ClickHouse/libs/libcpuid/include/cpuid/rdtsc.c

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