# GPU counters and counter sample buffers Retrieve runtime data from a GPU device by sampling one or more of its counters. ## Discussion A GPU *counter* ([`MTLCounter`](/documentation/Metal/MTLCounter)) is typically a hardware feature that tracks a specific performance metric, such as timestamps before and after an important rendering stage. A *counter set* ([`MTLCounterSet`](/documentation/Metal/MTLCounterSet)) is a collection of related counters. A *counter sample buffer* ([`MTLCounterSampleBuffer`](/documentation/Metal/MTLCounterSampleBuffer)) represents the memory where a GPU device stores the data for a specific counter set. You can retrieve and inspect data from a GPU’s counter set with the following steps: 1. Inspect which GPU counter sets a GPU device supports (see [Confirming which counters and counter sets a GPU supports](/documentation/Metal/confirming-which-counters-and-counter-sets-a-gpu-supports)). 2. Make a counter sample buffer to store the data (see [Creating a counter sample buffer to store a GPU’s counter data during a pass](/documentation/Metal/creating-a-counter-sample-buffer-to-store-a-gpus-counter-data-during-a-pass)). 3. Instruct the GPU to save the counter set data to the buffer during a pass or an immediate mode command (see [Sampling GPU data into counter sample buffers](/documentation/Metal/sampling-gpu-data-into-counter-sample-buffers)). 4. Transform the counter set data into a standard type (see [Converting a GPU’s counter data into a readable format](/documentation/Metal/converting-a-gpus-counter-data-into-a-readable-format)). If you’re sampling data from a timestamp counter set ([`timestamp`](/documentation/Metal/MTLCommonCounterSet/timestamp)), you may need to convert the timestamps from the GPU’s clock to the CPU’s clock. See [Converting GPU timestamps into CPU time](/documentation/Metal/converting-gpu-timestamps-into-cpu-time) for more information. ## Topics ### Counters and counter sets [Confirming which counters and counter sets a GPU supports](/documentation/Metal/confirming-which-counters-and-counter-sets-a-gpu-supports) Check whether a GPU produces the runtime performance data you want to sample. [`MTLCounterSet`](/documentation/Metal/MTLCounterSet) A collection of individual counters a GPU device supports for a counter set. [`MTLCommonCounterSet`](/documentation/Metal/MTLCommonCounterSet) The name of a specific counter set that a GPU device can support. [`MTLCounter`](/documentation/Metal/MTLCounter) An individual counter a GPU device lists within one of its counter sets. [`MTLCommonCounter`](/documentation/Metal/MTLCommonCounter) The name of a specific counter that can appear in a GPU device’s counter sets. ### Counter sample buffers [Creating a counter sample buffer to store a GPU’s counter data during a pass](/documentation/Metal/creating-a-counter-sample-buffer-to-store-a-gpus-counter-data-during-a-pass) Make a buffer that provides a place for a GPU to save its runtime performance metrics as it runs a pass. [`MTLCounterSampleBufferDescriptor`](/documentation/Metal/MTLCounterSampleBufferDescriptor) A group of properties that configures the counter sample buffers you create with it. [`MTLCounterSampleBuffer`](/documentation/Metal/MTLCounterSampleBuffer) A specialized memory buffer that stores a GPU’s counter set data. [Sampling GPU data into counter sample buffers](/documentation/Metal/sampling-gpu-data-into-counter-sample-buffers) Retrieve a GPU’s counter data at a time the GPU supports. [`MTLCounterDontSample`](/documentation/Metal/MTLCounterDontSample) A sentinel value that instructs an encoder to skip sampling a counter as the GPU runs the encoder’s pass. ### Counter sample data output [Converting a GPU’s counter data into a readable format](/documentation/Metal/converting-a-gpus-counter-data-into-a-readable-format) Inspect and use the data within a GPU’s counter sample buffer by resolving it into a standard format. [`MTLCounterResultTimestamp`](/documentation/Metal/MTLCounterResultTimestamp) The data structure for storing the data you resolve from a timestamp counter set. [`MTLCounterResultStatistic`](/documentation/Metal/MTLCounterResultStatistic) The data structure for storing the data you resolve from a statistic counter set. [`MTLCounterResultStageUtilization`](/documentation/Metal/MTLCounterResultStageUtilization) The data structure for storing the data you resolve from a stage-utilization counter set. [`MTLCounterErrorValue`](/documentation/Metal/MTLCounterErrorValue) A sentinel value for an entry in a counter sample buffer that indicates the entry’s data is invalid. ### Timestamp data [Converting GPU timestamps into CPU time](/documentation/Metal/converting-gpu-timestamps-into-cpu-time) Correlate GPU events with CPU timelines by calculating the CPU time equivalents for GPU timestamps. [`MTLTimestamp`](/documentation/Metal/MTLTimestamp) The number of nanoseconds for a point in absolute time or Mach absolute time. ### Counter sample buffer errors [`MTLCounterSampleBufferError`](/documentation/Metal/MTLCounterSampleBufferError-swift.struct) The error codes that indicate why a GPU driver can’t create a counter sample buffer. ### Counter sample buffer errors [`MTLCounterSampleBufferError.Code`](/documentation/Metal/MTLCounterSampleBufferError-swift.struct/Code) The underlying error code type that indicates why a GPU driver can’t create a counter sample buffer. [`MTLCounterErrorDomain`](/documentation/Metal/MTLCounterErrorDomain) The domain for Metal counter sample buffer errors. --- 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)