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.
We use cpu_features as a git submodule to detect CPU features, e.g. AVX. There are two options to get the required code:
will automatically clone submodules as well. In case you missed that, you can just run:
that'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.
arm_cortex_a72_hardfp_native.cmake
arm_cortex_a53_hardfp_native.cmake
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 moving from the GNU General Public License version 3.0 (GPLv3) to the GNU Lesser General Public License version 3.0 (LGPLv3). At this point in time, much of the code in the repository is still GPL-licensed, but new contributors are asked to use the LGPLv3 for their code contributions. Existing contributors are very kindly requested to also allow LPGL-licensing by adding their name to the file AUTHORS_GRANTING_LGPL_LICENSE.txt
.