> ## Documentation Index
> Fetch the complete documentation index at: https://docs.basset.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# gpu.latency

> How long the GPU takes to answer a trivial piece of work, as a measure of what it is already carrying

Submits a trivial probe through a swizzled Metal command queue on a fixed
interval, timing how long it waits before the GPU starts it and how long it
takes once started.

| | |
| - | - |
| [Delivery](/instruments/metadata) | stream, interval |
| Mechanism | swizzle |
| [Requires](/instruments/metadata) | iOS 17+, hardware only, no simulator, basset 0.1.1+ |

Real output from `basset request get`, captured while drawing through a
`CAMetalLayer`:

```
CAPTURED                  ELAPSED  INSTRUMENT

launch 5600321339416417470
2026-08-23T16:10:27.314Z  +0.0s    metal.gpu.latency(gpu)
├─ windowNanoseconds            999978250
├─ sampleCount                  1
├─ occurrenceCount              1
├─ frameBudgetNanoseconds       16666666
├─ gpuWaitNanoseconds           115042
├─ gpuWaitPeakNanoseconds       115042
├─ gpuExecutionNanoseconds      5583
└─ gpuExecutionPeakNanoseconds  5583
2026-08-23T16:10:28.313Z  +1.0s    metal.gpu.latency(gpu)
├─ windowNanoseconds            999274125
├─ sampleCount                  1
├─ occurrenceCount              1
├─ frameBudgetNanoseconds       16666666
├─ gpuWaitNanoseconds           278375
├─ gpuWaitPeakNanoseconds       278375
├─ gpuExecutionNanoseconds      5250
└─ gpuExecutionPeakNanoseconds  5250
2026-08-23T16:10:29.313Z  +2.0s    metal.gpu.latency(gpu)
├─ windowNanoseconds            999866541
├─ sampleCount                  1
├─ occurrenceCount              1
├─ frameBudgetNanoseconds       16666666
├─ gpuWaitNanoseconds           250750
├─ gpuWaitPeakNanoseconds       250750
├─ gpuExecutionNanoseconds      5542
└─ gpuExecutionPeakNanoseconds  5542
```


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