max_bucket, plot_line_len); |
| 137 | |
| 138 | fprintf(stderr, "%*lli | ", |
| 139 | line_header_len - 3, min_sample + bucket_size*i); |
| 140 | print_line('*', len); |
| 141 | |
| 142 | if ((len - (int)len) >= 0.5) |
| 143 | fputc('+', stderr); |
| 144 | else if ((len - (int)len) >= 0.25) |
| 145 | fputc('-', stderr); |
| 146 | else if (len < 0.25 && buckets[i]) |
| 147 | fputc('.', stderr); |
| 148 | |
| 149 | fputc('\n', stderr); |
| 150 | } |
| 151 | |
| 152 | print_line('-', cols); |
| 153 | fputc('\n', stderr); |
| 154 | |
| 155 | float scale = 1.00 * plot_line_len / max_bucket; |
| 156 | |
| 157 | fprintf(stderr, |
| 158 | "%*uus | 1 sample = %.5f '*', %.5f '+', %.5f '-', non-zero '.'\n", |
| 159 | line_header_len - 5, bucket_size, scale, scale * 2, scale * 4); |
| 160 | |
| 161 | fputc('\n', stderr); |
| 162 | } |
| 163 | |
| 164 | void tst_timer_sample(void) |
| 165 | { |
| 166 | samples[cur_sample++] = tst_timer_elapsed_us(); |
| 167 | } |
| 168 | |
| 169 | static int cmp(const void *a, const void *b) |
| 170 | { |
| 171 | const long long *aa = a, *bb = b; |
| 172 | |
| 173 | return *aa < *bb; |
| 174 | } |
| 175 | |
| 176 | /* |
| 177 | * The threshold per one syscall is computed as a sum of: |
| 178 | * |
| 179 | * 400 us - accomodates for context switches, process |
| 180 | * migrations between CPUs on SMP, etc. |
| 181 | * 2*monotonic_resolution - accomodates for granurality of the CLOCK_MONOTONIC |
| 182 | * slack_per_scall - max of 0.1% of the sleep capped on 100ms or |
| 183 | * current->timer_slack_ns, which is slack allowed |
| 184 | * in kernel |
| 185 | * |
| 186 | * The formula for slack_per_scall applies to select() and *poll*() syscalls, |
| 187 | * the futex and *nanosleep() use only the timer_slack_ns, so we are a bit |
| 188 | * less strict here that we could be for these two for longer sleep times... |
| 189 | * |
| 190 | * We also allow for outliners, i.e. add some number to the threshold in case |
| 191 | * that the number of iteration is small. For large enoung number of iterations |
| 192 | * outliners are discarded and averaged out. |
| 193 | */ |
| 194 | static long long compute_threshold(long long requested_us, |
| 195 | unsigned int nsamples) |
| 196 | { |
| 197 | unsigned int slack_per_scall = MIN(100000, requested_us / 1000); |
| 198 | |
| 199 | slack_per_scall = MAX(slack_per_scall, timerslack); |
| 200 | |
| 201 | return (400 + 2 * monotonic_resolution + slack_per_scall) * nsamples |
| 202 | + 3000/nsamples; |
| 203 | } |
| 204 | |
| 205 | /* |
| 206 | * Returns number of samples to discard. |
| 207 | * |
| 208 | * We set it to either at least 1 if number of samples > 1 or 5%. |
| 209 | */ |
| 210 | static unsigned int compute_discard(unsigned int nsamples) |
| 211 | { |
| 212 | if (nsamples == 1) |
| 213 | return 0; |
| 214 | |
| 215 | return MAX(1u, nsamples / 20); |
| 216 | } |
| 217 | |
| 218 | static void write_to_file(void) |
| 219 | { |
| 220 | unsigned int i; |
| 221 | FILE *f; |
| 222 | |
| 223 | if (!file_name) |
| 224 | return; |
| 225 | |
