detect AVX-512 FMA count (#125)

* add Ice Lake Server and Sapphire Rapids models

The information contained in this commit was obtained from
"Intel® Architecture Instruction Set Extensions and Future Features Programming Reference" document 319433-040 from
https://software.intel.com/content/www/us/en/develop/download/intel-architecture-instruction-set-extensions-programming-reference.html

Signed-off-by: Jeff Hammond <[email protected]>

* Tiger Lake; Ice Lake NNP-I; SPR string

Signed-off-by: Hammond, Jeff R <[email protected]>

* second FMA features - incomplete and wrong

Signed-off-by: Hammond, Jeff R <[email protected]>

* oops: use T/F not 2/1

Signed-off-by: Jeff Hammond <[email protected]>

* implement SKX lookup

Signed-off-by: Hammond, Jeff R <[email protected]>

* add Intel copyright

* cleanup AVX512 second FMA code

1) remove debug stuff
2) remove ICX - will add details when available

Signed-off-by: Hammond, Jeff R <[email protected]>

* fix CPX detection

Signed-off-by: Hammond, Jeff R <[email protected]>

* remove elses

Signed-off-by: Hammond, Jeff R <[email protected]>

* remove curly braces from single-line conditional bodies

Signed-off-by: Hammond, Jeff R <[email protected]>

* apply clang-format

Signed-off-by: Hammond, Jeff R <[email protected]>

Fixes #120

Author: Jeff Hammond

include/cpuinfo_x86.h

@@ -69,10 +69,11 @@ typedef struct {
   int avx512bitalg : 1;
   int avx512vpopcntdq : 1;
   int avx512_4vnniw : 1;
+  int avx512_4vbmi2 : 1;
+  int avx512_second_fma : 1;
   int avx512_4fmaps : 1;
   int avx512_bf16 : 1;
   int avx512_vp2intersect : 1;
-
   int amx_bf16 : 1;
   int amx_tile : 1;
   int amx_int8 : 1;
@@ -194,6 +195,8 @@ typedef enum {
   X86_AVX512BITALG,
   X86_AVX512VPOPCNTDQ,
   X86_AVX512_4VNNIW,
+  X86_AVX512_4VBMI2,
+  X86_AVX512_SECOND_FMA,
   X86_AVX512_4FMAPS,
   X86_AVX512_BF16,
   X86_AVX512_VP2INTERSECT,

src/cpuinfo_x86.c

@@ -14,12 +14,13 @@
 // limitations under the License.
 
 #include "cpuinfo_x86.h"
-#include "internal/bit_utils.h"
-#include "internal/cpuid_x86.h"
 
 #include <stdbool.h>
 #include <string.h>
 
+#include "internal/bit_utils.h"
+#include "internal/cpuid_x86.h"
+
 #if !defined(CPU_FEATURES_ARCH_X86)
 #error "Cannot compile cpuinfo_x86 on a non x86 platform."
 #endif
@@ -125,6 +126,35 @@ static bool HasTmmOsXSave(uint32_t xcr0_eax) {
                                MASK_ZMM16_31 | MASK_XTILECFG | MASK_XTILEDATA);
 }
 
+static bool HasSecondFMA(uint32_t model) {
+  // Skylake server
+  if (model == 0x55) {
+    char proc_name[49] = {0};
+    FillX86BrandString(proc_name);
+    // detect Xeon
+    if (proc_name[9] == 'X') {
+      // detect Silver or Bronze
+      if (proc_name[17] == 'S' || proc_name[17] == 'B') return false;
+      // detect Gold 5_20 and below, except for Gold 53__
+      if (proc_name[17] == 'G' && proc_name[22] == '5')
+        return ((proc_name[23] == '3') ||
+                (proc_name[24] == '2' && proc_name[25] == '2'));
+      // detect Xeon W 210x
+      if (proc_name[17] == 'W' && proc_name[21] == '0') return false;
+      // detect Xeon D 2xxx
+      if (proc_name[17] == 'D' && proc_name[19] == '2' && proc_name[20] == '1')
+        return false;
+    }
+    return true;
+  }
+  // Cannon Lake client
+  if (model == 0x66) return false;
+  // Ice Lake client
+  if (model == 0x7d || model == 0x7e) return false;
+  // This is the right default...
+  return true;
+}
+
 static void SetVendor(const Leaf leaf, char* const vendor) {
   *(uint32_t*)(vendor) = leaf.ebx;
   *(uint32_t*)(vendor + 4) = leaf.edx;
@@ -1059,7 +1089,8 @@ typedef struct {
 } OsSupport;
 
