1 /* 2 * fp-bench.c - A collection of simple floating point microbenchmarks. 3 * 4 * Copyright (C) 2018, Emilio G. Cota <cota@braap.org> 5 * 6 * License: GNU GPL, version 2 or later. 7 * See the COPYING file in the top-level directory. 8 */ 9 #ifndef HW_POISON_H 10 #error Must define HW_POISON_H to work around TARGET_* poisoning 11 #endif 12 13 #include "qemu/osdep.h" 14 #include <math.h> 15 #include <fenv.h> 16 #include "qemu/timer.h" 17 #include "fpu/softfloat.h" 18 19 /* amortize the computation of random inputs */ 20 #define OPS_PER_ITER 50000 21 22 #define MAX_OPERANDS 3 23 24 #define SEED_A 0xdeadfacedeadface 25 #define SEED_B 0xbadc0feebadc0fee 26 #define SEED_C 0xbeefdeadbeefdead 27 28 enum op { 29 OP_ADD, 30 OP_SUB, 31 OP_MUL, 32 OP_DIV, 33 OP_FMA, 34 OP_SQRT, 35 OP_CMP, 36 OP_MAX_NR, 37 }; 38 39 static const char * const op_names[] = { 40 [OP_ADD] = "add", 41 [OP_SUB] = "sub", 42 [OP_MUL] = "mul", 43 [OP_DIV] = "div", 44 [OP_FMA] = "mulAdd", 45 [OP_SQRT] = "sqrt", 46 [OP_CMP] = "cmp", 47 [OP_MAX_NR] = NULL, 48 }; 49 50 enum precision { 51 PREC_SINGLE, 52 PREC_DOUBLE, 53 PREC_FLOAT32, 54 PREC_FLOAT64, 55 PREC_MAX_NR, 56 }; 57 58 enum rounding { 59 ROUND_EVEN, 60 ROUND_ZERO, 61 ROUND_DOWN, 62 ROUND_UP, 63 ROUND_TIEAWAY, 64 N_ROUND_MODES, 65 }; 66 67 static const char * const round_names[] = { 68 [ROUND_EVEN] = "even", 69 [ROUND_ZERO] = "zero", 70 [ROUND_DOWN] = "down", 71 [ROUND_UP] = "up", 72 [ROUND_TIEAWAY] = "tieaway", 73 }; 74 75 enum tester { 76 TESTER_SOFT, 77 TESTER_HOST, 78 TESTER_MAX_NR, 79 }; 80 81 static const char * const tester_names[] = { 82 [TESTER_SOFT] = "soft", 83 [TESTER_HOST] = "host", 84 [TESTER_MAX_NR] = NULL, 85 }; 86 87 union fp { 88 float f; 89 double d; 90 float32 f32; 91 float64 f64; 92 uint64_t u64; 93 }; 94 95 struct op_state; 96 97 typedef float (*float_func_t)(const struct op_state *s); 98 typedef double (*double_func_t)(const struct op_state *s); 99 100 union fp_func { 101 float_func_t float_func; 102 double_func_t double_func; 103 }; 104 105 typedef void (*bench_func_t)(void); 106 107 struct op_desc { 108 const char * const name; 109 }; 110 111 #define DEFAULT_DURATION_SECS 1 112 113 static uint64_t random_ops[MAX_OPERANDS] = { 114 SEED_A, SEED_B, SEED_C, 115 }; 116 static float_status soft_status; 117 static enum precision precision; 118 static enum op operation; 119 static enum tester tester; 120 static uint64_t n_completed_ops; 121 static unsigned int duration = DEFAULT_DURATION_SECS; 122 static int64_t ns_elapsed; 123 /* disable optimizations with volatile */ 124 static volatile union fp res; 125 126 /* 127 * From: https://en.wikipedia.org/wiki/Xorshift 128 * This is faster than rand_r(), and gives us a wider range (RAND_MAX is only 129 * guaranteed to be >= INT_MAX). 130 */ 131 static uint64_t xorshift64star(uint64_t x) 132 { 133 x ^= x >> 12; /* a */ 134 x ^= x << 25; /* b */ 135 x ^= x >> 27; /* c */ 136 return x * UINT64_C(2685821657736338717); 137 } 138 139 static void update_random_ops(int n_ops, enum precision prec) 140 { 141 int i; 142 143 for (i = 0; i < n_ops; i++) { 144 uint64_t r = random_ops[i]; 145 146 switch (prec) { 147 case PREC_SINGLE: 148 case PREC_FLOAT32: 149 do { 150 r = xorshift64star(r); 151 } while (!float32_is_normal(r)); 152 break; 153 case PREC_DOUBLE: 154 case PREC_FLOAT64: 155 do { 156 r = xorshift64star(r); 157 } while (!float64_is_normal(r)); 158 break; 159 default: 160 g_assert_not_reached(); 161 } 162 random_ops[i] = r; 163 } 164 } 165 166 static void fill_random(union fp *ops, int n_ops, enum precision prec, 167 bool no_neg) 168 { 169 int i; 170 171 for (i = 0; i < n_ops; i++) { 172 switch (prec) { 173 case PREC_SINGLE: 174 case PREC_FLOAT32: 175 ops[i].f32 = make_float32(random_ops[i]); 176 if (no_neg && float32_is_neg(ops[i].f32)) { 177 ops[i].f32 = float32_chs(ops[i].f32); 178 } 179 break; 180 case PREC_DOUBLE: 181 case PREC_FLOAT64: 182 ops[i].f64 = make_float64(random_ops[i]); 183 if (no_neg && float64_is_neg(ops[i].f64)) { 184 ops[i].f64 = float64_chs(ops[i].f64); 185 } 186 break; 187 default: 188 g_assert_not_reached(); 189 } 190 } 191 } 192 193 /* 194 * The main benchmark function. Instead of (ab)using macros, we rely 195 * on the compiler to unfold this at compile-time. 196 */ 197 static void bench(enum precision prec, enum op op, int n_ops, bool no_neg) 198 { 199 int64_t tf = get_clock() + duration * 1000000000LL; 200 201 while (get_clock() < tf) { 202 union fp ops[MAX_OPERANDS]; 203 int64_t t0; 204 int i; 205 206 update_random_ops(n_ops, prec); 207 switch (prec) { 208 case PREC_SINGLE: 209 fill_random(ops, n_ops, prec, no_neg); 210 t0 = get_clock(); 211 for (i = 0; i < OPS_PER_ITER; i++) { 212 float a = ops[0].f; 213 float b = ops[1].f; 214 float c = ops[2].f; 215 216 switch (op) { 217 case OP_ADD: 218 res.f = a + b; 219 break; 220 case OP_SUB: 221 res.f = a - b; 222 break; 223 case OP_MUL: 224 res.f = a * b; 225 break; 226 case OP_DIV: 227 res.f = a / b; 228 break; 229 case OP_FMA: 230 res.f = fmaf(a, b, c); 231 break; 232 case OP_SQRT: 233 res.f = sqrtf(a); 234 break; 235 case OP_CMP: 236 res.u64 = isgreater(a, b); 237 break; 238 default: 239 g_assert_not_reached(); 240 } 241 } 242 break; 243 case PREC_DOUBLE: 244 fill_random(ops, n_ops, prec, no_neg); 245 t0 = get_clock(); 246 for (i = 0; i < OPS_PER_ITER; i++) { 247 double a = ops[0].d; 248 double b = ops[1].d; 249 double c = ops[2].d; 250 251 switch (op) { 252 case OP_ADD: 253 res.d = a + b; 254 break; 255 case OP_SUB: 256 res.d = a - b; 257 break; 258 case OP_MUL: 259 res.d = a * b; 260 break; 261 case OP_DIV: 262 res.d = a / b; 263 break; 264 case OP_FMA: 265 res.d = fma(a, b, c); 266 break; 267 case OP_SQRT: 268 res.d = sqrt(a); 269 break; 270 case OP_CMP: 271 res.u64 = isgreater(a, b); 272 break; 273 default: 274 g_assert_not_reached(); 275 } 276 } 277 break; 278 case PREC_FLOAT32: 279 fill_random(ops, n_ops, prec, no_neg); 280 t0 = get_clock(); 