| 226 | f = fopen(file_name, "w"); |
| 227 | |
| 228 | if (!f) { |
| 229 | tst_res(TWARN | TERRNO, |
| 230 | "Failed to open '%s'", file_name); |
| 231 | return; |
| 232 | } |
| 233 | |
| 234 | for (i = 0; i < cur_sample; i++) |
| 235 | fprintf(f, "%lli\n", samples[i]); |
| 236 | |
| 237 | if (fclose(f)) { |
| 238 | tst_res(TWARN | TERRNO, |
| 239 | "Failed to close file '%s'", file_name); |
| 240 | } |
| 241 | } |
| 242 | |
| 243 | |
| 244 | /* |
| 245 | * Timer testing function. |
| 246 | * |
| 247 | * What we do here is: |
| 248 | * |
| 249 | * * Take nsamples measurements of the timer function, the function |
| 250 | * to be sampled is defined in the the actual test. |
| 251 | * |
| 252 | * * We sort the array of samples, then: |
| 253 | * |
| 254 | * - look for outliners which are samples where the sleep time has exceeded |
| 255 | * requested sleep time by an order of magnitude and, at the same time, are |
| 256 | * greater than clock resolution multiplied by three. |
| 257 | * |
| 258 | * - check for samples where the call has woken up too early which is a plain |
| 259 | * old bug |
| 260 | * |
| 261 | * - then we compute truncated mean and compare that with the requested sleep |
| 262 | * time increased by a threshold |
| 263 | */ |
| 264 | void do_timer_test(long long usec, unsigned int nsamples) |
| 265 | { |
| 266 | long long trunc_mean, median; |
| 267 | unsigned int discard = compute_discard(nsamples); |
| 268 | unsigned int keep_samples = nsamples - discard; |
| 269 | long long threshold = compute_threshold(usec, keep_samples); |
Xiao Yang | 825459d | 2017-07-20 17:38:34 +0800 | [diff] [blame] | 270 | int i; |
Cyril Hrubis | c459654 | 2017-06-20 15:42:18 +0200 | [diff] [blame] | 271 | int failed = 0; |
| 272 | |
| 273 | tst_res(TINFO, |
| 274 | "%s sleeping for %llius %u iterations, threshold %.2fus", |
| 275 | scall, usec, nsamples, 1.00 * threshold / (keep_samples)); |
| 276 | |
| 277 | cur_sample = 0; |
Xiao Yang | 825459d | 2017-07-20 17:38:34 +0800 | [diff] [blame] | 278 | for (i = 0; i < (int)nsamples; i++) { |
Cyril Hrubis | c459654 | 2017-06-20 15:42:18 +0200 | [diff] [blame] | 279 | if (sample(CLOCK_MONOTONIC, usec)) { |
| 280 | tst_res(TINFO, "sampling function failed, exitting"); |
| 281 | return; |
| 282 | } |
| 283 | } |
| 284 | |
| 285 | qsort(samples, nsamples, sizeof(samples[0]), cmp); |
| 286 | |
| 287 | write_to_file(); |
| 288 | |
Xiao Yang | 825459d | 2017-07-20 17:38:34 +0800 | [diff] [blame] | 289 | for (i = 0; samples[i] > 10 * usec && i < (int)nsamples; i++) { |
Cyril Hrubis | c459654 | 2017-06-20 15:42:18 +0200 | [diff] [blame] | 290 | if (samples[i] <= 3 * monotonic_resolution) |
| 291 | break; |
| 292 | } |
| 293 | |
| 294 | if (i > 0) { |
| 295 | tst_res(TINFO, "Found %i outliners in [%lli,%lli] range", |
| 296 | i, samples[0], samples[i-1]); |
| 297 | } |
| 298 | |
Xiao Yang | 825459d | 2017-07-20 17:38:34 +0800 | [diff] [blame] | 299 | for (i = nsamples - 1; samples[i] < usec && i > -1; i--); |
Cyril Hrubis | c459654 | 2017-06-20 15:42:18 +0200 | [diff] [blame] | 300 | |