 // Reference https://en.wikipedia.org/wiki/CPUID.
-static void ParseCpuId(const uint32_t max_cpuid_leaf, X86Info* info, OsSupport* os_support) {
+static void ParseCpuId(const uint32_t max_cpuid_leaf, X86Info* info,
+                       OsSupport* os_support) {
   const Leaf leaf_1 = SafeCpuId(max_cpuid_leaf, 1);
   const Leaf leaf_7 = SafeCpuId(max_cpuid_leaf, 7);
   const Leaf leaf_7_1 = SafeCpuIdEx(max_cpuid_leaf, 7, 1);
@@ -1141,6 +1172,8 @@ static void ParseCpuId(const uint32_t max_cpuid_leaf, X86Info* info, OsSupport*
     features->avx512bitalg = IsBitSet(leaf_7.ecx, 12);
     features->avx512vpopcntdq = IsBitSet(leaf_7.ecx, 14);
     features->avx512_4vnniw = IsBitSet(leaf_7.edx, 2);
+    features->avx512_4vbmi2 = IsBitSet(leaf_7.edx, 3);
+    features->avx512_second_fma = HasSecondFMA(info->model);
     features->avx512_4fmaps = IsBitSet(leaf_7.edx, 3);
     features->avx512_bf16 = IsBitSet(leaf_7_1.eax, 5);
     features->avx512_vp2intersect = IsBitSet(leaf_7.edx, 8);
@@ -1153,7 +1186,8 @@ static void ParseCpuId(const uint32_t max_cpuid_leaf, X86Info* info, OsSupport*
   }
 }
 
-// Reference https://en.wikipedia.org/wiki/CPUID#EAX=80000000h:_Get_Highest_Extended_Function_Implemented.
+// Reference
+// https://en.wikipedia.org/wiki/CPUID#EAX=80000000h:_Get_Highest_Extended_Function_Implemented.
 static void ParseExtraAMDCpuId(X86Info* info, OsSupport os_support) {
   const Leaf leaf_80000000 = CpuId(0x80000000);
   const uint32_t max_extended_cpuid_leaf = leaf_80000000.eax;
@@ -1265,11 +1299,11 @@ X86Microarchitecture GetX86Microarchitecture(const X86Info* info) {
       case CPUID(0x06, 0x66):
         // https://en.wikipedia.org/wiki/Cannon_Lake_(microarchitecture)
         return INTEL_CNL;
-      case CPUID(0x06, 0x7D): // client
-      case CPUID(0x06, 0x7E): // client
-      case CPUID(0x06, 0x9D): // NNP-I
-      case CPUID(0x06, 0x6A): // server
-      case CPUID(0x06, 0x6C): // server
+      case CPUID(0x06, 0x7D):  // client
+      case CPUID(0x06, 0x7E):  // client
+      case CPUID(0x06, 0x9D):  // NNP-I
+      case CPUID(0x06, 0x6A):  // server
+      case CPUID(0x06, 0x6C):  // server
         // https://en.wikipedia.org/wiki/Ice_Lake_(microprocessor)
         return INTEL_ICL;
       case CPUID(0x06, 0x8C):
@@ -1281,10 +1315,14 @@ X86Microarchitecture GetX86Microarchitecture(const X86Info* info) {
         return INTEL_SPR;
       case CPUID(0x06, 0x8E):
         switch (info->stepping) {
-          case 9:  return INTEL_KBL;  // https://en.wikipedia.org/wiki/Kaby_Lake
-          case 10: return INTEL_CFL;  // https://en.wikipedia.org/wiki/Coffee_Lake
-          case 11: return INTEL_WHL;  // https://en.wikipedia.org/wiki/Whiskey_Lake_(microarchitecture)
-          default: return X86_UNKNOWN;
+          case 9:
+            return INTEL_KBL;  // https://en.wikipedia.org/wiki/Kaby_Lake
+          case 10:
+            return INTEL_CFL;  // https://en.wikipedia.org/wiki/Coffee_Lake
+          case 11:
+            return INTEL_WHL;  // https://en.wikipedia.org/wiki/Whiskey_Lake_(microarchitecture)
+          default:
+            return X86_UNKNOWN;
         }
       case CPUID(0x06, 0x9E):
         if (info->stepping > 9) {
@@ -1427,6 +1465,10 @@ int GetX86FeaturesEnumValue(const X86Features* features,
       return features->avx512vpopcntdq;
     case X86_AVX512_4VNNIW:
       return features->avx512_4vnniw;
+    case X86_AVX512_4VBMI2:
+      return features->avx512_4vbmi2;
+    case X86_AVX512_SECOND_FMA:
+      return features->avx512_second_fma;
     case X86_AVX512_4FMAPS:
       return features->avx512_4fmaps;
     case X86_AVX512_BF16:
@@ -1551,6 +1593,10 @@ const char* GetX86FeaturesEnumName(X86FeaturesEnum value) {
       return "avx512vpopcntdq";
     case X86_AVX512_4VNNIW:
       return "avx512_4vnniw";
+    case X86_AVX512_4VBMI2:
+      return "avx512_4vbmi2";
+    case X86_AVX512_SECOND_FMA:
+      return "avx512_second_fma";
     case X86_AVX512_4FMAPS:
       return "avx512_4fmaps";
     case X86_AVX512_BF16: