SystemInformation: Fix counts of logical and physical cores

Issue: cmake/cmake#16594

SystemInformation.cxx

@@ -35,8 +35,13 @@
 #include "SystemInformation.hxx.in"
 #endif
 
+#include <algorithm>
+#include <bitset>
+#include <cassert>
 #include <fstream>
 #include <iostream>
+#include <limits>
+#include <set>
 #include <sstream>
 #include <string>
 #include <vector>
@@ -394,7 +399,6 @@ public:
     bool SupportsMP;
     bool HasMMXPlus;
     bool HasSSEMMX;
-    bool SupportsHyperthreading;
     unsigned int LogicalProcessorsPerPhysical;
     int APIC_ID;
     CPUPowerManagement PowerManagement;
@@ -463,10 +467,9 @@ protected:
   unsigned int NumberOfLogicalCPU;
   unsigned int NumberOfPhysicalCPU;
 
-  int CPUCount(); // For windows
-  unsigned char LogicalCPUPerPhysicalCPU();
+  void CPUCountWindows();    // For windows
   unsigned char GetAPICId(); // For windows
-  bool IsHyperThreadingSupported();
+  bool IsSMTSupported();
   static LongLong GetCyclesDifference(DELAY_FUNC, unsigned int); // For windows
 
   // For Linux and Cygwin, /proc/cpuinfo formats are slightly different
@@ -1542,7 +1545,7 @@ void SystemInformationImplementation::RunCPUCheck()
     RetrieveProcessorSerialNumber();
   }
 
-  this->CPUCount();
+  this->CPUCountWindows();
 
 #elif defined(__APPLE__)
   this->ParseSysCtl();
@@ -2090,16 +2093,10 @@ bool SystemInformationImplementation::RetrieveCPUFeatures()
 
   // Retrieve Intel specific extended features.
   if (this->ChipManufacturer == Intel) {
-    this->Features.ExtendedFeatures.SupportsHyperthreading =
-      ((cpuinfo[3] & 0x10000000) !=
-       0); // Intel specific: Hyperthreading --> Bit 28
-    this->Features.ExtendedFeatures.LogicalProcessorsPerPhysical =
-      (this->Features.ExtendedFeatures.SupportsHyperthreading)
-      ? ((cpuinfo[1] & 0x00FF0000) >> 16)
-      : 1;
-
-    if ((this->Features.ExtendedFeatures.SupportsHyperthreading) &&
-        (this->Features.HasAPIC)) {
+    bool SupportsSMT =
+      ((cpuinfo[3] & 0x10000000) != 0); // Intel specific: SMT --> Bit 28
+
+    if ((SupportsSMT) && (this->Features.HasAPIC)) {
       // Retrieve APIC information if there is one present.
       this->Features.ExtendedFeatures.APIC_ID =
         ((cpuinfo[1] & 0xFF000000) >> 24);
@@ -3401,7 +3398,7 @@ bool SystemInformationImplementation::RetreiveInformationFromCpuInfoFile()
   fclose(fd);
   buffer.resize(fileSize - 2);
   // Number of logical CPUs (combination of multiple processors, multi-core
-  // and hyperthreading)
+  // and SMT)
   size_t pos = buffer.find("processor\t");
   while (pos != buffer.npos) {
     this->NumberOfLogicalCPU++;
@@ -3409,30 +3406,24 @@ bool SystemInformationImplementation::RetreiveInformationFromCpuInfoFile()
   }
 
