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b64eb60f MW |
1 | /* -*-c-*- |
2 | * | |
3 | * Benchmarking support | |
4 | * | |
5 | * (c) 2023 Straylight/Edgeware | |
6 | */ | |
7 | ||
8 | /*----- Licensing notice --------------------------------------------------* | |
9 | * | |
10 | * This file is part of the mLib utilities library. | |
11 | * | |
12 | * mLib is free software: you can redistribute it and/or modify it under | |
13 | * the terms of the GNU Library General Public License as published by | |
14 | * the Free Software Foundation; either version 2 of the License, or (at | |
15 | * your option) any later version. | |
16 | * | |
17 | * mLib is distributed in the hope that it will be useful, but WITHOUT | |
18 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
19 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public | |
20 | * License for more details. | |
21 | * | |
22 | * You should have received a copy of the GNU Library General Public | |
23 | * License along with mLib. If not, write to the Free Software | |
24 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, | |
25 | * USA. | |
26 | */ | |
27 | ||
28 | /*----- Header files ------------------------------------------------------*/ | |
29 | ||
30 | #include "config.h" | |
31 | ||
32 | #include <errno.h> | |
33 | #include <stdarg.h> | |
34 | #include <stdio.h> | |
35 | #include <stdlib.h> | |
36 | #include <string.h> | |
37 | #include <time.h> | |
38 | ||
39 | #include "alloc.h" | |
40 | #include "bench.h" | |
41 | #include "bits.h" | |
42 | #include "linreg.h" | |
43 | #include "macros.h" | |
44 | ||
45 | /*----- Data structures ---------------------------------------------------*/ | |
46 | ||
47 | struct timer { | |
48 | struct bench_timer _t; | |
49 | const struct timer_ops *clkops, *cyops; | |
50 | union { int fd; } u_cy; | |
51 | }; | |
52 | ||
53 | struct timer_ops { | |
54 | void (*now)(struct bench_time *t_out, struct timer *t); | |
55 | void (*teardown)(struct timer *t); | |
56 | }; | |
57 | ||
58 | /*----- Preliminaries -----------------------------------------------------*/ | |
59 | ||
60 | #define NS_PER_S 1000000000 | |
61 | ||
62 | static void PRINTF_LIKE(1, 2) debug(const char *fmt, ...) | |
63 | { | |
64 | const char *p; | |
65 | va_list ap; | |
66 | ||
67 | p = getenv("MLIB_BENCH_DEBUG"); | |
68 | if (p && *p != 'n' && *p != '0') { | |
69 | va_start(ap, fmt); | |
70 | fputs("mLib BENCH: ", stderr); | |
71 | vfprintf(stderr, fmt, ap); | |
72 | fputc('\n', stderr); | |
73 | va_end(ap); | |
74 | } | |
75 | } | |
76 | ||
77 | /*----- The null clock ----------------------------------------------------*/ | |
78 | ||
79 | static void null_now(struct bench_time *t_out, struct timer *t) { ; } | |
80 | static void null_teardown(struct timer *t) { ; } | |
81 | static const struct timer_ops null_ops = { null_now, null_teardown }; | |
82 | ||
83 | static int null_cyinit(struct timer *t) | |
84 | { t->cyops = &null_ops; return (0); } | |
85 | ||
86 | #define NULL_CYENT { "null", null_cyinit }, | |
87 | ||
88 | /*----- Linux performance counters ----------------------------------------*/ | |
89 | ||
90 | #if defined(HAVE_LINUX_PERF_EVENT_H) && defined(HAVE_UINT64) | |
91 | ||
92 | #include <sys/types.h> | |
93 | #include <unistd.h> | |
94 | ||
95 | #include <linux/perf_event.h> | |
96 | #include <asm/unistd.h> | |
97 | ||
98 | static void perfevent_now(struct bench_time *t_out, struct timer *t) | |