Xiao Yang | 825459d | 2017-07-20 17:38:34 +0800 | [diff] [blame] | 301 | if (i < (int)nsamples - 1) { |
Cyril Hrubis | c459654 | 2017-06-20 15:42:18 +0200 | [diff] [blame] | 302 | tst_res(TFAIL, "%s woken up early %u times range: [%lli,%lli]", |
| 303 | scall, nsamples - 1 - i, |
| 304 | samples[i+1], samples[nsamples-1]); |
| 305 | failed = 1; |
| 306 | } |
| 307 | |
| 308 | median = samples[nsamples/2]; |
| 309 | |
| 310 | trunc_mean = 0; |
| 311 | |
Xiao Yang | 825459d | 2017-07-20 17:38:34 +0800 | [diff] [blame] | 312 | for (i = discard; i < (int)nsamples; i++) |
Cyril Hrubis | c459654 | 2017-06-20 15:42:18 +0200 | [diff] [blame] | 313 | trunc_mean += samples[i]; |
| 314 | |
| 315 | tst_res(TINFO, |
| 316 | "min %llius, max %llius, median %llius, trunc mean %.2fus (discarded %u)", |
| 317 | samples[nsamples-1], samples[0], median, |
| 318 | 1.00 * trunc_mean / keep_samples, discard); |
| 319 | |
| 320 | if (trunc_mean > (nsamples - discard) * usec + threshold) { |
| 321 | tst_res(TFAIL, "%s slept for too long", scall); |
| 322 | |
| 323 | if (!print_frequency_plot) |
| 324 | frequency_plot(); |
| 325 | |
| 326 | failed = 1; |
| 327 | } |
| 328 | |
| 329 | if (print_frequency_plot) |
| 330 | frequency_plot(); |
| 331 | |
| 332 | if (!failed) |
| 333 | tst_res(TPASS, "Measured times are within thresholds"); |
| 334 | } |
| 335 | |
| 336 | static void parse_timer_opts(void); |
| 337 | |
Daniel Lezcano | 1964db7 | 2017-08-17 15:00:25 +0000 | [diff] [blame] | 338 | static int set_latency(void) |
| 339 | { |
| 340 | int fd, latency = 0; |
| 341 | |
| 342 | fd = open("/dev/cpu_dma_latency", O_WRONLY); |
| 343 | if (fd < 0) |
| 344 | return fd; |
| 345 | |
| 346 | return write(fd, &latency, sizeof(latency)); |
| 347 | } |
| 348 | |
Cyril Hrubis | c459654 | 2017-06-20 15:42:18 +0200 | [diff] [blame] | 349 | static void timer_setup(void) |
| 350 | { |
| 351 | struct timespec t; |
| 352 | int ret; |
| 353 | |
| 354 | tst_clock_getres(CLOCK_MONOTONIC, &t); |
| 355 | |
| 356 | tst_res(TINFO, "CLOCK_MONOTONIC resolution %lins", (long)t.tv_nsec); |
| 357 | |
| 358 | monotonic_resolution = t.tv_nsec / 1000; |
| 359 | timerslack = 50; |
| 360 | |
| 361 | #ifdef PR_GET_TIMERSLACK |
| 362 | ret = prctl(PR_GET_TIMERSLACK); |
| 363 | if (ret < 0) { |
| 364 | tst_res(TINFO, "prctl(PR_GET_TIMERSLACK) = -1, using %uus", |
| 365 | timerslack); |
| 366 | } else { |
| 367 | timerslack = ret / 1000; |
| 368 | tst_res(TINFO, "prctl(PR_GET_TIMERSLACK) = %ius", timerslack); |
| 369 | } |
| 370 | #else |
| 371 | tst_res(TINFO, "PR_GET_TIMERSLACK not defined, using %uus", |
| 372 | timerslack); |
| 373 | #endif /* PR_GET_TIMERSLACK */ |
| 374 | |
| 375 | parse_timer_opts(); |
| 376 | |
| 377 | samples = SAFE_MALLOC(sizeof(long long) * MAX(MAX_SAMPLES, sample_cnt)); |
| 378 | |
Daniel Lezcano | 1964db7 | 2017-08-17 15:00:25 +0000 | [diff] [blame] | 379 | if (set_latency() < 0) |
| 380 | tst_res(TINFO, "Failed to set zero latency constraint: %m"); |
| 381 | |