 #ifdef __linux
-  // Find the largest physical id.
-  int maxId = -1;
+  // Count sockets.
+  std::set<int> PhysicalIDs;
   std::string idc = this->ExtractValueFromCpuInfoFile(buffer, "physical id");
   while (this->CurrentPositionInFile != buffer.npos) {
     int id = atoi(idc.c_str());
-    if (id > maxId) {
-      maxId = id;
-    }
+    PhysicalIDs.insert(id);
     idc = this->ExtractValueFromCpuInfoFile(buffer, "physical id",
                                             this->CurrentPositionInFile + 1);
   }
+  uint64_t NumberOfSockets = PhysicalIDs.size();
+  NumberOfSockets = std::max(NumberOfSockets, (uint64_t)1);
   // Physical ids returned by Linux don't distinguish cores.
   // We want to record the total number of cores in this->NumberOfPhysicalCPU
   // (checking only the first proc)
-  std::string cores = this->ExtractValueFromCpuInfoFile(buffer, "cpu cores");
-  int numberOfCoresPerCPU = atoi(cores.c_str());
-  if (maxId > 0) {
-    this->NumberOfPhysicalCPU =
-      static_cast<unsigned int>(numberOfCoresPerCPU * (maxId + 1));
-  } else {
-    // Linux Sparc: get cpu count
-    this->NumberOfPhysicalCPU =
-      atoi(this->ExtractValueFromCpuInfoFile(buffer, "ncpus active").c_str());
-  }
+  std::string Cores = this->ExtractValueFromCpuInfoFile(buffer, "cpu cores");
+  int NumberOfCoresPerSocket = atoi(Cores.c_str());
+  NumberOfCoresPerSocket = std::max(NumberOfCoresPerSocket, 1);
+  this->NumberOfPhysicalCPU = NumberOfCoresPerSocket * NumberOfSockets;
 
 #else // __CYGWIN__
   // does not have "physical id" entries, neither "cpu cores"
@@ -3447,7 +3438,7 @@ bool SystemInformationImplementation::RetreiveInformationFromCpuInfoFile()
   if (this->NumberOfPhysicalCPU <= 0) {
     this->NumberOfPhysicalCPU = 1;
   }
-  // LogicalProcessorsPerPhysical>1 => hyperthreading.
+  // LogicalProcessorsPerPhysical>1 => SMT.
   this->Features.ExtendedFeatures.LogicalProcessorsPerPhysical =
     this->NumberOfLogicalCPU / this->NumberOfPhysicalCPU;
 
@@ -4322,68 +4313,10 @@ void SystemInformationImplementation::DelayOverhead(unsigned int uiMS)
   (void)uiMS;
 }
 
-/** Return the number of logical CPU per physical CPUs Works only for windows
- */
-unsigned char SystemInformationImplementation::LogicalCPUPerPhysicalCPU(void)
-{
-#ifdef __APPLE__
-  size_t len = 4;
-  int cores_per_package = 0;
-  int err = sysctlbyname("machdep.cpu.cores_per_package", &cores_per_package,
-                         &len, NULL, 0);
-  if (err != 0) {
-    return 1; // That name was not found, default to 1
-  }
-  return static_cast<unsigned char>(cores_per_package);
-#else
-  int Regs[4] = { 0, 0, 0, 0 };
-#if USE_CPUID
-  if (!this->IsHyperThreadingSupported()) {
-    return static_cast<unsigned char>(1); // HT not supported
-  }
-  call_cpuid(1, Regs);
-#endif
-  return static_cast<unsigned char>((Regs[1] & NUM_LOGICAL_BITS) >> 16);
-#endif
-}
-
 /** Works only for windows */
-bool SystemInformationImplementation::IsHyperThreadingSupported()
+bool SystemInformationImplementation::IsSMTSupported()
 {
-  if (this->Features.ExtendedFeatures.SupportsHyperthreading) {
-    return true;
-  }
-
-#if USE_CPUID
-  int Regs[4] = { 0, 0, 0, 0 }, VendorId[4] = { 0, 0, 0, 0 };
-  // Get vendor id string
-  if (!call_cpuid(0, VendorId)) {
-    return false;
-  }
-  // eax contains family processor type
-  // edx has info about the availability of hyper-Threading
-  if (!call_cpuid(1, Regs)) {
-    return false;
-  }
-
-  if (((Regs[0] & FAMILY_ID) == PENTIUM4_ID) || (Regs[0] & EXT_FAMILY_ID)) {
-    if (VendorId[1] == 0x756e6547) // 'uneG'
-    {
-      if (VendorId[3] == 0x49656e69) // 'Ieni'
-      {
-        if (VendorId[2] == 0x6c65746e) // 'letn'
-        {
-          // Genuine Intel with hyper-Threading technology
-          this->Features.ExtendedFeatures.SupportsHyperthreading =
-            ((Regs[3] & HT_BIT) != 0);
-          return this->Features.ExtendedFeatures.SupportsHyperthreading;
-        }
-      }
-    }
-  }
-#endif
-
-  return 0; // Not genuine Intel processor
+  return this->Features.ExtendedFeatures.LogicalProcessorsPerPhysical > 1;
 }
 
