Shader ALU & FPU Pipeline: Review Checklist

Review checklist

Review Checklist for Shader ALU & FPU Pipeline centers on ALU/FPU occupancy, pipeline hazard frequency, and instruction latency overlap. The objective is to connect profiler evidence to root-cause mechanism and release-safe action.

• Workload scope and target KPI are explicitly documented.

• Profiler + counter evidence is reproducible with revision tags.

• Bottleneck classification is proved with mechanism-level traces.

• Mitigation includes owner, blast radius, and rollback criteria.

• End-to-end benchmark matrix confirms closure.

• Owners signed: shader core owner, compiler backend owner, performance engineer.

Signoff ownership

GPU OWNERSHIP LAYERS — Shader ALU & FPU Pipeline

artifact area     owner
----------------  ----------------------------
architecture    shader core owner
RTL/microarch   compiler backend owner
software/tools  performance engineer

Rule: each metric needs a named owner before signoff.

GPU deep dive

Shader-core throughput is gated by issue policy, register-bank access, and pipeline hazard behavior.

Concept diagram

SM CORE LOOP

warp schedulers -> issue ports -> ALU/FPU/Tensor pipelines
scoreboard + register file gate progress

Metric graph

SM BOTTLENECK MIX

dependency stalls   ███████
bank conflicts      ████
pipeline bubbles    ███

Reports and artifacts

• SM IPC dashboard

• issue stall taxonomy

• register-bank conflict log

• shader unit utilization

Mini case study

Compiler register allocation shifted operand banking, doubling RF conflicts and causing a 14% shader regression.

Debug branches

• Inspect scoreboard wait-depth trends

• Track RF conflicts by instruction class

• Separate front-end issue loss from backend saturation

Senior review question

Ask: which metric and benchmark pairing proves this topic is truly closed in production context?

Key takeaways

• Always pair micro-kernel metrics with end-to-end workload impact.

• Lock toolchain, driver, and launch metadata before comparing performance results.

Common pitfalls

• Optimizing occupancy without checking memory-system saturation.

• Comparing profiler captures from different driver or compiler builds.

• Declaring wins without reproducible accuracy and performance gates.

Review checklist explanation

A checklist is not bureaucracy here; it is how GPU teams avoid confusing local wins with product wins. Every signoff item should protect against a known class of false confidence.

For Shader ALU & FPU Pipeline, the minimum checklist is workload scope, ALU/FPU occupancy, pipeline hazard frequency, and instruction latency overlap, artifact evidence (pipeline timing chart, instruction mix breakdown, and hazard replay report), bottleneck classification, owner, rollback path, and full matrix validation.

If the change affects architecture or RTL, include correctness and PPA evidence. If it affects compiler/runtime policy, include compatibility and deployment evidence. If it affects physical design, include timing, IR, thermal, and observability evidence.