Upgrade Gpu Version

Upgrade the AFD GPU backend

Run this workflow as a gated, version-neutral state machine. Resolve the exact current and target vLLM revisions, inventory AFD behavior, and pass the architecture gate before editing production code. Preserve supported AFD behavior on the target upstream architecture; do not preserve an obsolete implementation shape merely because an older release required it.

Read the repository AGENTS.md before acting. Read references/upgrade-workbook.md completely for evidence tables, source-diff commands, handoff records, and report templates. List and read every references/*lessons.md file before upstream analysis. Treat lessons as historical failure patterns, never as target-version instructions; re-derive every applicable fact from the exact current and target sources. Read references/documentation-refresh.md only after the required GPU validation gates pass and before refreshing public support claims.

Task modes

Choose exactly one mode from the request. Do not silently combine modes.

• planning-audit: perform read-only identity, inventory, upstream diff, architecture-gate, and staged-plan work. Do not edit AFD or allocate GPUs.
• implementation: implement the approved upgrade in bounded adaptations, add focused tests, and pass the static/unit gate. Continue to GPU validation only when the request includes it and the required environment is available.
• final-validation: freeze an already selected AFD revision and run read-only native and AFD validation. Do not fix production code unless the user changes the mode to implementation.

Record the selected mode. If it is ambiguous and the stopping point changes what may be edited or whether GPUs may be allocated, ask once before proceeding.

Hard boundaries

• Treat current vLLM and target vLLM as immutable revisions. Resolve both refs to full commit SHAs before diffing or editing. If either ref, SHA, or exact source tree is unavailable, mark FREEZE_IDENTITY BLOCKED and every later phase SKIPPED; do not substitute a historical lesson or installed package.
• Discover the current ref from repository evidence when possible. Require the target vLLM ref and a local vLLM source repository. Never infer a target revision from the newest installed package or an unpinned branch.
• Define the AFD base revision as the immutable pre-upgrade AFD commit named by the issue/RFC or proven by branch ancestry; do not assume origin/main or the current merge-base. Define the target AFD mirrored version as the package or compatibility version the repository will publish for the target vLLM, not a branch name. Cite the repository policy; use NOT_APPLICABLE when no mirrored version policy exists.
• Do not modify, switch, or check out another revision in a user-provided vLLM source directory. If its HEAD is the target SHA, use it read-only. Otherwise use git show in read-only audits, or create a separate detached worktree only when workspace writes are in scope. Read a missing current tree the same way without disturbing the provided checkout.
• Record the intended target Python, PyTorch build CUDA and C++ ABI, vLLM artifact/build identity, CUDA toolkit/runtime, NVIDIA driver, host compiler, NCCL, device compute capability/count/topology, and model paths. Inventory plugin-owned GPU native sources separately. Planning may mark unavailable hardware evidence UNKNOWN; final validation must stop when the exact runtime or required hardware cannot be established.
• Do not edit AFD production code before the architecture gate passes. If a major architecture change is found, stop and report the required design decision. Do not silently remove a supported feature or build a broad compatibility layer around it.
• Preserve unrelated dirty changes. Record branch, HEAD, and status before work. Stop if user changes overlap planned files. Never reset, discard, stage, or commit unrelated paths.
• Never modify the vLLM source tree to make AFD pass. Keep target worktrees read-only after creation.
• Prefer native vLLM extension points, inheritance, and composition. Do not add a new public connector, runner, protocol, or runtime abstraction unless the exact target contract proves existing interfaces insufficient; treat a broad cross-component expansion as an architecture-gate decision.
• Follow AGENTS.md for every copied or patched function: exact target signature and return type, source/reason/functionality comments, narrowly marked AFD deltas, focused AFD and non-AFD tests, performance impact, and a removal or upstream plan.
• Access known upstream members directly. Do not hide drift with broad getattr, hasattr, exception swallowing, Any, or version-probing wrappers.
• In implementation mode, keep each coherent upstream cause and its focused regression tests together. Create local signed-off commits only when commits are in scope; never push, publish, merge, or open a PR unless separately requested.
• Run every required non-accuracy GPU E2E case before final accuracy. Never use a limited accuracy run as final qualification, and never hard-code a test count in this skill.

Evidence authority

Use this order when evidence conflicts:

1. exact current and target vLLM source revisions;
2. current AFD source, tests, package pins, and normative repository contracts;
3. results from the frozen validation cell;
4. historical *lessons.md files as hypotheses to check, not facts to carry.

An old workaround, file path, runner generation, test count, topology, or CUDA behavior remains applicable only after target-source verification.

