Documentation ¶
Overview ¶
Package cpuid provides information about the CPU running the current program.
CPU features are detected on startup, and kept for fast access through the life of the application. Currently x86 / x64 (AMD64) as well as arm64 is supported.
You can access the CPU information by accessing the shared CPU variable of the cpuid library.
Package home: https://github.com/klauspost/cpuid
Example ¶
// Print basic CPU information: fmt.Println("Name:", CPU.BrandName) fmt.Println("PhysicalCores:", CPU.PhysicalCores) fmt.Println("ThreadsPerCore:", CPU.ThreadsPerCore) fmt.Println("LogicalCores:", CPU.LogicalCores) fmt.Println("Family", CPU.Family, "Model:", CPU.Model) fmt.Println("Features:", CPU.Features) fmt.Println("Cacheline bytes:", CPU.CacheLine) // Test if we have a specific feature: if CPU.SSE() { fmt.Println("We have Streaming SIMD Extensions") }
Output:
Index ¶
- Constants
- func Detect()
- type ArmFlags
- type CPUInfo
- func (c CPUInfo) ADX() bool
- func (c CPUInfo) AMD() bool
- func (c CPUInfo) AVX() bool
- func (c CPUInfo) AVX2() bool
- func (c CPUInfo) AVX512BF16() bool
- func (c CPUInfo) AVX512BITALG() bool
- func (c CPUInfo) AVX512BW() bool
- func (c CPUInfo) AVX512CD() bool
- func (c CPUInfo) AVX512DQ() bool
- func (c CPUInfo) AVX512ER() bool
- func (c CPUInfo) AVX512F() bool
- func (c CPUInfo) AVX512IFMA() bool
- func (c CPUInfo) AVX512PF() bool
- func (c CPUInfo) AVX512VBMI() bool
- func (c CPUInfo) AVX512VBMI2() bool
- func (c CPUInfo) AVX512VL() bool
- func (c CPUInfo) AVX512VNNI() bool
- func (c CPUInfo) AVX512VP2INTERSECT() bool
- func (c CPUInfo) AVX512VPOPCNTDQ() bool
- func (c CPUInfo) AesNi() bool
- func (c CPUInfo) Amd3dnow() bool
- func (c CPUInfo) Amd3dnowExt() bool
- func (c CPUInfo) ArmAES() bool
- func (c CPUInfo) ArmASIMD() bool
- func (c CPUInfo) ArmASIMDDP() bool
- func (c CPUInfo) ArmASIMDHP() bool
- func (c CPUInfo) ArmASIMDRDM() bool
- func (c CPUInfo) ArmATOMICS() bool
- func (c CPUInfo) ArmCRC32() bool
- func (c CPUInfo) ArmDCPOP() bool
- func (c CPUInfo) ArmEVTSTRM() bool
- func (c CPUInfo) ArmFCMA() bool
- func (c CPUInfo) ArmFP() bool
- func (c CPUInfo) ArmFPHP() bool
- func (c CPUInfo) ArmGPA() bool
- func (c CPUInfo) ArmJSCVT() bool
- func (c CPUInfo) ArmLRCPC() bool
- func (c CPUInfo) ArmPMULL() bool
- func (c CPUInfo) ArmSHA1() bool
- func (c CPUInfo) ArmSHA2() bool
- func (c CPUInfo) ArmSHA3() bool
- func (c CPUInfo) ArmSHA512() bool
- func (c CPUInfo) ArmSM3() bool
- func (c CPUInfo) ArmSM4() bool
- func (c CPUInfo) ArmSVE() bool
- func (c CPUInfo) Atom() bool
- func (c CPUInfo) BMI1() bool
- func (c CPUInfo) BMI2() bool
- func (c CPUInfo) CX16() bool
- func (c CPUInfo) Clmul() bool
- func (c CPUInfo) Cmov() bool
- func (c CPUInfo) ERMS() bool
- func (c CPUInfo) F16C() bool
- func (c CPUInfo) FMA3() bool
- func (c CPUInfo) FMA4() bool
- func (c CPUInfo) GFNI() bool
- func (c CPUInfo) HLE() bool
- func (c CPUInfo) HTT() bool
