GS Is Bottleneck
GS Is Bottleneck metric represents the percentage of time that the geometry shader (GS) stage is a bottleneck. This is the percent of time the GS unit is stalling the Vertex Shader/Domain Shader (VS/DS; upstream unit) and starving the Stream Output Logic (SOL; downstream unit).
If GS Is Bottleneck is 90, then the geometry shader stage is a bottleneck (stalling both the upstream and downstream units) 90% of the time.
A geometry shader can output new primitives from its input primitives. New vertices can be generated from a set of input vertices. However, generating too many new primitives can result in a bottleneck in the GS stage. In the Intel® GPA Frame Analyzer, try editing the geometry shader in the Shaders tab. For example, try reducing the number of primitives that the geometry shader generates.