Subagent orchestration

Use distinct subagents when available to separate analysis, implementation, testing, and review. The primary agent owns phase state, architecture decisions, the integrated diff, commits, and the final report. Subagent conclusions are evidence, not automatic gate decisions.

• Keep analysis agents read-only. Split by vLLM history or AFD surface and require exact SHAs, paths, symbols, classifications, invariants, and tests.
• Dispatch implementation agents only after the architecture gate. Give each one non-overlapping AFD file set and one upstream root cause. Prohibit branch changes, staging, commits, pushes, and upstream edits.
• Keep test agents read-only for tracked files. Make GPU E2E agents read ../run-e2e/SKILL.md and AGENTS.md. Serialize GPU jobs unless reservations, devices, ports, writable caches, logs, processes, and cleanup ownership are explicitly isolated.
• Keep review agents independent and read-only. Require simplicity and minimality review first, then exact upstream signatures, patch markers, ownership, call order, performance risks, isolation, and test coverage.

Record every handoff using the workbook. Never test or review a worktree while an implementation agent is writing it. Inspect returned diffs and command results directly before accepting them.

Use this loop for each adaptation in implementation mode:

ANALYZE -> PRIMARY GATE -> IMPLEMENT -> FOCUSED TEST
        -> INDEPENDENT REVIEW -> PRIMARY COMMIT -> REGRESSION GATE

Required phase record

At every phase boundary record:

phase: <name>
status: PASS | FAIL | BLOCKED | STOPPED | SKIPPED
evidence: <SHAs, files, commands, tests, logs, or reports>
blocker: <none or exact blocker>
next_allowed_action: <one action>

Do not enter a later required phase when an earlier phase is FAIL, BLOCKED, or STOPPED.

FREEZE_IDENTITY
  -> INVENTORY_AFD_CONTRACTS
  -> DIFF_VLLM
  -> ARCHITECTURE_GATE
  -> PRODUCE_STAGED_PLAN
  -> IMPLEMENT_ATOMIC_ADAPTATIONS
  -> STATIC_AND_UNIT_GATE
  -> TARGET_NATIVE_GPU_CONTROL
  -> GPU_BASIC_E2E_GATE
  -> GPU_ACCURACY_GATE
  -> DOCUMENTATION_REFRESH_GATE
  -> FINAL_AUDIT
  -> CAPTURE_LESSONS_AND_REPORT

Phase 0 — Freeze identity

Record the task mode; AFD checkout, branch, HEAD, immutable pre-upgrade base revision and its evidence, dirty status, and Python environment; vLLM source path, HEAD, branch, and dirty status; current and target refs plus resolved SHAs; and any detached read-only worktrees.

Discover the current vLLM ref in this order:

1. pyproject.toml, lockfile, and package metadata;
2. compatibility constants, patch annotations, design matrices, README, GPU guides, recipes, CI, and active upgrade RFC;
3. installed package versions and adjacent checkout state as corroboration only.

Resolve annotated tags to commits. If authoritative sources disagree, mark the identity phase BLOCKED rather than choosing the convenient value.

Record the target AFD published package/compatibility version and validate it against the repository's mirrored-version policy, or record NOT_APPLICABLE with evidence. Record the intended target stack: Python; PyTorch version, build CUDA, and C++11 ABI; vLLM source/package/native-artifact identity; CUDA toolkit and runtime; NVIDIA driver; nvcc; host compiler; NCCL; GPU model and compute capability; device count and interconnect/topology; runner generation; and model/checkpoint path. In final validation, record the effective values and reconcile them with the intended tuple.

Phase 1 — Inventory AFD contracts

Build the inventory before reading the upstream diff. Use source search as the authority and documentation as supporting evidence. Cover at least:

• version pins, runtime checks, package build/install, plugin registration, CPU-safe imports, and non-AFD isolation;
• every compatibility patch and copied upstream method, including copies outside afd_plugin/compat/patches/**;
• GPU Attention and FFN workers, model runners, EngineCore integration, KV-cache and scheduler ownership, startup, failure propagation, and shutdown;
• model registration, role-aware construction, native lifecycle, forward paths, parameter ownership, quantization, and weight filtering/loading;
• GPU connectors, payloads, custom ops, process groups, rank/device/topology mapping, synchronization, ordering, errors, and cleanup;
• CUDA Graph capture/replay, compile behavior, dummy/warmup runs, DBO/uBatch, TP/DP/EP/PP, profiling, sampling, request output, and memory accounting;
• GPU native sources and build interfaces in AFD and target vLLM, including artifact ownership, build flags, supported compute capabilities, and ABI;
• focused tests, complete GPU E2E scenarios, recipes, documentation, CI, and release metadata;
• shared files whose change may require NPU regression evidence without making an NPU support claim.