- func (c CPUInfo) Hygon() bool
- func (c CPUInfo) Ia32TscAux() uint32
- func (c CPUInfo) Intel() bool
- func (c CPUInfo) LogicalCPU() int
- func (c CPUInfo) Lzcnt() bool
- func (c CPUInfo) MMX() bool
- func (c CPUInfo) MMXExt() bool
- func (c CPUInfo) MPX() bool
- func (c CPUInfo) NSC() bool
- func (c CPUInfo) NX() bool
- func (c CPUInfo) Popcnt() bool
- func (c CPUInfo) RDTSCP() bool
- func (c CPUInfo) RTCounter() uint64
- func (c CPUInfo) RTM() bool
- func (c CPUInfo) Rdrand() bool
- func (c CPUInfo) Rdseed() bool
- func (c CPUInfo) SHA() bool
- func (c CPUInfo) SSE() bool
- func (c CPUInfo) SSE2() bool
- func (c CPUInfo) SSE2Slow() bool
- func (c CPUInfo) SSE3() bool
- func (c CPUInfo) SSE3Slow() bool
- func (c CPUInfo) SSE4() bool
- func (c CPUInfo) SSE42() bool
- func (c CPUInfo) SSE4A() bool
- func (c CPUInfo) SSSE3() bool
- func (c CPUInfo) TBM() bool
- func (c CPUInfo) TSX() bool
- func (c CPUInfo) Transmeta() bool
- func (c CPUInfo) VAES() bool
- func (c CPUInfo) VIA() bool
- func (c CPUInfo) VM() bool
- func (c CPUInfo) VMX() bool
- func (c CPUInfo) VPCLMULQDQ() bool
- func (c CPUInfo) XOP() bool
- type Flags
- type SGXEPCSection
- type SGXSupport
- type Vendor
Examples ¶
Constants ¶
const ( CMOV = 1 << iota // i686 CMOV NX // NX (No-Execute) bit AMD3DNOW // AMD 3DNOW AMD3DNOWEXT // AMD 3DNowExt MMX // standard MMX MMXEXT // SSE integer functions or AMD MMX ext SSE // SSE functions SSE2 // P4 SSE functions SSE3 // Prescott SSE3 functions SSSE3 // Conroe SSSE3 functions SSE4 // Penryn SSE4.1 functions SSE4A // AMD Barcelona microarchitecture SSE4a instructions SSE42 // Nehalem SSE4.2 functions AVX // AVX functions AVX2 // AVX2 functions FMA3 // Intel FMA 3 FMA4 // Bulldozer FMA4 functions XOP // Bulldozer XOP functions F16C // Half-precision floating-point conversion BMI1 // Bit Manipulation Instruction Set 1 BMI2 // Bit Manipulation Instruction Set 2 TBM // AMD Trailing Bit Manipulation LZCNT // LZCNT instruction POPCNT // POPCNT instruction AESNI // Advanced Encryption Standard New Instructions CLMUL // Carry-less Multiplication HTT // Hyperthreading (enabled) HLE // Hardware Lock Elision RTM // Restricted Transactional Memory RDRAND // RDRAND instruction is available RDSEED // RDSEED instruction is available ADX // Intel ADX (Multi-Precision Add-Carry Instruction Extensions) SHA // Intel SHA Extensions AVX512F // AVX-512 Foundation AVX512DQ // AVX-512 Doubleword and Quadword Instructions AVX512IFMA // AVX-512 Integer Fused Multiply-Add Instructions AVX512PF // AVX-512 Prefetch Instructions AVX512ER // AVX-512 Exponential and Reciprocal Instructions AVX512CD // AVX-512 Conflict Detection Instructions AVX512BW // AVX-512 Byte and Word Instructions AVX512VL // AVX-512 Vector Length Extensions AVX512VBMI // AVX-512 Vector Bit Manipulation Instructions AVX512VBMI2 // AVX-512 Vector Bit Manipulation Instructions, Version 2 AVX512VNNI // AVX-512 Vector Neural Network Instructions AVX512VPOPCNTDQ // AVX-512 