mirror of
https://github.com/anrieff/libcpuid
synced 2024-12-16 16:35:45 +00:00
320 lines
9 KiB
C
320 lines
9 KiB
C
/*
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* Copyright 2008 Veselin Georgiev,
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* anrieffNOSPAM @ mgail_DOT.com (convert to gmail)
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdio.h>
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#include <string.h>
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#include "libcpuid.h"
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#include "libcpuid_util.h"
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#include "asm-bits.h"
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#include "rdtsc.h"
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#ifdef _WIN32
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#include <windows.h>
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void sys_precise_clock(uint64_t *result)
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{
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double c, f;
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LARGE_INTEGER freq, counter;
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QueryPerformanceCounter(&counter);
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QueryPerformanceFrequency(&freq);
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c = (double) counter.QuadPart;
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f = (double) freq.QuadPart;
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*result = (uint64_t) ( c * 1000000.0 / f );
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}
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#else
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/* assuming Linux, Mac OS or other POSIX */
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#include <sys/time.h>
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void sys_precise_clock(uint64_t *result)
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{
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struct timeval tv;
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gettimeofday(&tv, NULL);
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*result = (uint64_t) tv.tv_sec * (uint64_t) 1000000 +
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(uint64_t) tv.tv_usec;
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}
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#endif /* _WIN32 */
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/* out = a - b */
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static void mark_t_subtract(struct cpu_mark_t* a, struct cpu_mark_t* b, struct cpu_mark_t *out)
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{
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out->tsc = a->tsc - b->tsc;
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out->sys_clock = a->sys_clock - b->sys_clock;
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}
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void cpu_tsc_mark(struct cpu_mark_t* mark)
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{
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cpu_rdtsc(&mark->tsc);
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sys_precise_clock(&mark->sys_clock);
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}
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void cpu_tsc_unmark(struct cpu_mark_t* mark)
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{
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struct cpu_mark_t temp;
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cpu_tsc_mark(&temp);
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mark_t_subtract(&temp, mark, mark);
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}
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int cpu_clock_by_mark(struct cpu_mark_t* mark)
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{
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uint64_t result;
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/* Check if some subtraction resulted in a negative number: */
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if ((mark->tsc >> 63) != 0 || (mark->sys_clock >> 63) != 0) return -1;
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/* Divide-by-zero check: */
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if (mark->sys_clock == 0) return -1;
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/* Check if the result fits in 32bits */
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result = mark->tsc / mark->sys_clock;
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if (result > (uint64_t) 0x7fffffff) return -1;
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return (int) result;
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}
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#ifdef _WIN32
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int cpu_clock_by_os(void)
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{
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HKEY key;
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DWORD result;
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DWORD size = 4;
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if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, TEXT("HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0"), 0, KEY_READ, &key) != ERROR_SUCCESS)
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return -1;
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if (RegQueryValueEx(key, TEXT("~MHz"), NULL, NULL, (LPBYTE) &result, (LPDWORD) &size) != ERROR_SUCCESS) {
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RegCloseKey(key);
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return -1;
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}
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RegCloseKey(key);
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return (int)result;
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}
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#else
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#ifdef __APPLE__
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#include <sys/types.h>
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#include <sys/sysctl.h>
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/* Assuming Mac OS X with hw.cpufrequency sysctl */
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int cpu_clock_by_os(void)
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{
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long long result = -1;
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size_t size = sizeof(result);
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if (sysctlbyname("hw.cpufrequency", &result, &size, NULL, 0))
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return -1;
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return (int) (result / (long long) 1000000);
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}
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#else
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/* Assuming Linux with /proc/cpuinfo */
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int cpu_clock_by_os(void)
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{
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FILE *f;
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char line[1024], *s;
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int result;
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f = fopen("/proc/cpuinfo", "rt");
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if (!f) return -1;
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while (fgets(line, sizeof(line), f)) {
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if (!strncmp(line, "cpu MHz", 7)) {
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s = strchr(line, ':');
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if (s && 1 == sscanf(s, ":%d.", &result)) {
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fclose(f);
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return result;
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}
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}
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}
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fclose(f);
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return -1;
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}
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#endif /* __APPLE__ */
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#endif /* _WIN32 */
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/* Emulate doing useful CPU intensive work */
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static int busy_loop(int amount)
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{
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int i, j, k, s = 0;
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static volatile int data[42] = {32, 12, -1, 5, 23, 0 };
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for (i = 0; i < amount; i++)
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for (j = 0; j < 65536; j++)
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for (k = 0; k < 42; k++)
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s += data[k];
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return s;
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}
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int busy_loop_delay(int milliseconds)
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{
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int cycles = 0, r = 0, first = 1;
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uint64_t a, b, c;
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sys_precise_clock(&a);
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while (1) {
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sys_precise_clock(&c);
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if ((c - a) / 1000 > milliseconds) return r;
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r += busy_loop(cycles);
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if (first) {
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first = 0;
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} else {
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if (c - b < 1000) cycles *= 2;
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if (c - b > 10000) cycles /= 2;
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}
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b = c;
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}
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}
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int cpu_clock_measure(int millis, int quad_check)
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{
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struct cpu_mark_t begin[4], end[4], temp, temp2;
