CPUFeature

CPUFeature is a tool for detecting CPU features on x86/AMD64 processors. In particular it is engineered to have very low overhead on import (~ 1 ms) and to detect features that are often important in high-performance computing where hybrid combinations of multi-threading and multi-processing are used. Detects CPU features such as:

• SIMD instruction support
• Number of cores (both virtual and physical)
• Number of CPUs on the motherboard.
• Cache sizes

It is written in C99. It supports Windows with MSVC and Linux with GCC/LLVM compilers. MacOSX should also work with GCC/LLVM. CPUFeature is licensed under Creative Commons Zero, so it may be freely incorporated as a submodule into your own projects.

CPUFeature is considered to be in an alpha state because while it is tested via GitHub Actions on a variety of platforms, we expect edge cases to appear.

Example

The module generates a dict called CPUFeature on import which contains useful information regarding optimization and compilation for the host. For my Intel i7-7820X Skylake CPU, it generates the following info:

> python -c "import cpufeature; cpufeature.print_features()"

=== CPU FEATURES === VendorId : GenuineIntel num_virtual_cores : 16 num_physical_cores : 8 num_threads_per_core : 2 num_cpus : 1 cache_line_size : 64 cache_L1_size : 32768 cache_L2_size : 1048576 cache_L3_size : 11534336 OS_x64 : True OS_AVX : True OS_AVX512 : True MMX : True x64 : True ABM : True RDRAND : True BMI1 : True BMI2 : True ADX : True PREFETCHWT1 : False MPX : True SSE : True SSE2 : True SSE3 : True SSSE3 : True SSE4.1 : True SSE4.2 : True SSE4.a : False AES : True SHA : False AVX : True XOP : False FMA3 : True FMA4 : False AVX2 : True AVX512f : True AVX512pf : False AVX512er : False AVX512cd : True AVX512vl : True AVX512bw : True AVX512dq : True AVX512ifma : False AVX512vbmi : False

Notes on Fields

• If num_threads_per_core > 1 likely Intel Hyperthreading (or equivalent architecture) is present. The physical core count may be unreliable in virtual environments.
• Cache sizes are in bytes.
• For AVX2, check AVX2 and OS_AVX2.
• For AVX512, check AVX512f and OS_AVX512. Python support for AVX512 instructions is highly limited outside of compilation with ICC. MSVC does not have AVX512 support until MSVC2017.

Authors

• Based on FeatureDetector by Alexander Yee (https://github.com/Mysticial/FeatureDetector).
• Ported to Python by Robert A. McLeod, who added detection of cores, and cache sizes.
• drfinkus contributed to AMD support.
• WidgetA contributed support for compilation with Clang.

Release Notes

0.2.1

• Under development.

0.2.0

• Added pre-build wheels via cibuildwheels and GitHub Actions for Python 3.6-3.9 on Linux/Windows/MacOSX.
• Added support for AMD processors.
• Added a script for valgrind to more easier locate problems when the module crashes.

0.1.1

• Fixes for compilation with clang.

0.1.0

• Added detection of processors, cores, and cache sizes
• Created Python wrapper around FeatureDetector
• Reduced FeatureDetector to C99 for better cross-platform compatibility