# CPU INFOrmation library [](https://github.com/pytorch/cpuinfo/blob/master/LICENSE) [](https://travis-ci.org/pytorch/cpuinfo) [](https://ci.appveyor.com/project/MaratDukhan/cpuinfo/branch/master) cpuinfo is a library to detect essential for performance optimization information about host CPU. ## Features - **Cross-platform** availability: - Linux, Windows, macOS, Android, and iOS operating systems - x86, x86-64, ARM, and ARM64 architectures - Modern **C/C++ interface** - Thread-safe - No memory allocation after initialization - No exceptions thrown - Detection of **supported instruction sets**, up to AVX512 (x86) and ARMv8.3 extensions - Detection of SoC and core information: - **Processor (SoC) name** - Vendor and **microarchitecture** for each CPU core - ID (**MIDR** on ARM, **CPUID** leaf 1 EAX value on x86) for each CPU core - Detection of **cache information**: - Cache type (instruction/data/unified), size and line size - Cache associativity - Cores and logical processors (hyper-threads) sharing the cache - Detection of **topology information** (relative between logical processors, cores, and processor packages) - Well-tested **production-quality** code: - 60+ mock tests based on data from real devices - Includes work-arounds for common bugs in hardware and OS kernels - Supports systems with heterogenous cores, such as **big.LITTLE** and Max.Med.Min - Permissive **open-source** license (Simplified BSD) ## Examples Log processor name: ```c cpuinfo_initialize(); printf("Running on %s CPU\n", cpuinfo_get_package(0)->name); ``` Detect if target is a 32-bit or 64-bit ARM system: ```c #if CPUINFO_ARCH_ARM || CPUINFO_ARCH_ARM64 /* 32-bit ARM-specific code here */ #endif ``` Check if the host CPU support ARM NEON ```c cpuinfo_initialize(); if (cpuinfo_has_arm_neon()) { neon_implementation(arguments); } ``` Check if the host CPU supports x86 AVX ```c cpuinfo_initialize(); if (cpuinfo_has_x86_avx()) { avx_implementation(arguments); } ``` Check if the thread runs on a Cortex-A53 core ```c cpuinfo_initialize(); switch (cpuinfo_get_current_core()->uarch) { case cpuinfo_uarch_cortex_a53: cortex_a53_implementation(arguments); break; default: generic_implementation(arguments); break; } ``` Get the size of level 1 data cache on the fastest core in the processor (e.g. big core in big.LITTLE ARM systems): ```c cpuinfo_initialize(); const size_t l1_size = cpuinfo_get_processor(0)->cache.l1d->size; ``` Pin thread to cores sharing L2 cache with the current core (Linux or Android) ```c cpuinfo_initialize(); cpu_set_t cpu_set; CPU_ZERO(&cpu_set); const struct cpuinfo_cache* current_l2 = cpuinfo_get_current_processor()->cache.l2; for (uint32_t i = 0; i < current_l2->processor_count; i++) { CPU_SET(cpuinfo_get_processor(current_l2->processor_start + i)->linux_id, &cpu_set); } pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpu_set); ``` ## Exposed information - [x] Processor (SoC) name - [x] Microarchitecture - [x] Usable instruction sets - [ ] CPU frequency - [x] Cache - [x] Size - [x] Associativity - [x] Line size - [x] Number of partitions - [x] Flags (unified, inclusive, complex hash function) - [x] Topology (logical processors that share