Use sysctl instead of the cpuid method to detect the physical core count

smc.c

@@ -206,41 +206,10 @@ unsigned long getCoreArgCount(const char *arg) {
 }
 
 int getPhysicalCoreCount() {
- // https://stackoverflow.com/a/150971
- int mib[4];
- int numCPU;
- size_t len = sizeof(numCPU);
-
- /* set the mib for hw.ncpu */
- mib[0] = CTL_HW;
- mib[1] = HW_NCPU; // alternatively, try HW_NCPU;
-
- /* get the number of CPUs from the system */
- sysctl(mib, 2, &numCPU, &len, NULL, 0);
-
- if (numCPU < 1) {
- mib[1] = HW_NCPU;
- sysctl(mib, 2, &numCPU, &len, NULL, 0);
- if (numCPU < 1)
- numCPU = 1;
- }
-
- // https://stackoverflow.com/a/29761237
- uint32_t registers[4];
- __asm__ __volatile__("cpuid "
- : "=a"(registers[0]),
- "=b"(registers[1]),
- "=c"(registers[2]),
- "=d"(registers[3])
- : "a"(1), "c"(0));
-
- unsigned cpuFeatureSet = registers[3];
- bool hyperthreading = cpuFeatureSet & (1 << 28);
-
- if (hyperthreading)
- return numCPU / 2;
- else
- return numCPU;
+ int coreCount;
+ size_t len = sizeof(coreCount);
+ sysctlbyname("hw.physicalcpu_max", &coreCount, &len, NULL, 0);
+ return coreCount;
 }
 
 void getCoreNumbers(char *arg, unsigned long *cores, char *errorMsg) {