 /** Return the APIC Id. Works only for windows. */
@@ -4392,7 +4325,7 @@ unsigned char SystemInformationImplementation::GetAPICId()
   int Regs[4] = { 0, 0, 0, 0 };
 
 #if USE_CPUID
-  if (!this->IsHyperThreadingSupported()) {
+  if (!this->IsSMTSupported()) {
     return static_cast<unsigned char>(-1); // HT not supported
   }                                        // Logical processor = 1
   call_cpuid(1, Regs);
@@ -4402,102 +4335,46 @@ unsigned char SystemInformationImplementation::GetAPICId()
 }
 
 /** Count the number of CPUs. Works only on windows. */
-int SystemInformationImplementation::CPUCount()
+void SystemInformationImplementation::CPUCountWindows()
 {
 #if defined(_WIN32)
-  unsigned char StatusFlag = 0;
-  SYSTEM_INFO info;
-
+  std::vector<SYSTEM_LOGICAL_PROCESSOR_INFORMATION> ProcInfo;
   this->NumberOfPhysicalCPU = 0;
   this->NumberOfLogicalCPU = 0;
-  info.dwNumberOfProcessors = 0;
-  GetSystemInfo(&info);
-
-  // Number of physical processors in a non-Intel system
-  // or in a 32-bit Intel system with Hyper-Threading technology disabled
-  this->NumberOfPhysicalCPU = (unsigned char)info.dwNumberOfProcessors;
-
-  if (this->IsHyperThreadingSupported()) {
-    unsigned char HT_Enabled = 0;
-    this->NumberOfLogicalCPU = this->LogicalCPUPerPhysicalCPU();
-    if (this->NumberOfLogicalCPU >=
-        1) // >1 Doesn't mean HT is enabled in the BIOS
-    {
-      HANDLE hCurrentProcessHandle;
-#ifndef _WIN64
-#define DWORD_PTR DWORD
-#endif
-      DWORD_PTR dwProcessAffinity;
-      DWORD_PTR dwSystemAffinity;
-      DWORD dwAffinityMask;
-
-      // Calculate the appropriate  shifts and mask based on the
-      // number of logical processors.
-      unsigned int i = 1;
-      unsigned char PHY_ID_MASK = 0xFF;
-      // unsigned char PHY_ID_SHIFT = 0;
-
-      while (i < this->NumberOfLogicalCPU) {
-        i *= 2;
-        PHY_ID_MASK <<= 1;
-        // PHY_ID_SHIFT++;
-      }
 
