Intel® VTune™ Amplifier XE and Intel® VTune™ Amplifier for Systems Help
This metric represents a fraction of slots during which CPU was stalled due to front-end bandwidth issues, such as inefficiencies in the instruction decoders or code restrictions for caching in the DSB (decoded uOps cache). In such cases, the front-end typically delivers a non-optimal amount of uOps to the back-end.