From 7053d97d2d627c1f2bbd019953748b09af99c1e2 Mon Sep 17 00:00:00 2001
From: Martin Quinson <martin.quinson@loria.fr>
Date: Wed, 18 Jul 2018 22:32:44 +0200
Subject: [PATCH] s/xbt_os_get_numcores()/std::thread::hardware_concurrency()/

---
 include/xbt/xbt_os_thread.h |  2 --
 src/simix/smx_context.cpp   | 16 ++++++++--------
 src/xbt/xbt_os_thread.c     | 25 -------------------------
 3 files changed, 8 insertions(+), 35 deletions(-)

diff --git a/include/xbt/xbt_os_thread.h b/include/xbt/xbt_os_thread.h
index e1591c7f97..d555995c1a 100644
--- a/include/xbt/xbt_os_thread.h
+++ b/include/xbt/xbt_os_thread.h
@@ -24,8 +24,6 @@ SG_BEGIN_DECL()
  *  @{
  */
 
-XBT_PUBLIC int xbt_os_get_numcores(void);
-
 /** @brief Thread data type (opaque structure) */
 typedef struct xbt_os_thread_ *xbt_os_thread_t;
 XBT_PUBLIC xbt_os_thread_t xbt_os_thread_create(const char* name, pvoid_f_pvoid_t start_routine, void* param,
diff --git a/src/simix/smx_context.cpp b/src/simix/smx_context.cpp
index 4fb8c473ab..5dbbfb2900 100644
--- a/src/simix/smx_context.cpp
+++ b/src/simix/smx_context.cpp
@@ -5,12 +5,6 @@
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
-#include <cerrno>
-#include <cstring>
-
-#include <utility>
-#include <string>
-
 #include <xbt/config.hpp>
 #include <xbt/log.h>
 #include <xbt/range.hpp>
@@ -23,6 +17,12 @@
 #include "xbt/log.h"
 #include "xbt/xbt_os_thread.h"
 
+#include <cerrno>
+#include <cstring>
+#include <string>
+#include <thread>
+#include <utility>
+
 #ifdef _WIN32
 #include <windows.h>
 #include <malloc.h>
@@ -259,8 +259,8 @@ int SIMIX_context_get_nthreads() {
  */
 void SIMIX_context_set_nthreads(int nb_threads) {
   if (nb_threads<=0) {
-     nb_threads = xbt_os_get_numcores();
-     XBT_INFO("Auto-setting contexts/nthreads to %d",nb_threads);
+    nb_threads = std::thread::hardware_concurrency();
+    XBT_INFO("Auto-setting contexts/nthreads to %d", nb_threads);
   }
 #if !HAVE_THREAD_CONTEXTS
   xbt_assert(nb_threads == 1, "Parallel runs are impossible when the pthreads are missing.");
diff --git a/src/xbt/xbt_os_thread.c b/src/xbt/xbt_os_thread.c
index 79242cdf5a..d4515ad27a 100644
--- a/src/xbt/xbt_os_thread.c
+++ b/src/xbt/xbt_os_thread.c
@@ -366,31 +366,6 @@ void xbt_os_sem_destroy(xbt_os_sem_t sem)
   xbt_free(sem);
 }
 
-/** @brief Returns the amount of cores on the current host */
-int xbt_os_get_numcores(void) {
-#ifdef WIN32
-    SYSTEM_INFO sysinfo;
-    GetSystemInfo(&sysinfo);
-    return sysinfo.dwNumberOfProcessors;
-#elif defined(__APPLE__) && defined(__MACH__)
-    int nm[2];
-    size_t len = 4;
-    uint32_t count;
-
-    nm[0] = CTL_HW; nm[1] = HW_AVAILCPU;
-    sysctl(nm, 2, &count, &len, NULL, 0);
-
-    if(count < 1) {
-        nm[1] = HW_NCPU;
-        sysctl(nm, 2, &count, &len, NULL, 0);
-        if(count < 1) { count = 1; }
-    }
-    return count;
-#else
-    return sysconf(_SC_NPROCESSORS_ONLN);
-#endif
-}
-
 void xbt_os_thread_set_extra_data(void *data)
 {
   xbt_os_thread_self()->extra_data = data;
-- 
2.20.1