Vector Population Count Doubleword and Quadword GFNI // Galois Field New Instructions VAES // Vector AES AVX512BITALG // AVX-512 Bit Algorithms VPCLMULQDQ // Carry-Less Multiplication Quadword AVX512BF16 // AVX-512 BFLOAT16 Instructions AVX512VP2INTERSECT // AVX-512 Intersect for D/Q MPX // Intel MPX (Memory Protection Extensions) ERMS // Enhanced REP MOVSB/STOSB RDTSCP // RDTSCP Instruction CX16 // CMPXCHG16B Instruction SGX // Software Guard Extensions SGXLC // Software Guard Extensions Launch Control IBPB // Indirect Branch Restricted Speculation (IBRS) and Indirect Branch Predictor Barrier (IBPB) STIBP // Single Thread Indirect Branch Predictors VMX // Virtual Machine Extensions // Performance indicators SSE2SLOW // SSE2 is supported, but usually not faster SSE3SLOW // SSE3 is supported, but usually not faster ATOM // Atom processor, some SSSE3 instructions are slower )
Variables ¶
This section is empty.
Functions ¶
func Detect ¶
func Detect()
Detect will re-detect current CPU info. This will replace the content of the exported CPU variable.
Unless you expect the CPU to change while you are running your program you should not need to call this function. If you call this, you must ensure that no other goroutine is accessing the exported CPU variable.
Types ¶
type ArmFlags ¶ added in v1.3.0
type ArmFlags uint64
ArmFlags contains detected ARM cpu features and characteristics
const ( /* extension instructions */ FP ArmFlags = 1 << iota ASIMD EVTSTRM AES PMULL SHA1 SHA2 CRC32 ATOMICS FPHP ASIMDHP ARMCPUID ASIMDRDM JSCVT FCMA LRCPC DCPOP SHA3 SM3 SM4 ASIMDDP SHA512 SVE GPA )
all special features for arm64 should be defined here
type CPUInfo ¶
type CPUInfo struct { BrandName string // Brand name reported by the CPU VendorID Vendor // Comparable CPU vendor ID VendorString string // Raw vendor string. Features Flags // Features of the CPU (x64) Arm ArmFlags // Features of the CPU (arm) PhysicalCores int // Number of physical processor cores in your CPU. Will be 0 if undetectable. ThreadsPerCore int // Number of threads per physical core. Will be 1 if undetectable. LogicalCores int // Number of physical cores times threads that can run on each core through the use of hyperthreading. Will be 0 if undetectable. Family int // CPU family number Model int // CPU model number CacheLine int // Cache line size in bytes. Will be 0 if undetectable. Hz int64 // Clock speed, if known Cache struct { L1I int // L1 Instruction Cache (per core or shared). Will be -1 if undetected L1D int // L1 Data Cache (per core or shared). Will be -1 if undetected L2 int // L2 Cache (per core or shared). Will be -1 if undetected L3 int // L3 Cache (per core, per ccx or shared). Will be -1 if undetected } SGX SGXSupport // contains filtered or unexported fields }
CPUInfo contains information about the detected system CPU.
var CPU CPUInfo
CPU contains information about the CPU as detected on startup, or when Detect last was called.