99 | { | |
100 | ssize_t n; | |
101 | ||
102 | n = read(t->u_cy.fd, &t_out->cy.i, sizeof(t_out->cy.i)); | |
103 | if (n != sizeof(t_out->cy.i)) { | |
104 | debug("failed to read perf-event counter: %s", strerror(errno)); | |
105 | return; | |
106 | } | |
107 | t_out->f |= BTF_CYOK; | |
108 | } | |
109 | ||
110 | static void perfevent_teardown(struct timer *t) | |
111 | { close(t->u_cy.fd); } | |
112 | ||
113 | static const struct timer_ops perfevent_ops = | |
114 | { perfevent_now, perfevent_teardown }; | |
115 | ||
116 | static int perfevent_init(struct timer *t) | |
117 | { | |
118 | struct perf_event_attr attr = { 0 }; | |
119 | struct bench_time tm; | |
120 | ||
121 | attr.type = PERF_TYPE_HARDWARE; | |
122 | attr.size = sizeof(attr); | |
123 | attr.config = PERF_COUNT_HW_CPU_CYCLES; | |
124 | attr.disabled = 0; | |
125 | attr.exclude_kernel = 1; | |
126 | attr.exclude_hv = 1; | |
127 | ||
128 | t->u_cy.fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0); | |
129 | if (t->u_cy.fd < 0) { | |
130 | debug("couldn't open perf evvent: %s", strerror(errno)); | |
131 | return (-1); | |
132 | } | |
133 | ||
134 | tm.f = 0; perfevent_now(&tm, t); | |
135 | if (!(tm.f&BTF_CYOK)) { close(t->u_cy.fd); return (-1); } | |
136 | ||
137 | t->cyops = &perfevent_ops; return (0); | |
138 | } | |
139 | # define PERFEVENT_CYENT { "linux-perf-event", perfevent_init }, | |
140 | #else | |
141 | # define PERFEVENT_CYENT | |
142 | #endif | |
143 | ||
144 | /*----- Intel time-stamp counter ------------------------------------------*/ | |
145 | ||
146 | #if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) | |
147 | ||
148 | #define EFLAGS_ID (1u << 21) | |
149 | #define CPUID_1D_TSC (1u << 4) | |
150 | ||
151 | static uint32 set_flags(unsigned long m, unsigned long x) | |
152 | { | |
153 | unsigned long r; | |
154 | ||
155 | #ifdef __x86_64__ | |
156 | # define TMP "%%rcx" | |
157 | #else | |
158 | # define TMP "%%ecx" | |
159 | #endif | |
160 | ||
161 | __asm__ ("pushf\n\t" | |
162 | "pop %0\n\t" | |
163 | "mov %0, " TMP "\n\t" | |
164 | "and %1, %0\n\t" | |
165 | "xor %2, %0\n\t" | |
166 | "push %0\n\t" | |
167 | "popf\n\t" | |
168 | "pushf\n\t" | |
169 | "pop %0\n\t" | |
170 | "push " TMP "\n\t" | |
171 | "popf" | |
172 | : "=r"(r) | |
173 | : "g"(m), "g"(x) | |
174 | : "ecx"); | |
175 | return (r); | |
176 | } | |
177 | ||
178 | struct cpuid { uint32 a, b, c, d; }; | |
179 | ||
180 | static void cpuid(struct cpuid *info_out, uint32 a, uint32 c) | |
181 | { | |
182 | __asm__ ("movl %1, %%eax\n\t" | |
183 | "movl %2, %%ecx\n\t" | |
184 | "cpuid\n\t" | |
185 | "movl %%eax, 0(%0)\n\t" | |
186 | "movl %%ebx, 4(%0)\n\t" | |
187 | "movl %%ecx, 8(%0)\n\t" | |
188 | "movl %%edx, 12(%0)\n\t" | |
189 | : /* no outputs */ | |
190 | : "r"(info_out), "g"(a), "g"(c) | |
191 | : "eax", "ebx", "ecx", "edx", "cc"); | |
192 | } | |
193 | ||
194 | static void x86rdtsc_now(struct bench_time *t_out, struct timer *t) | |
195 | { | |
196 | uint32 lo, hi; | |
197 | ||
198 | __asm__ __volatile__ ("rdtsc" : "=a"(lo), "=d"(hi)); | |
199 | SET64(t_out->cy, hi, lo); t_out->f |= BTF_CYOK; | |
200 | } | |
201 | ||
202 | static const struct timer_ops x86rdtsc_ops = | |
203 | { x86rdtsc_now, null_teardown }; | |
204 | ||
205 | static int x86rdtsc_init(struct timer *t) | |
206 | { | |
207 | struct cpuid info; | |
208 | ||
209 | if ((set_flags(~EFLAGS_ID, 0)&EFLAGS_ID) || | |
