/// <summary>
/// Allocates a new exchange buffer that allocates the specified amount of elements
/// on the current accelerator. Furthermore, it keeps a buffer of the same size in pinned
/// CPU memory to enable async memory transfers between the CPU and the GPU.
/// </summary>
/// <typeparam name="T">The element type.</typeparam>
/// <param name="accelerator">The associated acclerator to use.</param>
/// <param name="extent">The extent (number of elements to allocate).</param>
/// <param name="mode">The current allocation mode.</param>
/// <returns>The allocated exchange buffer.</returns>
public static ExchangeBuffer <T> AllocateExchangeBuffer <T>(
this Accelerator accelerator,
Index extent,
ExchangeBufferMode mode)
where T : struct
{
var gpuBuffer = accelerator.Allocate <T>(extent);
return(new ExchangeBuffer <T>(gpuBuffer, mode));
}
/// <summary>
/// Constructs the base class for all exchange buffer implementations.
/// </summary>
/// <param name="buffer">The memory buffer to use.</param>
/// <param name="mode">The exchange buffer mode to use.</param>
internal ExchangeBufferBase(MemoryBuffer <T, TIndex> buffer,
ExchangeBufferMode mode)
: base(buffer.Accelerator, buffer.Extent.Size)
{
cpuMemory = buffer.Accelerator is CudaAccelerator &&
mode == ExchangeBufferMode.PreferPagedLockedMemory
? CudaViewSource.Create(buffer.LengthInBytes)
: (ViewPointerWrapper)UnmanagedMemoryViewSource.Create(
buffer.LengthInBytes);
cpuMemoryPointer = cpuMemory.NativePtr.ToPointer();
}
/// <summary>
/// Constructs the base class for all exchange buffer implementations.
/// </summary>
/// <param name="accelerator">The associated accelerator.</param>
/// <param name="extent">The extent (number of elements).</param>
/// <param name="mode">The exchange buffer mode to use.</param>
protected ExchangeBufferBase(
Accelerator accelerator,
TIndex extent,
ExchangeBufferMode mode)
: base(accelerator, extent)
{
CPUMemory = Accelerator is CudaAccelerator &&
mode == ExchangeBufferMode.PreferPageLockedMemory
? CudaViewSource.Create(LengthInBytes)
: (ViewPointerWrapper)UnmanagedMemoryViewSource.Create(LengthInBytes);
var baseView = new ArrayView <T>(CPUMemory, 0, Length);
CPUView = new ArrayView <T, TIndex>(baseView, extent);
}
/// <summary>
/// Initializes a new basic exchange buffer.
/// </summary>
/// <param name="gpuBuffer">The parent GPU buffer to use.</param>
/// <param name="mode">The exchange buffer mode to use.</param>
/// <remarks>
/// CAUTION: The ownership of the <paramref name="gpuBuffer"/> is transferred to
/// this instance.
/// </remarks>
protected internal ExchangeBuffer(
MemoryBuffer <ArrayView1D <T, Stride1D.Dense> > gpuBuffer,
ExchangeBufferMode mode)
: base(gpuBuffer.Accelerator)
{
GPUBuffer = gpuBuffer;
CPUBuffer = Accelerator is CudaAccelerator &&
mode == ExchangeBufferMode.PreferPageLockedMemory
? CPUMemoryBuffer.CreatePinned(
Accelerator,
gpuBuffer.LengthInBytes,
gpuBuffer.ElementSize)
: CPUMemoryBuffer.Create(gpuBuffer.LengthInBytes, gpuBuffer.ElementSize);
CPUView = new ArrayView <T>(CPUBuffer, 0, gpuBuffer.Length);
}
/// <summary>
/// Allocates an exchange buffer using the given mode.
/// </summary>
/// <typeparam name="T">The element type.</typeparam>
/// <param name="accelerator">The accelerator instance.</param>
/// <param name="length">The number of elements to allocate.</param>
/// <param name="mode">The buffer mode to use.</param>
/// <returns>The allocated exchange mode.</returns>
public static ExchangeBuffer <T> AllocateExchangeBuffer <T>(
this Accelerator accelerator,
long length,
ExchangeBufferMode mode)
where T : unmanaged =>
new ExchangeBuffer <T>(accelerator.Allocate1D <T>(length), mode);