# MTLComputePassSampleBufferAttachmentDescriptor A configuration that instructs the GPU where to store counter data from the beginning and end of a compute pass. ``` class MTLComputePassSampleBufferAttachmentDescriptor ``` ## Overview For more context about configuring sample buffer attachments for compute passes, see [Sampling GPU data into counter sample buffers](/documentation/Metal/sampling-gpu-data-into-counter-sample-buffers). That article is one of a series in [GPU counters and counter sample buffers](/documentation/Metal/gpu-counters-and-counter-sample-buffers) about sampling Metal hardware counters for performance measurement. ## Topics ### Configuring the sample buffer attachment [`sampleBuffer`](/documentation/Metal/MTLComputePassSampleBufferAttachmentDescriptor/sampleBuffer) A specialized memory buffer that the GPU uses to store its counter data during a compute pass. [`startOfEncoderSampleIndex`](/documentation/Metal/MTLComputePassSampleBufferAttachmentDescriptor/startOfEncoderSampleIndex) An index within a counter sample buffer that tells the GPU where to store counter data from the start of a compute pass. [`endOfEncoderSampleIndex`](/documentation/Metal/MTLComputePassSampleBufferAttachmentDescriptor/endOfEncoderSampleIndex) An index within a counter sample buffer that tells the GPU where to store counter data from the end of a compute pass. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)