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# MTLPipelineBufferDescriptor

The mutability options for a buffer that a render or compute pipeline uses.

```
class MTLPipelineBufferDescriptor
```

## Overview

Metal can perform additional optimizations if you guarantee that neither the CPU nor the GPU modify a buffer’s contents before starting a pass. Use immutable buffers as much as possible to take advantage of Metal optimizations.

To declare that a buffer is immutable, set the [`mutability`](/documentation/Metal/MTLPipelineBufferDescriptor/mutability) property of their associated [`MTLPipelineBufferDescriptor`](/documentation/Metal/MTLPipelineBufferDescriptor) object to [`MTLMutability.immutable`](/documentation/Metal/MTLMutability/immutable).

## Topics

### Setting buffer mutability

[`mutability`](/documentation/Metal/MTLPipelineBufferDescriptor/mutability)

A mutability option that determines whether you can update a buffer’s contents before related commands use the buffer.

[`MTLMutability`](/documentation/Metal/MTLMutability)

The options that determine the mutability of a buffer’s contents.


---

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