281 for (i = 0; i < OPS_PER_ITER; i++) { 282 float32 a = ops[0].f32; 283 float32 b = ops[1].f32; 284 float32 c = ops[2].f32; 285 286 switch (op) { 287 case OP_ADD: 288 res.f32 = float32_add(a, b, &soft_status); 289 break; 290 case OP_SUB: 291 res.f32 = float32_sub(a, b, &soft_status); 292 break; 293 case OP_MUL: 294 res.f = float32_mul(a, b, &soft_status); 295 break; 296 case OP_DIV: 297 res.f32 = float32_div(a, b, &soft_status); 298 break; 299 case OP_FMA: 300 res.f32 = float32_muladd(a, b, c, 0, &soft_status); 301 break; 302 case OP_SQRT: 303 res.f32 = float32_sqrt(a, &soft_status); 304 break; 305 case OP_CMP: 306 res.u64 = float32_compare_quiet(a, b, &soft_status); 307 break; 308 default: 309 g_assert_not_reached(); 310 } 311 } 312 break; 313 case PREC_FLOAT64: 314 fill_random(ops, n_ops, prec, no_neg); 315 t0 = get_clock(); 316 for (i = 0; i < OPS_PER_ITER; i++) { 317 float64 a = ops[0].f64; 318 float64 b = ops[1].f64; 319 float64 c = ops[2].f64; 320 321 switch (op) { 322 case OP_ADD: 323 res.f64 = float64_add(a, b, &soft_status); 324 break; 325 case OP_SUB: 326 res.f64 = float64_sub(a, b, &soft_status); 327 break; 328 case OP_MUL: 329 res.f = float64_mul(a, b, &soft_status); 330 break; 331 case OP_DIV: 332 res.f64 = float64_div(a, b, &soft_status); 333 break; 334 case OP_FMA: 335 res.f64 = float64_muladd(a, b, c, 0, &soft_status); 336 break; 337 case OP_SQRT: 338 res.f64 = float64_sqrt(a, &soft_status); 339 break; 340 case OP_CMP: 341 res.u64 = float64_compare_quiet(a, b, &soft_status); 342 break; 343 default: 344 g_assert_not_reached(); 345 } 346 } 347 break; 348 default: 349 g_assert_not_reached(); 350 } 351 ns_elapsed += get_clock() - t0; 352 n_completed_ops += OPS_PER_ITER; 353 } 354 } 355 356 #define GEN_BENCH(name, type, prec, op, n_ops) \ 357 static void __attribute__((flatten)) name(void) \ 358 { \ 359 bench(prec, op, n_ops, false); \ 360 } 361 362 #define GEN_BENCH_NO_NEG(name, type, prec, op, n_ops) \ 363 static void __attribute__((flatten)) name(void) \ 364 { \ 365 bench(prec, op, n_ops, true); \ 366 } 367 368 #define GEN_BENCH_ALL_TYPES(opname, op, n_ops) \ 369 GEN_BENCH(bench_ ## opname ## _float, float, PREC_SINGLE, op, n_ops) \ 370 GEN_BENCH(bench_ ## opname ## _double, double, PREC_DOUBLE, op, n_ops) \ 371 GEN_BENCH(bench_ ## opname ## _float32, float32, PREC_FLOAT32, op, n_ops) \ 372 GEN_BENCH(bench_ ## opname ## _float64, float64, PREC_FLOAT64, op, n_ops) 373 374 GEN_BENCH_ALL_TYPES(add, OP_ADD, 2) 375 GEN_BENCH_ALL_TYPES(sub, OP_SUB, 2) 376 GEN_BENCH_ALL_TYPES(mul, OP_MUL, 2) 377 GEN_BENCH_ALL_TYPES(div, OP_DIV, 2) 378 GEN_BENCH_ALL_TYPES(fma, OP_FMA, 3) 379 GEN_BENCH_ALL_TYPES(cmp, OP_CMP, 2) 380 #undef GEN_BENCH_ALL_TYPES 381 382 #define GEN_BENCH_ALL_TYPES_NO_NEG(name, op, n) \ 383 GEN_BENCH_NO_NEG(bench_ ## name ## _float, float, PREC_SINGLE, op, n) \ 384 GEN_BENCH_NO_NEG(bench_ ## name ## _double, double, PREC_DOUBLE, op, n) \ 385 GEN_BENCH_NO_NEG(bench_ ## name ## _float32, float32, PREC_FLOAT32, op, n) \ 386 GEN_BENCH_NO_NEG(bench_ ## name ## _float64, float64, PREC_FLOAT64, op, n) 387 388 GEN_BENCH_ALL_TYPES_NO_NEG(sqrt, OP_SQRT, 1) 389 #undef GEN_BENCH_ALL_TYPES_NO_NEG 390 391 #undef GEN_BENCH_NO_NEG 392 #undef GEN_BENCH 393 394 #define GEN_BENCH_FUNCS(opname, op) \ 395 [op] = { \ 396 [PREC_SINGLE] = bench_ ## opname ## _float, \ 397 [PREC_DOUBLE] = bench_ ## opname ## _double, \ 398 [PREC_FLOAT32] = bench_ ## opname ## _float32, \ 399 [PREC_FLOAT64] = bench_ ## opname ## _float64, \ 400 } 401 402 static const bench_func_t bench_funcs[OP_MAX_NR][PREC_MAX_NR] = { 403 GEN_BENCH_FUNCS(add, OP_ADD), 404 GEN_BENCH_FUNCS(sub, OP_SUB), 405 GEN_BENCH_FUNCS(mul, OP_MUL), 406 GEN_BENCH_FUNCS(div, OP_DIV), 407 GEN_BENCH_FUNCS(fma, OP_FMA), 408 GEN_BENCH_FUNCS(sqrt, OP_SQRT), 409 GEN_BENCH_FUNCS(cmp, OP_CMP), 410 }; 411 412 #undef GEN_BENCH_FUNCS 413 414 static void run_bench(void) 415 { 416 bench_func_t f; 417 418 f = bench_funcs[operation][precision]; 419 g_assert(f); 420 f(); 421 } 422 423 /* @arr must be NULL-terminated */ 424 static int find_name(const char * const *arr, const char *name) 425 { 426 int i; 427 428 for (i = 0; arr[i] != NULL; i++) { 429 if (strcmp(name, arr[i]) == 0) { 430 return i; 431 } 432 } 433 return -1; 434 } 435 436 static void usage_complete(int argc, char *argv[]) 437 { 438 gchar *op_list = g_strjoinv(", ", (gchar **)op_names); 439 gchar *tester_list = g_strjoinv(", ", (gchar **)tester_names); 440 441 fprintf(stderr, "Usage: %s [options]\n", argv[0]); 442 fprintf(stderr, "options:\n"); 443 fprintf(stderr, " -d = duration, in seconds. Default: %d\n", 444 DEFAULT_DURATION_SECS); 445 fprintf(stderr, " -h = show this help message.\n"); 446 fprintf(stderr, " -o = floating point operation (%s). Default: %s\n", 447 op_list, op_names[0]); 448 fprintf(stderr, " -p = floating point precision (single, double). " 449 "Default: single\n"); 450 fprintf(stderr, " -r = rounding mode (even, zero, down, up, tieaway). " 451 "Default: even\n"); 452 fprintf(stderr, " -t = tester (%s). Default: %s\n", 453 tester_list, tester_names[0]); 454 fprintf(stderr, " -z = flush inputs to zero (soft tester only). " 455 "Default: disabled\n"); 456 fprintf(stderr, " -Z = flush output to zero (soft tester only). " 457 "Default: disabled\n"); 458 459 g_free(tester_list); 460 g_free(op_list); 461 } 462 463 static int round_name_to_mode(const char *name) 464 { 465 int i; 466 467 for (i = 0; i < N_ROUND_MODES; i++) { 468 if (!strcmp(round_names[i], name)) { 469 return i; 470 } 471 } 472 return -1; 473 } 474 475 static void QEMU_NORETURN die_host_rounding(enum rounding rounding) 476 { 477 fprintf(stderr, "fatal: '%s' rounding not supported on this host\n", 478 round_names[rounding]); 479 exit(EXIT_FAILURE); 480 } 481 482 static void set_host_precision(enum rounding rounding) 483 { 484 int rhost; 485 486 switch (rounding) { 487 case ROUND_EVEN: 488 rhost = FE_TONEAREST; 489 break; 490 case ROUND_ZERO: 491 rhost = FE_TOWARDZERO; 492 break; 493 case ROUND_DOWN: 494 rhost = FE_DOWNWARD; 495 break; 496 case ROUND_UP: 497 rhost = FE_UPWARD; 498 break; 499 case ROUND_TIEAWAY: 500 die_host_rounding(rounding); 501 return; 502 default: 503 g_assert_not_reached(); 504 } 505 506 if (fesetround(rhost)) { 507 die_host_rounding(rounding); 508 } 509 } 510 511 static void set_soft_precision(enum rounding rounding) 512 { 513 signed char mode; 514 515 switch (rounding) { 516 case ROUND_EVEN: 517 mode = float_round_nearest_even; 518 break; 519 case ROUND_ZERO: 520 mode = float_round_to_zero; 521 break; 522 case ROUND_DOWN: 523 mode = float_round_down; 524 break; 525 case ROUND_UP: 526 mode = float_round_up; 527 break; 528 case ROUND_TIEAWAY: 529 mode = float_round_ties_away; 530 break; 531 default: 532 g_assert_not_reached(); 533 } 534 soft_status.float_rounding_mode = mode; 535 } 536 537 static void parse_args(int argc, char *argv[]) 538 { 539 int c; 540 int val; 541 int rounding = ROUND_EVEN; 542 543 for (;;) { 544 c = getopt(argc, argv, "d:ho:p:r:t:zZ"); 545 if (c < 0) { 546 break; 547 } 548 switch (c) { 549 case 'd': 550 duration = atoi(optarg); 551 break; 552 case 'h': 553 usage_complete(argc, argv); 554 exit(EXIT_SUCCESS); 555 case 'o': 556 val = find_name(op_names, optarg); 557 if (val < 0) { 558 fprintf(stderr, "Unsupported op '%s'\n", optarg); 559 exit(EXIT_FAILURE); 560 } 561 operation = val; 562 break; 563 case 'p': 564 if (!strcmp(optarg, "single")) { 565 precision = PREC_SINGLE; 566 } else if (!strcmp(optarg, "double")) { 567 precision = PREC_DOUBLE; 568 } else { 569 fprintf(stderr, "Unsupported precision '%s'\n", optarg); 570 exit(EXIT_FAILURE); 571 } 572 break; 573 case 'r': 574 rounding = round_name_to_mode(optarg); 575 if (rounding < 0) { 576 fprintf(stderr, "fatal: invalid rounding mode '%s'\n", optarg); 577 exit(EXIT_FAILURE); 578 } 579 break; 580 case 't': 581 val = find_name(tester_names, optarg); 582 if (val < 0) { 583 fprintf(stderr, "Unsupported tester '%s'\n", optarg); 584 exit(EXIT_FAILURE); 585 } 586 tester = val; 587 break; 588 case 'z': 589 soft_status.flush_inputs_to_zero = 1; 590 break; 591 case 'Z': 592 soft_status.flush_to_zero = 1; 593 break; 594 } 595 } 596 597 /* set precision and rounding mode based on the tester */ 598 switch (tester) { 599 case TESTER_HOST: 600 set_host_precision(rounding); 601 break; 602 case TESTER_SOFT: 603 set_soft_precision(rounding); 604 switch (precision) { 605 case PREC_SINGLE: 606 precision = PREC_FLOAT32; 607 break; 608 case PREC_DOUBLE: 609 precision = PREC_FLOAT64; 610 break; 611 default: 612 g_assert_not_reached(); 613 } 614 break; 615 default: 616 g_assert_not_reached(); 617 } 618 } 619 620 static void pr_stats(void) 621 { 622 printf("%.2f MFlops\n", (double)n_completed_ops / ns_elapsed * 1e3); 623 } 624 625 int main(int argc, char *argv[]) 626 { 627 parse_args(argc, argv); 628 run_bench(); 629 pr_stats(); 630 return 0; 631 } 632