-      hCurrentProcessHandle = GetCurrentProcess();
-      GetProcessAffinityMask(hCurrentProcessHandle, &dwProcessAffinity,
-                             &dwSystemAffinity);
-
-      // Check if available process affinity mask is equal to the
-      // available system affinity mask
-      if (dwProcessAffinity != dwSystemAffinity) {
-        StatusFlag = HT_CANNOT_DETECT;
-        this->NumberOfPhysicalCPU = (unsigned char)-1;
-        return StatusFlag;
-      }
-
-      dwAffinityMask = 1;
-      while (dwAffinityMask != 0 && dwAffinityMask <= dwProcessAffinity) {
-        // Check if this CPU is available
-        if (dwAffinityMask & dwProcessAffinity) {
-          if (SetProcessAffinityMask(hCurrentProcessHandle, dwAffinityMask)) {
-            unsigned char APIC_ID, LOG_ID;
-            Sleep(0); // Give OS time to switch CPU
-
-            APIC_ID = GetAPICId();
-            LOG_ID = APIC_ID & ~PHY_ID_MASK;
-
-            if (LOG_ID != 0) {
-              HT_Enabled = 1;
-            }
-          }
-        }
-        dwAffinityMask = dwAffinityMask << 1;
-      }
-      // Reset the processor affinity
-      SetProcessAffinityMask(hCurrentProcessHandle, dwProcessAffinity);
+  {
+    DWORD Length = 0;
+    DWORD rc = GetLogicalProcessorInformation(NULL, &Length);
+    assert(FALSE == rc);
+    (void)rc; // Silence unused variable warning in Borland C++ 5.81
+    assert(GetLastError() == ERROR_INSUFFICIENT_BUFFER);
+    ProcInfo.resize(Length / sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION));
+    rc = GetLogicalProcessorInformation(&ProcInfo[0], &Length);
+    assert(rc != FALSE);
+    (void)rc; // Silence unused variable warning in Borland C++ 5.81
+  }
+
+  typedef std::vector<SYSTEM_LOGICAL_PROCESSOR_INFORMATION>::iterator
+    pinfoIt_t;
+  for (pinfoIt_t it = ProcInfo.begin(); it != ProcInfo.end(); ++it) {
+    SYSTEM_LOGICAL_PROCESSOR_INFORMATION PInfo = *it;
+    if (PInfo.Relationship != RelationProcessorCore) {
+      continue;
+    }
 
-      if (this->NumberOfLogicalCPU ==
-          1) // Normal P4 : HT is disabled in hardware
-      {
-        StatusFlag = HT_DISABLED;
-      } else {
-        if (HT_Enabled) {
-          // Total physical processors in a Hyper-Threading enabled system.
-          this->NumberOfPhysicalCPU /= (this->NumberOfLogicalCPU);
-          StatusFlag = HT_ENABLED;
-        } else {
-          StatusFlag = HT_SUPPORTED_NOT_ENABLED;
-        }
-      }
+    std::bitset<std::numeric_limits<ULONG_PTR>::digits> ProcMask(
+      (unsigned long long)PInfo.ProcessorMask);
+    unsigned int count = (unsigned int)ProcMask.count();
+    if (count == 0) { // I think this should never happen, but just to be safe.
+      continue;
     }
-  } else {
-    // Processors do not have Hyper-Threading technology
-    StatusFlag = HT_NOT_CAPABLE;
-    this->NumberOfLogicalCPU = 1;
+    this->NumberOfPhysicalCPU++;
+    this->NumberOfLogicalCPU += (unsigned int)count;
+    this->Features.ExtendedFeatures.LogicalProcessorsPerPhysical = count;
   }
-  return StatusFlag;
+  this->NumberOfPhysicalCPU = std::max(1u, this->NumberOfPhysicalCPU);
+  this->NumberOfLogicalCPU = std::max(1u, this->NumberOfLogicalCPU);
 #else
-  return 0;
 #endif
 }
 
@@ -4559,8 +4436,14 @@ bool SystemInformationImplementation::ParseSysCtl()
   sysctlbyname("hw.physicalcpu", &this->NumberOfPhysicalCPU, &len, NULL, 0);
   len = sizeof(this->NumberOfLogicalCPU);
   sysctlbyname("hw.logicalcpu", &this->NumberOfLogicalCPU, &len, NULL, 0);
+
+  int cores_per_package = 0;
+  len = sizeof(cores_per_package);
+  err = sysctlbyname("machdep.cpu.cores_per_package", &cores_per_package, &len,
+                     NULL, 0);
+  // That name was not found, default to 1
   this->Features.ExtendedFeatures.LogicalProcessorsPerPhysical =
-    this->LogicalCPUPerPhysicalCPU();
+    err != 0 ? 1 : static_cast<unsigned char>(cores_per_package);
 
   len = sizeof(value);
   sysctlbyname("hw.cpufrequency", &value, &len, NULL, 0);

SystemInformation.hxx.in

@@ -67,7 +67,7 @@ public:
 
   bool Is64Bits();
 
-  unsigned int GetNumberOfLogicalCPU(); // per physical cpu
+  unsigned int GetNumberOfLogicalCPU();
   unsigned int GetNumberOfPhysicalCPU();
 
   bool DoesCPUSupportCPUID();