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int results[4], cycles, n, k, i, j, bi, bj, mdiff, diff, _zero = 0;
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uint64_t tl;
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if (millis < 1) return -1;
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tl = millis * (uint64_t) 1000;
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if (quad_check)
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tl /= 4;
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n = quad_check ? 4 : 1;
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cycles = 1;
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for (k = 0; k < n; k++) {
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cpu_tsc_mark(&begin[k]);
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end[k] = begin[k];
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do {
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/* Run busy loop, and fool the compiler that we USE the garbishy
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value it calculates */
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_zero |= (1 & busy_loop(cycles));
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cpu_tsc_mark(&temp);
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mark_t_subtract(&temp, &end[k], &temp2);
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/* If busy loop is too short, increase it */
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if (temp2.sys_clock < tl / 8)
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cycles *= 2;
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end[k] = temp;
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} while (end[k].sys_clock - begin[k].sys_clock < tl);
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mark_t_subtract(&end[k], &begin[k], &temp);
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results[k] = cpu_clock_by_mark(&temp);
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}
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if (n == 1) return results[0];
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mdiff = 0x7fffffff;
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bi = bj = -1;
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for (i = 0; i < 4; i++) {
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for (j = i + 1; j < 4; j++) {
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diff = results[i] - results[j];
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if (diff < 0) diff = -diff;
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if (diff < mdiff) {
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mdiff = diff;
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bi = i;
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bj = j;
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}
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}
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}
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if (results[bi] == -1) return -1;
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return (results[bi] + results[bj] + _zero) / 2;
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}
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static void adjust_march_ic_multiplier(const struct cpu_id_t* id, int* numerator, int* denom)
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{
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/*
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* for cpu_clock_by_ic: we need to know how many clocks does a typical ADDPS instruction
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* take, when issued in rapid succesion without dependencies. The whole idea of
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* cpu_clock_by_ic was that this is easy to determine, at least it was back in 2010. Now
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* it's getting progressively more hairy, but here are the current measurements:
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*
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* 1. For CPUs with 64-bit SSE units, ADDPS issue rate is 0.5 IPC (one insn in 2 clocks)
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* 2. For CPUs with 128-bit SSE units, issue rate is exactly 1.0 IPC
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* 3. For Bulldozer and later, it is 1.4 IPC (we multiply by 5/7)
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* 4. For Skylake and later, it is 1.6 IPC (we multiply by 5/8)
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*/
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//
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if (id->sse_size < 128) {
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debugf(1, "SSE execution path is 64-bit\n");
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// on a CPU with half SSE unit length, SSE instructions execute at 0.5 IPC;
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// the resulting value must be multiplied by 2:
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*numerator = 2;
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} else {
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debugf(1, "SSE execution path is 128-bit\n");
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}
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//
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// Bulldozer or later: assume 1.4 IPC
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if (id->vendor == VENDOR_AMD && id->ext_family >= 21) {
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debugf(1, "cpu_clock_by_ic: Bulldozer (or later) detected, dividing result by 1.4\n");
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*numerator = 5;
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*denom = 7; // multiply by 5/7, to divide by 1.4
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}
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//
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// Skylake or later: assume 1.6 IPC
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if (id->vendor == VENDOR_INTEL && id->ext_model >= 94) {
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debugf(1, "cpu_clock_by_ic: Skylake (or later) detected, dividing result by 1.6\n");
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*numerator = 5;
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*denom = 8; // to divide by 1.6, multiply by 5/8
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}
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}
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int cpu_clock_by_ic(int millis, int runs)
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{
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int max_value = 0, cur_value, i, ri, cycles_inner, cycles_outer, c;
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struct cpu_id_t* id;
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uint64_t t0, t1, tl, hz;
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int multiplier_numerator = 1, multiplier_denom = 1;
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if (millis <= 0 || runs <= 0) return -2;
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id = get_cached_cpuid();
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// if there aren't SSE instructions - we can't run the test at all
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if (!id || !id->flags[CPU_FEATURE_SSE]) return -1;
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//
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adjust_march_ic_multiplier(id, &multiplier_numerator, &multiplier_denom);
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//
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tl = millis * 125; // (*1000 / 8)
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cycles_inner = 128;
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cycles_outer = 1;
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do {
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if (cycles_inner < 1000000000) cycles_inner *= 2;
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else cycles_outer *= 2;
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sys_precise_clock(&t0);
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for (i = 0; i < cycles_outer; i++)
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busy_sse_loop(cycles_inner);
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sys_precise_clock(&t1);
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} while (t1 - t0 < tl);
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debugf(2, "inner: %d, outer: %d\n", cycles_inner, cycles_outer);
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for (ri = 0; ri < runs; ri++) {
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sys_precise_clock(&t0);
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c = 0;
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do {
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c++;
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for (i = 0; i < cycles_outer; i++)
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busy_sse_loop(cycles_inner);
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sys_precise_clock(&t1);
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} while (t1 - t0 < tl * (uint64_t) 8);
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// cpu_Hz = cycles_inner * cycles_outer * 256 / (t1 - t0) * 1000000
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debugf(2, "c = %d, td = %d\n", c, (int) (t1 - t0));
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hz = ((uint64_t) cycles_inner * (uint64_t) 256 + 12) *
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(uint64_t) cycles_outer * (uint64_t) multiplier_numerator * (uint64_t) c * (uint64_t) 1000000
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/ ((t1 - t0) * (uint64_t) multiplier_denom);
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cur_value = (int) (hz / 1000000);
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if (cur_value > max_value) max_value = cur_value;
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}
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return max_value;
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}
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int cpu_clock(void)
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{
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int result;
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result = cpu_clock_by_os();
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if (result <= 0)
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result = cpu_clock_measure(200, 1);
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return result;
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}
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