VOLK is a sub-project of GNU Radio. Please see http://libvolk.org for bug tracking, documentation, source code, and contact information about VOLK. See https://www.gnuradio.org/ for information about GNU Radio.
VOLK is the Vector-Optimized Library of Kernels. It is a library that contains kernels of hand-written SIMD code for different mathematical operations. Since each SIMD architecture can be very different and no compiler has yet come along to handle vectorization properly or highly efficiently, VOLK approaches the problem differently.
For each architecture or platform that a developer wishes to vectorize for, a new proto-kernel is added to VOLK. At runtime, VOLK will select the correct proto-kernel. In this way, the users of VOLK call a kernel for performing the operation that is platform/architecture agnostic. This allows us to write portable SIMD code.
Bleeding edge code can be found in our git repository at https://www.gnuradio.org/git/volk.git/.
For detailed instructions see http://libvolk.org/doxygen/using_volk.html
See these steps for a quick build guide.
$ mkdir build
$ cd build
$ cmake ..
$ make
$ make test
$ sudo make install
# You might want to explore "make -j[SOMEVALUE]" options for your multicore CPU.
# Perform post-installation steps
# Linux OS: Link and cache shared library
$ sudo ldconfig
# macOS/Windows: Update PATH environment variable to point to lib install location
# volk_profile will profile your system so that the best kernel is used
$ volk_profileWe use cpu_features as a git submodule to detect CPU features, e.g. AVX. There are two options to get the required code:
git clone --recursive https://github.com/gnuradio/volk.gitwill automatically clone submodules as well. In case you missed that, you can just run:
git submodule update --init --recursivethat'll pull in missing submodules.
To build for these boards you need specify the correct cmake toolchain file for best performance.
Note: There is no need for adding extra options to the compiler for 64 bit.
- Raspberry Pi 4
arm_cortex_a72_hardfp_native.cmake - Raspberry Pi 3
arm_cortex_a53_hardfp_native.cmake
$ mkdir build && cd build
$ cmake -DCMAKE_TOOLCHAIN_FILE=../cmake/Toolchains/arm_cortex_a72_hardfp_native.cmake ..
# make -j4 might be faster
$ make
$ make test
$ sudo make install
# volk_profile will profile your system so that the best kernel is used
$ volk_profileWe want to make sure everyone feels welcome. Thus, we follow our Code of Conduct.
We are happy to accept contributions. Please refer to our contributing guide for further details.
Also, make sure to read the Developer's Certificate of Origin and make sure to sign every commit with git commit -s.
We maintain a CHANGELOG for every release. Please refer to this file for more detailed information. We follow semantic versioning as outlined in our versioning guide.
VOLK aims to be portable to as many platforms as possible. We can only run tests on some platforms.
Currently VOLK aims to run with optimized kernels on x86 with SSE/AVX and ARM with NEON.
We run tests on a variety of Ubuntu versions and aim to support as many current distros as possible. The same goal applies to different OSes. Although this does only rarely happen, it might occur that VOLK does not work on obsolete distros, e.g. Ubuntu 12.04.
We want to make sure VOLK works with C/C++ standard compliant compilers. Of course, as an open source project we focus on open source compilers, most notably GCC and Clang.
We want to make sure VOLK compiles on a wide variety of compilers. Thus, we target AppleClang and MSVC as well. Mind that MSVC lacks aligned_alloc support for aligned arrays. We use MSVC specific instructions in this case which cannot be free'd with free.
VOLK is migrating from the GNU General Public License v3.0 or later (GPL-3.0-or-later) to the GNU Lesser General Public License v3.0 or later (LGPL-3.0-or-later). At this point in time, much of the code in the repository is still GPL-licensed. New contributors are required to use the LGPLv3+ for their code contributions. Existing contributors are very kindly requested to re-submit their GPL-3.0-or-later license code contributions to LGPL-3.0-or-later by adding their name, GitHub handle, and email address(es) used for VOLK commits to the file AUTHORS_RESUBMITTING_UNDER_LGPL_LICENSE.md.
VOLK is ready for a VOLK 3.0 release which marks our final switch to LGPL.