Use this as the primary entry point to you data.
func (CPUInfo) ADX ¶
ADX indicates support of Intel ADX (Multi-Precision Add-Carry Instruction Extensions)
func (CPUInfo) AVX ¶
AVX indicates support of AVX instructions and operating system support of AVX instructions
func (CPUInfo) AVX512BF16 ¶ added in v1.2.3
AVX512BF16 indicates support of
func (CPUInfo) AVX512BITALG ¶ added in v1.2.3
AVX512BITALG indicates support of AVX-512 Bit Algorithms
func (CPUInfo) AVX512DQ ¶
AVX512DQ indicates support of AVX-512 Doubleword and Quadword Instructions
func (CPUInfo) AVX512ER ¶
AVX512ER indicates support of AVX-512 Exponential and Reciprocal Instructions
func (CPUInfo) AVX512IFMA ¶
AVX512IFMA indicates support of AVX-512 Integer Fused Multiply-Add Instructions
func (CPUInfo) AVX512VBMI ¶
AVX512VBMI indicates support of AVX-512 Vector Bit Manipulation Instructions
func (CPUInfo) AVX512VBMI2 ¶ added in v1.2.3
AVX512VBMI2 indicates support of AVX-512 Vector Bit Manipulation Instructions, Version 2
func (CPUInfo) AVX512VNNI ¶ added in v1.2.2
AVX512VNNI indicates support of AVX-512 Vector Neural Network Instructions
func (CPUInfo) AVX512VP2INTERSECT ¶ added in v1.2.3
AVX512VP2INTERSECT indicates support of
func (CPUInfo) AVX512VPOPCNTDQ ¶ added in v1.2.3
AVX512VPOPCNTDQ indicates support of AVX-512 Vector Population Count Doubleword and Quadword
func (CPUInfo) AesNi ¶
AesNi indicates support of AES-NI instructions (Advanced Encryption Standard New Instructions)
func (CPUInfo) Amd3dnowExt ¶
Amd3dnowExt indicates support of AMD 3DNOW! Extended instructions
func (CPUInfo) ArmASIMDHP ¶ added in v1.3.0
Advanced SIMD half-precision floating point
func (CPUInfo) ArmASIMDRDM ¶ added in v1.3.0
Rounding Double Multiply Accumulate/Subtract (SQRDMLAH/SQRDMLSH)
func (CPUInfo) ArmATOMICS ¶ added in v1.3.0
Large System Extensions (LSE)
func (CPUInfo) Ia32TscAux ¶
Ia32TscAux returns the IA32_TSC_AUX part of the RDTSCP. This variable is OS dependent, but on Linux contains information about the current cpu/core the code is running on. If the RDTSCP instruction isn't supported on the CPU, the value 0 is returned.
Example ¶
This example will calculate the chip/core number on Linux Linux encodes numa id (<<12) and core id (8bit) into TSC_AUX.
ecx := CPU.Ia32TscAux() if ecx == 0 { fmt.Println("Unknown CPU ID") return } chip := (ecx & 0xFFF000) >> 12 core := ecx & 0xFFF fmt.Println("Chip, Core:", chip, core)
Output:
func (CPUInfo) LogicalCPU ¶
LogicalCPU will return the Logical CPU the code is currently executing on. This is likely to change when the OS re-schedules the running thread to another CPU. If the current core cannot be detected, -1 will be returned.
func (CPUInfo) MMXExt ¶
MMXExt indicates support of MMXEXT instructions (SSE integer functions or AMD MMX ext)
func (CPUInfo) RTCounter ¶
RTCounter returns the 64-bit time-stamp counter Uses the RDTSCP instruction. The value 0 is returned if the CPU does not support the instruction.
func (CPUInfo) SSE4A ¶
SSE4A indicates support of AMD Barcelona microarchitecture SSE4a instructions
func (CPUInfo) TSX ¶
TSX is split into HLE (Hardware Lock Elision) and RTM (Restricted Transactional Memory) detection. So TSX simply checks that.
func (CPUInfo) VM ¶
VM Will return true if the cpu id indicates we are in a virtual machine. This is only a hint, and will very likely have many false negatives.
func (CPUInfo) VPCLMULQDQ ¶ added in v1.2.3
VPCLMULQDQ indicates support of Carry-Less Multiplication Quadword
type Flags ¶
type Flags uint64
Flags contains detected cpu features and characteristics