210 | !(set_flags(~EFLAGS_ID, EFLAGS_ID)&EFLAGS_ID)) | |
211 | { debug("no `cpuid' instruction"); return (-1); } | |
212 | cpuid(&info, 0, 0); | |
213 | if (info.a < 1) { debug("no `cpuid' leaf 1"); return (-1); } | |
214 | cpuid(&info, 1, 0); | |
215 | if (!(info.d&CPUID_1D_TSC)) | |
216 | { debug("no `rdtsc' instrunction"); return (-1); } | |
217 | t->cyops = &x86rdtsc_ops; return (0); | |
218 | } | |
219 | ||
220 | # define X86RDTSC_CYENT { "x86-rdtsc", x86rdtsc_init }, | |
221 | #else | |
222 | # define X86RDTWC_CYENT | |
223 | #endif | |
224 | ||
225 | /*----- POSIX `clock_gettime' ---------------------------------------------*/ | |
226 | ||
227 | #if defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_THREAD_CPUTIME_ID) | |
228 | ||
229 | static void gettime_now(struct bench_time *t_out, struct timer *t) | |
230 | { | |
231 | struct timespec now; | |
232 | ||
233 | if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, &now)) | |
234 | { debug("error reading POSIX clock: %s", strerror(errno)); return; } | |
235 | ASSIGN64(t_out->s, now.tv_sec); t_out->ns = now.tv_nsec; | |
236 | t_out->f |= BTF_TIMEOK; | |
237 | } | |
238 | ||
239 | static const struct timer_ops gettime_ops = { gettime_now, null_teardown }; | |
240 | ||
241 | static int gettime_init(struct timer *t) | |
242 | { | |
243 | struct bench_time tm; | |
244 | ||
245 | tm.f = 0; gettime_now(&tm, t); if (!tm.f&BTF_TIMEOK) return (-1); | |
246 | t->clkops = &gettime_ops; return (0); | |
247 | } | |
248 | ||
249 | # define GETTIME_CLKENT { "posix-clock_gettime", gettime_init }, | |
250 | #else | |
251 | # define GETTIME_CLKENT | |
252 | #endif | |
253 | ||
254 | /*----- Standard C `clock' ------------------------------------------------*/ | |
255 | ||
256 | static void clock_now(struct bench_time *t_out, struct timer *t) | |
257 | { | |
258 | clock_t now, x; | |
259 | unsigned long s; uint32 ns; | |
260 | ||
261 | now = clock(); | |
262 | if (now == (clock_t)-1) { | |
263 | debug("error reading standard clock: %s", strerror(errno)); | |
264 | return; | |
265 | } | |
266 | x = now/CLOCKS_PER_SEC; | |
267 | if (x > ULONG_MAX) { debug("standard clock out of range"); return; } | |
268 | ||
269 | s = x; x = now - CLOCKS_PER_SEC*s; | |
270 | if (!(NS_PER_S%CLOCKS_PER_SEC)) | |
271 | ns = x*(NS_PER_S/CLOCKS_PER_SEC); | |
272 | else if (NS_PER_S <= ULONG_MAX/CLOCKS_PER_SEC) | |
273 | ns = (x*NS_PER_S)/CLOCKS_PER_SEC; | |
274 | else | |
275 | ns = x*((NS_PER_S + 0.0)/CLOCKS_PER_SEC); | |
276 | ASSIGN64(t_out->s, s); t_out->ns = ns; t_out->f |= BTF_TIMEOK; | |
277 | } | |
278 | ||
279 | static const struct timer_ops clock_ops = { clock_now, null_teardown }; | |
280 | ||
281 | static int clock_init(struct timer *t) | |
282 | { | |
283 | struct bench_time tm; | |
284 | ||
285 | tm.f = 0; clock_now(&tm, t); if (!tm.f&BTF_TIMEOK) return (-1); | |
286 | t->clkops = &clock_ops; return (0); | |
287 | } | |
288 | ||
289 | #define CLOCK_CLKENT { "clock", clock_init }, | |
290 | ||
291 | /*----- Timing setup ------------------------------------------------------*/ | |
292 | ||
293 | static const struct timerent { | |
294 | const char *name; | |
295 | int (*init)(struct timer */*t*/); | |
296 | } | |
297 | clktab[] = { GETTIME_CLKENT CLOCK_CLKENT { 0, 0 } }, | |
298 | cytab[] = { PERFEVENT_CYENT X86RDTSC_CYENT NULL_CYENT { 0, 0 } }; | |
299 | ||
300 | static const struct timerent *find_timer_n(const char *name, size_t sz, | |
301 | const struct timerent *timers, | |
302 | const char *what) | |
303 | { | |
304 | while (timers->name) { | |
305 | if (strlen(timers->name) == sz && MEMCMP(name, ==, timers->name, sz)) | |
306 | return (timers); | |
307 | timers++; | |
308 | } | |
309 | debug("%s timer `%.*s' not found", what, (int)sz, name); return (0); | |
310 | } | |
311 | ||
312 | static int try_timer(struct timer *t, | |
313 | const struct timerent *timer, const char *what) | |
314 | { | |
315 | if (timer->init(t)) return (-1); | |
316 | debug("selected %s timer `%s'", what, timer->name); return (0); | |
317 | } | |
318 | ||
319 | static int select_timer(struct timer *t, const struct timerent *timers, | |
320 | const char *varname, const char *what) | |
321 | { | |
322 | const char *p; size_t n; | |
323 | const struct timerent *timer; | |
324 | ||
325 | p = getenv(varname); | |
326 | if (!p) { | |
327 | while (timers->name) | |
328 | if (!try_timer(t, timers++, what)) return (0); | |
329 | } else { | |
330 | for (;;) { | |
331 | n = strcspn(p, ","); | |
332 | timer = find_timer_n(p, n, timers, what); | |
333 | if (timer && !try_timer(t, timer, what)) return (0); | |
334 | if (!p[n]) break; | |
335 | p += n + 1; | |
336 | } | |
337 | } | |
338 | debug("no suitable %s timer found", what); return (-1); | |
339 | } | |
340 | ||
341 | static void timer_now(struct bench_timer *tm, struct bench_time *t_out) | |
342 | { | |
343 | struct timer *t = (struct timer *)tm; | |
344 | ||
345 | t->clkops->now(t_out, t); | |
346 | t->cyops->now(t_out, t); | |
347 | } | |
348 | ||
349 | static void timer_destroy(struct bench_timer *tm) | |
350 | { | |
351 | struct timer *t = (struct timer *)tm; | |
352 | ||
353 | if (!t) return; | |
354 | if (t->clkops) t->clkops->teardown(t); | |
355 | if (t->cyops) t->cyops->teardown(t); | |
356 | xfree(t); | |
357 | } | |
358 | ||
359 | static const struct bench_timerops timer_ops = { timer_now, timer_destroy }; | |
360 | ||
361 | struct bench_timer *bench_createtimer(void) | |
362 | { | |
363 | struct timer *t = 0; | |
364 | struct bench_timer *ret = 0; | |
365 | ||
366 | t = xmalloc(sizeof(*t)); t->cyops = 0; t->clkops = 0; | |
367 | if (select_timer(t, clktab, "MLIB_BENCH_CLKTIMER", "clock")) goto end; | |
368 | if (select_timer(t, cytab, "MLIB_BENCH_CYCLETIMER", "cycle")) goto end; | |
369 | t->_t.ops = &timer_ops; ret = &t->_t; t = 0; | |
370 | end: | |
371 | if (t) timer_destroy(&t->_t); | |
372 | return (ret); | |
373 | } | |
374 | ||
375 | #ifdef HAVE_UINT64 | |
376 | # define FLOATK64(k) ((double)(k).i) | |
377 | #else | |
378 | # define FLOATK64(k) ((double)(k).lo + 4275123318.0*(double)(k).hi) | |
379 | #endif | |
380 | ||
381 | static void timer_diff(struct bench_timing *delta_out, | |
382 | const struct bench_time *t0, | |
383 | const struct bench_time *t1) | |
384 | { | |
385 | delta_out->f = t0->f&t1->f; | |
386 | kludge64 k; | |
387 | ||
388 | if (!(delta_out->f&BTF_TIMEOK)) | |
389 | delta_out->t = 0.0; | |
390 | else { | |
391 | SUB64(k, t1->s, t0->s); | |
392 | delta_out->t = FLOATK64(k) - 1 + | |
393 | (t1->ns + NS_PER_S - t0->ns)/(double)NS_PER_S; | |
394 | } | |
395 | ||
396 | if (!(delta_out->f&BTF_CYOK)) | |
397 | delta_out->cy = 0.0; | |
398 | else { | |
399 | SUB64(k, t1->cy, t0->cy); | |
400 | delta_out->cy = FLOATK64(k); | |
401 | } | |
402 | } | |
403 | ||
404 | /*----- Calibration -------------------------------------------------------*/ | |
405 | ||
