There are two common scenarios where spill/fill has catastrophic performance implications: - Workloads that are LSU-bound, like simple per-pixel image operatio

There are two common scenarios where spill/fill has catastrophic performance implications: - Workloads that are LSU-bound, like simple per-pixel image operations and level 1 and level 2 BLAS[1]. Here every spill is taking up two LSU dispatch slots that would otherwise be used for "real work". - Spilled loop-carried dependencies in tight loops; here you're simply adding latency to the critical path. Both are fairly rare in "generic" code, but very real concerns for compute kernels. [1] The BLAS operations have few enough buffers that spill/fill never actually happens in practice, but more complex operations on multiple buffers do run into this.