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/*
util.h - utility functions
Copyright (C) 2023, Yann Collet
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#if defined (__cplusplus)
extern "C" {
#endif
/*-****************************************
* Dependencies
******************************************/
#include "util.h" /* note : ensure that platform.h is included first ! */
/*-****************************************
* count the number of cores
******************************************/
#if defined(_WIN32)
#include <windows.h>
int UTIL_countCores(void)
{
static int numCores = 0;
if (numCores != 0) return numCores;
{ SYSTEM_INFO sysinfo;
GetSystemInfo(&sysinfo);
numCores = sysinfo.dwNumberOfProcessors;
}
if (numCores == 0) {
/* Unexpected result, fall back on 1 */
return numCores = 1;
}
return numCores;
}
#elif defined(__APPLE__)
#include <sys/sysctl.h>
/* Use apple-provided syscall
* see: man 3 sysctl */
int UTIL_countCores(void)
{
static S32 numCores = 0; /* apple specifies int32_t */
if (numCores != 0) return (int)numCores;
{ size_t size = sizeof(S32);
int const ret = sysctlbyname("hw.logicalcpu", &numCores, &size, NULL, 0);
if (ret != 0) {
/* error: fall back on 1 */
numCores = 1;
}
}
return (int)numCores;
}
#elif defined(__linux__)
int UTIL_countCores(void)
{
static int numCores = 0;
if (numCores != 0) return numCores;
numCores = (int)sysconf(_SC_NPROCESSORS_ONLN);
if (numCores == -1) {
/* value not queryable, fall back on 1 */
return numCores = 1;
}
return numCores;
}
#elif defined(__FreeBSD__)
#include <stdio.h> /* perror */
#include <errno.h>
#include <sys/param.h>
#include <sys/sysctl.h>
/* Use physical core sysctl when available
* see: man 4 smp, man 3 sysctl */
int UTIL_countCores(void)
{
static int numCores = 0; /* freebsd sysctl is native int sized */
if (numCores != 0) return numCores;
#if __FreeBSD_version >= 1300008
{ size_t size = sizeof(numCores);
int ret = sysctlbyname("kern.smp.cores", &numCores, &size, NULL, 0);
if (ret == 0) {
int perCore = 1;
ret = sysctlbyname("kern.smp.threads_per_core", &perCore, &size, NULL, 0);
/* default to physical cores if logical cannot be read */
if (ret != 0) /* error */
return numCores;
numCores *= perCore;
return numCores;
}
if (errno != ENOENT) {
perror("lz4: can't get number of cpus");
exit(1);
}
/* sysctl not present, fall through to older sysconf method */
}
#endif
numCores = (int)sysconf(_SC_NPROCESSORS_ONLN);
if (numCores == -1) {
/* value not queryable, fall back on 1 */
numCores = 1;
}
return numCores;
}
#elif defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) || defined(__CYGWIN__)
/* Use POSIX sysconf
* see: man 3 sysconf */
int UTIL_countCores(void)
{
static int numCores = 0;
if (numCores != 0) return numCores;
numCores = (int)sysconf(_SC_NPROCESSORS_ONLN);
if (numCores == -1) {
/* value not queryable, fall back on 1 */
numCores = 1;
}
return numCores;
}
#else
int UTIL_countCores(void)
{
/* no clue */
return 1;
}
#endif
#if defined (__cplusplus)
}
#endif
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