Cyril Hrubis | c459654 | 2017-06-20 15:42:18 +0200 | [diff] [blame] | 382 | if (setup) |
| 383 | setup(); |
| 384 | } |
| 385 | |
| 386 | static void timer_cleanup(void) |
| 387 | { |
| 388 | free(samples); |
| 389 | |
| 390 | if (cleanup) |
| 391 | cleanup(); |
| 392 | } |
| 393 | |
| 394 | static struct tst_timer_tcase { |
| 395 | long long usec; |
| 396 | unsigned int samples; |
| 397 | } tcases[] = { |
| 398 | {1000, 500}, |
| 399 | {2000, 500}, |
| 400 | {5000, 300}, |
| 401 | {10000, 100}, |
| 402 | {25000, 50}, |
| 403 | {100000, 10}, |
| 404 | {1000000, 2}, |
| 405 | }; |
| 406 | |
| 407 | static void timer_test_fn(unsigned int n) |
| 408 | { |
| 409 | do_timer_test(tcases[n].usec, tcases[n].samples); |
| 410 | } |
| 411 | |
| 412 | static void single_timer_test(void) |
| 413 | { |
| 414 | do_timer_test(sleep_time, sample_cnt); |
| 415 | } |
| 416 | |
| 417 | static struct tst_option options[] = { |
| 418 | {"p", &print_frequency_plot, "-p Print frequency plot"}, |
| 419 | {"s:", &str_sleep_time, "-s us Sleep time"}, |
| 420 | {"n:", &str_sample_cnt, "-n uint Number of samples to take"}, |
| 421 | {"f:", &file_name, "-f fname Write measured samples into a file"}, |
| 422 | {NULL, NULL, NULL} |
| 423 | }; |
| 424 | |
| 425 | static void parse_timer_opts(void) |
| 426 | { |
| 427 | if (str_sleep_time) { |
| 428 | if (tst_parse_int(str_sleep_time, &sleep_time, 0, INT_MAX)) { |
| 429 | tst_brk(TBROK, |
| 430 | "Invalid sleep time '%s'", str_sleep_time); |
| 431 | } |
| 432 | } |
| 433 | |
| 434 | if (str_sample_cnt) { |
| 435 | if (tst_parse_int(str_sample_cnt, &sample_cnt, 1, INT_MAX)) { |
| 436 | tst_brk(TBROK, |
| 437 | "Invalid sample count '%s'", str_sample_cnt); |
| 438 | } |
| 439 | } |
| 440 | |
| 441 | if (str_sleep_time || str_sample_cnt) { |
| 442 | if (sleep_time < 0) |
| 443 | sleep_time = 10000; |
| 444 | |
| 445 | if (!sample_cnt) |
| 446 | sample_cnt = 500; |
| 447 | |
| 448 | long long timeout = sleep_time * sample_cnt / 1000000; |
| 449 | |
| 450 | tst_set_timeout(timeout + timeout/10); |
| 451 | |
| 452 | test->test_all = single_timer_test; |
| 453 | test->test = NULL; |
| 454 | test->tcnt = 0; |
| 455 | } |
| 456 | } |
| 457 | |
| 458 | struct tst_test *tst_timer_test_setup(struct tst_test *timer_test) |
| 459 | { |
| 460 | setup = timer_test->setup; |
| 461 | cleanup = timer_test->cleanup; |
Li Wang | b5d620a | 2017-11-01 13:15:23 +0800 | [diff] [blame] | 462 | scall = timer_test->scall; |
Cyril Hrubis | c459654 | 2017-06-20 15:42:18 +0200 | [diff] [blame] | 463 | sample = timer_test->sample; |
| 464 | |
Li Wang | b5d620a | 2017-11-01 13:15:23 +0800 | [diff] [blame] | 465 | timer_test->scall = NULL; |
Cyril Hrubis | c459654 | 2017-06-20 15:42:18 +0200 | [diff] [blame] | 466 | timer_test->setup = timer_setup; |
| 467 | timer_test->cleanup = timer_cleanup; |
| 468 | timer_test->test = timer_test_fn; |
| 469 | timer_test->tcnt = ARRAY_SIZE(tcases); |
| 470 | timer_test->sample = NULL; |
| 471 | timer_test->options = options; |
| 472 | |
| 473 | test = timer_test; |
| 474 | |
| 475 | return timer_test; |
| 476 | } |