406 | void bench_init(struct bench_state *b, struct bench_timer *tm) | |
407 | { b->tm = tm; b->target_s = 1.0; b->f = 0; } | |
408 | ||
409 | void bench_destroy(struct bench_state *b) | |
410 | { b->tm->ops->destroy(b->tm); } | |
411 | ||
412 | static void do_nothing(unsigned long n, void *p) | |
413 | { while (n--) RELAX; } | |
414 | ||
415 | int bench_calibrate(struct bench_state *b) | |
416 | { | |
417 | struct linreg lr_clk = LINREG_INIT, lr_cy = LINREG_INIT; | |
418 | unsigned long n; | |
419 | unsigned i; | |
420 | struct bench_timer *tm = b->tm; | |
421 | struct bench_time t0, t1; | |
422 | struct bench_timing delta; | |
423 | bench_fn *fn = LAUNDER(&do_nothing); | |
424 | unsigned f = BTF_ANY; | |
425 | int rc; | |
426 | ||
427 | if (b->f&BTF_ANY) return (0); | |
428 | ||
429 | for (i = 0; i < 10; i++) | |
430 | { tm->ops->now(tm, &t0); fn(1, 0); tm->ops->now(tm, &t1); } | |
431 | ||
432 | debug("calibrating..."); | |
433 | n = 1; | |
434 | for (;;) { | |
435 | tm->ops->now(tm, &t0); fn(n, 0); tm->ops->now(tm, &t1); | |
436 | timer_diff(&delta, &t0, &t1); f &= delta.f; | |
437 | if (!(f&BTF_TIMEOK)) { rc = -1; goto end; } | |
438 | linreg_update(&lr_clk, n, delta.t); | |
439 | if (!(f&BTF_CYOK)) | |
440 | debug(" n = %10lu; t = %12g s", n, delta.t); | |
441 | else { | |
442 | linreg_update(&lr_cy, n, delta.cy); | |
443 | debug(" n = %10lu; t = %12g s, cy = %10.0f", n, delta.t, delta.cy); | |
444 | } | |
445 | if (delta.t >= b->target_s/20.0) break; | |
446 | if (n >= ULONG_MAX - n/3) break; | |
447 | n += n/3 + 1; | |
448 | } | |
449 | ||
450 | linreg_fit(&lr_clk, &b->clk.m, &b->clk.c, 0); | |
451 | debug("clock overhead = (%g n + %g) s", b->clk.m, b->clk.c); | |
452 | if (f&BTF_CYOK) { | |
453 | linreg_fit(&lr_clk, &b->clk.m, &b->clk.c, 0); | |
454 | debug("cycle overhead = (%g n + %g) cy", b->cy.m, b->cy.c); | |
455 | } | |
456 | b->f |= f; rc = 0; | |
457 | end: | |
458 | return (rc); | |
459 | } | |
460 | ||
461 | int bench_measure(struct bench_timing *t_out, struct bench_state *b, | |
e63124bc | 462 | double base, bench_fn *fn, void *p) |
b64eb60f MW |
463 | { |
464 | struct bench_timer *tm = b->tm; | |
465 | struct bench_time t0, t1; | |
466 | unsigned long n; | |
467 | ||
468 | if (bench_calibrate(b)) return (-1); | |
469 | debug("measuring..."); n = 1; | |
470 | for (;;) { | |
471 | tm->ops->now(tm, &t0); fn(n, p); tm->ops->now(tm, &t1); | |
472 | timer_diff(t_out, &t0, &t1); | |
473 | if (!(t_out->f&BTF_TIMEOK)) return (-1); | |
474 | if (!(t_out->f&BTF_CYOK)) debug(" n = %10lu; t = %12g", n, t_out->t); | |
475 | else debug(" n = %10lu; t = %12g, cy = %10.0f", n, t_out->t, t_out->cy); | |
476 | if (t_out->t >= 0.72*b->target_s) break; | |
477 | n *= 1.44*b->target_s/t_out->t; | |
478 | } | |
c7da785d MW |
479 | t_out->t -= n*b->clk.m + b->clk.c; |
480 | if (t_out->f&BTF_CYOK) t_out->cy -= n*b->cy.m + b->cy.c; | |
481 | if (!(t_out->f&BTF_CYOK)) debug(" adjusted t' = %12g", t_out->t); | |
482 | else debug(" adjusted t = %12g, cy = %10.0f", t_out->t, t_out->cy); | |
b64eb60f MW |
483 | if (!(t_out->f&BTF_CYOK)) |
484 | debug(" %g s per op; %g ops/s", t_out->t/n, n/t_out->t); | |
485 | else | |
486 | debug(" %g s (%g cy) per op; %g ops/s", | |
487 | t_out->t/n, t_out->cy/n, n/t_out->t); | |
e63124bc | 488 | t_out->n = n*base; return (0); |
b64eb60f MW |
489 | } |
490 | ||
491 | /*----- That's all, folks -------------------------------------------------*/ |