queue.latency

A probe block resubmitted to the main queue every window. One reading per window regardless of activity, reporting the worst wait it saw.


Delivery	stream, interval
Mechanism	none
Requires	iOS 17+, basset 0.1.1+

Real output from basset request get, captured against a running app:

CAPTURED                  ELAPSED  INSTRUMENT

launch 7444895511331759249
2026-08-23T14:26:34.443Z  +0.0s    concurrency.queue.latency(dispatchQueue)
├─ queueLabel               main
├─ queueLatencyNanoseconds  108292
├─ windowNanoseconds        999983250
└─ occurrenceCount          1
2026-08-23T14:26:35.442Z  +1.0s    concurrency.queue.latency(dispatchQueue)
├─ queueLabel               main
├─ queueLatencyNanoseconds  163291
├─ windowNanoseconds        999667000
└─ occurrenceCount          1
2026-08-23T14:26:36.442Z  +2.0s    concurrency.queue.latency(dispatchQueue)
├─ queueLabel               main
├─ queueLatencyNanoseconds  177458
├─ windowNanoseconds        999416625
└─ occurrenceCount          1

Getting Started

SDK

CLI

Instruments

Reference