libcu++ 1.2.0 (CUDA Toolkit 11.1)

libcu++ 1.2.0 adds <cuda/pipeline>/cuda::pipeline, a facility for coordinating cuda::memcpy_async operations. This release introduces ABI version 3, which is now the default.

Supported ABI versions: 3 (default) and 2.

Included in: CUDA 11.1.

ABI Breaking Changes

• ABI version 3 has been introduced and is now the default. A new ABI version was necessary to improve the performance of cuda::[std::]barrier by changing its alignment. Users may define _LIBCUDACXX_CUDA_ABI_VERSION=2 before including any libcu++ or CUDA headers to use ABI version 2, which was the default for the 1.1.0 / CUDA 11.0 release. Both ABI version 3 and ABI version 2 will be supported until the next major CUDA release.

New Features

• <cuda/pipeline>: cuda::pipeline, a facility for coordinating cuda::memcpy_async operations.
• <cuda/std/version>: API version macros _LIBCUDACXX_CUDA_API_VERSION, _LIBCUDACXX_CUDA_API_VERSION_MAJOR, _LIBCUDACXX_CUDA_API_VERSION_MINOR, and _LIBCUDACXX_CUDA_API_VERSION_PATCH.
• ABI version switching: users can define _LIBCUDACXX_CUDA_ABI_VERSION to request a particular supported ABI version. _LIBCUDACXX_CUDA_ABI_VERSION_LATEST is set to the latest ABI version, which is always the default.

Other Enhancements

• <cuda/latch>/<cuda/semaphore>: <cuda/*> headers added for cuda::latch, cuda::counting_semaphore, and cuda::binary_semaphore. These features were available in prior releases, but you had to include <cuda/std/latch> and <cuda/std/semaphore> to access them.
• NVCC + GCC 10 support.
• NVCC + Clang 10 support.

libcu++ 1.1.0 (CUDA Toolkit 11.0)

libcu++ 1.1.0 introduces the world's first implementation of the Standard C++20 synchronization library: <cuda/[std/]barrier>, <cuda/std/latch>, <cuda/std/semaphore>, cuda::[std::]atomic_flag::test, cuda::[std::]atomic::wait, and cuda::[std::]atomic::notify*. An extension for managing asynchronous local copies, cuda::memcpy_async is introduced as well. It also adds <cuda/std/chrono>, <cuda/std/ratio>, and most of <cuda/std/functional>.

ABI Breaking Changes

• ABI version 2 has been introduced and is now the default. A new ABI version was introduced because it is our policy to do so in every major CUDA toolkit release. ABI version 1 is no longer supported.

API Breaking Changes

• Atomics on Pascal + Windows are disabled because the platform does not support them and on this platform the CUDA driver rejects binaries containing these operations.

New Features

• <cuda/[std/]barrier>: C++20's cuda::[std::]barrier, an asynchronous thread coordination mechanism whose lifetime consists of a sequence of barrier phases, where each phase allows at most an expected number of threads to block until the expected number of threads arrive at the barrier. It is backported to C++11. The cuda::barrier variant takes an additional cuda::thread_scope parameter.
• <cuda/barrier>: cuda::memcpy_async, asynchronous local copies. This facility is NOT for transferring data between threads or transferring data between host and device; it is not a cudaMemcpyAsync replacement or abstraction. It uses cuda::[std::]barriers objects to synchronize the copies.
• <cuda/std/functional>: common function objects, such as cuda::std::plus, cuda::std::minus, etc. cuda::std::function, cuda::std::bind, cuda::std::hash, and cuda::std::reference_wrapper are omitted.

Other Enhancements

• Upgraded to a newer version of upstream libc++.
• Standalone NVRTC support.
• C++17 support.
• NVCC + GCC 9 support.
• NVCC + Clang 9 support.
• Build with warnings-as-errors.

Issues Fixed

• Made __cuda_memcmp inline to fix ODR violations when compiling multiple translation units.

libcu++ 1.0.0 (CUDA Toolkit 10.2)

libcu++ 1.0.0 is the first release of libcu++, the C++ Standard Library for your entire system. It brings C++ atomics to CUDA: <cuda/[std/]atomic>. It also introduces <cuda/std/type_traits>, <cuda/std/cassert>, <cuda/std/cfloat>, <cuda/std/cstddef>, and <cuda/std/cstdint>.

New Features

• <cuda/[std/]atomic>:
  • cuda::thread_scope: An enumeration that specifies which group of threads can synchronize with each other using a concurrency primitive.
  • cuda::atomic<T, Scope>: Scoped atomic objects.
  • cuda::std::atomic<T>: Atomic objects.
• <cuda/std/type_traits>: Type traits and metaprogramming facilities.
• <cuda/std/cassert>: assert, an error-reporting mechanism.
• <cuda/std/cstddef>: Builtin fundamental types.
• <cuda/std/cstdint>: Builtin integral types.
• <cuda/std/cfloat>: Builtin floating point types.

Known Issues

• Due to circumstances beyond our control, the NVIDIA-provided Debian packages install libcu++ to the wrong path. This makes libcu++ unusable if installed from the NVIDIA-provided Debian packages and may interfere with the operation of your host C++ Standard Library.