Issue efficiency
Issue efficiency describes how often a scheduler issues work relative to the issue opportunities being counted. It must be interpreted with the metric’s cycle and scheduler scope.
How it works
A scheduler can fail to issue because no warp is eligible or because the required resource cannot accept work. Ready warps that are not selected are different from stalled warps. Architecture-specific issue capacity prevents turning this into one universal formula.
Four resident warps. Two ready. One selected.
Work through an example
In a one-issue-per-cycle teaching model, issuing in six of eight observed cycles gives a 75% issue rate. This says nothing by itself about active lanes or useful FLOPs per instruction.
Where the term can mislead
A high issue rate can coexist with divergence, unnecessary instructions or a poorly chosen algorithm.
Connect the idea
Take it into practice
Continue with the existing concept, apply it to an interview problem, or follow a course lesson. Access requirements are shown before you open a page.
New to GPUs? Start with the free execution-model concept.
Sources and scope
Examples here are teaching calculations, not measured GPU performance. Consult the linked documentation for the exact device, instruction and tool version. Source review: 25 October 2026.