Utilities

group utilities

Functions

constexpr bool is_pow2(std::size_t value) noexcept

Returns whether or not value is a power of 2.

Parameters:

value – [in] value to check.

Returns:

True if the input is a power of two with non-negative integer exponent, false otherwise.

constexpr bool is_supported_alignment(std::size_t alignment) noexcept

Returns whether or not alignment is a valid memory alignment.

Parameters:

alignment – [in] to check

Returns:

True if the alignment is valid, false otherwise.

constexpr std::size_t align_up(std::size_t value, std::size_t alignment) noexcept

Align up to nearest multiple of specified power of 2.

Parameters:

  • value – [in] value to align

  • alignment – [in] amount, in bytes, must be a power of 2

Returns:

the aligned value

constexpr std::size_t align_down(std::size_t value, std::size_t alignment) noexcept

Align down to the nearest multiple of specified power of 2.

Parameters:

  • value – [in] value to align

  • alignment – [in] amount, in bytes, must be a power of 2

Returns:

the aligned value

constexpr bool is_aligned(std::size_t value, std::size_t alignment) noexcept

Checks whether a value is aligned to a multiple of a specified power of 2.

Parameters:

  • value – [in] value to check for alignment

  • alignment – [in] amount, in bytes, must be a power of 2

Returns:

true if aligned

inline bool is_pointer_aligned(void *ptr, std::size_t alignment = CUDA_ALLOCATION_ALIGNMENT) noexcept

Checks whether the provided pointer is aligned to a specified alignment.

Parameters:

  • ptr – [in] pointer to check for alignment

  • alignment – [in] required alignment in bytes, must be a power of 2

Returns:

true if the pointer is aligned

void prefetch(void const *ptr, std::size_t size, rmm::cuda_device_id device, rmm::cuda_stream_view stream)

Prefetch memory to the specified device on the specified stream.

This function is a no-op if the pointer is not to CUDA managed memory.

Throws:

rmm::cuda_error – if the prefetch fails.

Parameters:

  • ptr – The pointer to the memory to prefetch

  • size – The number of bytes to prefetch

  • device – The device to prefetch to

  • stream – The stream to use for the prefetch

template<typename T>
void prefetch(cuda::std::span<T const> data, rmm::cuda_device_id device, rmm::cuda_stream_view stream)

Prefetch a span of memory to the specified device on the specified stream.

This function is a no-op if the buffer is not backed by CUDA managed memory.

Throws:

rmm::cuda_error – if the prefetch fails.

Parameters:

  • data – The span to prefetch

  • device – The device to prefetch to

  • stream – The stream to use for the prefetch

Variables

static constexpr std::size_t RMM_DEFAULT_HOST_ALIGNMENT = {alignof(std::max_align_t)}

Default alignment used for host memory allocated by RMM.

static constexpr std::size_t CUDA_ALLOCATION_ALIGNMENT = {256}

Default alignment used for CUDA memory allocation.