this cache level) - [ ] TLB - [ ] Number of entries - [ ] Associativity - [ ] Covered page types (instruction, data) - [ ] Covered page sizes - [x] Topology information - [x] Logical processors - [x] Cores - [x] Packages (sockets) ## Supported environments: - [x] Android - [x] x86 ABI - [x] x86_64 ABI - [x] armeabi ABI - [x] armeabiv7-a ABI - [x] arm64-v8a ABI - [ ] ~~mips ABI~~ - [ ] ~~mips64 ABI~~ - [x] Linux - [x] x86 - [x] x86-64 - [x] 32-bit ARM (ARMv5T and later) - [x] ARM64 - [ ] PowerPC64 - [x] iOS - [x] x86 (iPhone simulator) - [x] x86-64 (iPhone simulator) - [x] ARMv7 - [x] ARM64 - [x] OS X - [x] x86 - [x] x86-64 - [x] Windows - [x] x86 - [x] x86-64 ## Methods - Processor (SoC) name detection - [x] Using CPUID leaves 0x80000002–0x80000004 on x86/x86-64 - [x] Using `/proc/cpuinfo` on ARM - [x] Using `ro.chipname`, `ro.board.platform`, `ro.product.board`, `ro.mediatek.platform`, `ro.arch` properties (Android) - [ ] Using kernel log (`dmesg`) on ARM Linux - Vendor and microarchitecture detection - [x] Intel-designed x86/x86-64 cores (up to Sunny Cove, Goldmont Plus, and Knights Mill) - [x] AMD-designed x86/x86-64 cores (up to Puma/Jaguar and Zen 2) - [ ] VIA-designed x86/x86-64 cores - [ ] Other x86 cores (DM&P, RDC, Transmeta, Cyrix, Rise) - [x] ARM-designed ARM cores (up to Cortex-A55, Cortex-A77, and Neoverse E1/N1) - [x] Qualcomm-designed ARM cores (Scorpion, Krait, and Kryo) - [x] Nvidia-designed ARM cores (Denver and Carmel) - [x] Samsung-designed ARM cores (Exynos) - [x] Intel-designed ARM cores (XScale up to 3rd-gen) - [x] Apple-designed ARM cores (up to Lightning and Thunder) - [x] Cavium-designed ARM cores (ThunderX) - [x] AppliedMicro-designed ARM cores (X-Gene) - Instruction set detection - [x] Using CPUID (x86/x86-64) - [x] Using `/proc/cpuinfo` on 32-bit ARM EABI (Linux) - [x] Using microarchitecture heuristics on (32-bit ARM) - [x] Using `FPSID` and `WCID` registers (32-bit ARM) - [x] Using `getauxval` (Linux/ARM) - [x] Using `/proc/self/auxv` (Android/ARM) - [ ] Using instruction probing on ARM (Linux) - [ ] Using CPUID registers on ARM64 (Linux) - Cache detection - [x] Using CPUID leaf 0x00000002 (x86/x86-64) - [x] Using CPUID leaf 0x00000004 (non-AMD x86/x86-64) - [ ] Using CPUID leaves 0x80000005-0x80000006 (AMD x86/x86-64) - [x] Using CPUID leaf 0x8000001D (AMD x86/x86-64) - [x] Using `/proc/cpuinfo` (Linux/pre-ARMv7) - [x] Using microarchitecture heuristics (ARM) - [x] Using chipset name (ARM) - [x] Using `sysctlbyname` (Mach) - [x] Using sysfs `typology` directories (ARM/Linux) - [ ] Using sysfs `cache` directories (Linux) - TLB detection - [x] Using CPUID leaf 0x00000002 (x86/x86-64) - [ ] Using CPUID leaves 0x80000005-0x80000006 and 0x80000019 (AMD x86/x86-64) - [x] Using microarchitecture heuristics (ARM) - Topology detection - [x] Using CPUID leaf 0x00000001 on x86/x86-64 (legacy APIC ID) - [x] Using CPUID leaf 0x0000000B on x86/x86-64 (Intel APIC ID) - [ ] Using CPUID leaf 0x8000001E on x86/x86-64 (AMD APIC ID) - [x] Using `/proc/cpuinfo` (Linux) - [x] Using `host_info` (Mach) - [x] Using `GetLogicalProcessorInformationEx` (Windows) - [x] Using sysfs (Linux) - [x] Using chipset name (ARM/Linux)