Class SharedMemoryPipeOptions

Namespace

Nerdbank.Streams

Assembly

Nerdbank.Streams.dll

Options that control the behavior and resource allocation of a SharedMemoryDuplexPipe.

public sealed class SharedMemoryPipeOptions

Inheritance

object

SharedMemoryPipeOptions

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Properties

BaseDirectory

Gets or sets the directory in which to create the file that backs the shared memory, on platforms other than Windows. When null, defaults to /dev/shm if available, or the system temporary directory.

public string? BaseDirectory { get; set; }

Property Value

string

Remarks

This is ignored on Windows, where the shared memory is backed by the paging file and no file is created. Elsewhere the file is readable and writable only by the current user and is deleted as soon as the client opens it.

Capacity

Gets or sets the size, in bytes, of the shared memory buffer in each direction. This limits how many bytes the writer can have sent that the reader has not yet consumed. Must be a power of two of at least 2. Default is 1 MB.

public int Capacity { get; set; }

Property Value

int

Remarks

This does not limit message size. Most messages are serialized directly into shared memory without being copied. When a message is larger than the free space available, it is instead buffered in private memory and copied into shared memory in pieces as the reader frees up space, so the reader may receive it incrementally.

When the writer gets ahead of the reader and the buffer fills, whether with one large message or many small ones, FlushAsync(CancellationToken) waits asynchronously (without spinning) until the reader consumes enough data to make room. No data is dropped.

Each connection reserves about twice this many bytes of shared memory (one buffer per direction), shared by both processes. This reserves address space and, on Windows, counts toward the system commit limit, but the OS provides physical memory for a page only when it is first written. Whenever the reader has caught up, the writer starts again at the beginning of the buffer, so a connection only ever touches as much memory as it has had in flight at once. A generous capacity is therefore inexpensive unless it is actually filled. The memory is ordinary pageable memory: under memory pressure the OS may move it to the paging file or swap.

Choose a size that comfortably fits your largest typical messages: larger values let more messages skip the extra copy and reduce how often the writer must wait for the reader.

Signaling

Gets or sets the signaling mechanism used to notify the peer of new data or released space. Default is Auto.

public SharedMemorySignaling Signaling { get; set; }

Property Value

SharedMemorySignaling