For every patched or copied function, record AFD target, current upstream source and symbol, exact signature, marker blocks, preserved invariant, state/lifecycle owner, direct consumers, focused AFD and non-AFD tests, and removal/upstream plan.

Freeze the current supported feature matrix. Discover all represented runner generations, models, connectors, eager/graph modes, DBO/uBatch cells, gate placements, TP/DP/EP/PP topologies, profiling modes, quantization/EPLB paths, accuracy cases, and negative/isolation cases. An omitted feature is UNKNOWN, not implicitly out of scope.

For planning-audit, the minimum sufficient inventory is every AFD dependency on the changed upstream surface, every copied or patched upstream method, and every currently supported feature cell affected by that surface. Prove an area unaffected with source-search evidence. If a user-imposed path or time bound leaves an affected surface UNKNOWN, block the architecture gate rather than calling the inventory complete.

Phase 2 — Diff vLLM

Compare current vLLM SHA to target vLLM SHA. Begin with rename-aware name status and stats, first-parent history, and focused function-context diffs. Map every relevant upstream change to AFD consumers and classify it:

• MECHANICAL: import move, rename, or exact signature change with equivalent ownership and behavior;
• BEHAVIORAL: defaults, schema, state lifetime, call order, device mapping, graph behavior, or ownership changed while the AFD invariant still maps;
• ARCHITECTURAL: an execution generation, stable seam, lifecycle owner, feature, protocol, or cross-component boundary was removed or conceptually replaced.

For copied upstream logic, reconstruct method by method:

1. use the exact target upstream function as the new skeleton;
2. use current AFD markers and focused tests as the local-difference ledger;
3. use current supported AFD behavior as the semantic contract;
4. replay only still-required AFD differences into the target skeleton;
5. verify decorators, signature, return type, call order, state ownership, resource lifetime, hot-path cost, graph/compile behavior, and shutdown.

Do not mechanically apply an upstream old-to-new diff onto an AFD copy. Check whether target vLLM added an extension point that lets the patch be removed or replaced by delegation.

Phase 3 — Architecture gate

Stop without production edits when any of these is true:

• the target vLLM revision and requested CUDA/PyTorch/toolchain tuple are not a reproducible supported environment;
• the GPU worker/model-runner generation or lifecycle is replaced and AFD needs redesign rather than local adaptation;
• a required patch seam disappears without an equivalent stable target, or it can no longer be expressed as target upstream logic plus small AFD markers;
• upstream removes or disables a supported graph, DBO, parallelism, model, connector, or profiling contract and continuing would require silent feature deletion or validation bypass;
• model split, expert/gate ownership, scheduler/KV ownership, connector payload, topology, process group, sampling/output, or cleanup contracts change across multiple subsystems without a one-to-one invariant mapping;
• preserving behavior requires a new public protocol, broad core rewrite, extensive upstream copies, reflection-heavy compatibility, or hidden fallback;
• the selected PyTorch/vLLM native artifacts, CUDA runtime, C++ ABI, or target compute capability cannot form one executable target cell;
• the required CUDA/driver/compiler/NCCL transition cannot be built and tested as one exact target environment.

A moved implementation is not automatically architectural. Continue only when inputs, outputs, ordering, ownership, and lifetime map cleanly and the adaptation remains narrow. On stop, use the workbook's architecture report and leave AFD production files unchanged.

Phase 4 — Produce a staged plan

Create an upstream-to-AFD impact matrix and a reviewable implementation plan. For each stage record upstream cause, expected files, preserved invariant, patch disposition, focused and regression tests, graph/performance/distributed risks, documentation impact, and removal or upstream contribution plan.

Classify each compatibility seam as remove, delegate/inherit, port as an exact-version adapter, propose upstream, or stop. Do not use a scoring system instead of making the architectural judgment.

In planning-audit mode, emit the plan, patch audit, feature matrix, exclusions, and evidence gaps, then mark later phases SKIPPED and stop without writes. If an earlier gate is blocked, emit only a blocker-resolution plan naming the exact missing evidence and next allowed actions; label the implementation impact matrix and staged plan unavailable rather than filling them with hypotheses.

Phase 5 — Implement atomic adaptations

In implementation mode, create or use a dedicated upgrade branch only when branch changes are in scope; otherwise record and preserve the current branch. Before each edit batch record files, upstream cause, invariant, tests, risks, and patch removal/upstream plan.

Implement in dependency order unless the impact graph proves another order:

1. version/package contract and CPU-safe imports;
2. compatibility patches and plugin initialization order;
3. model construction, native lifecycle, role ownership, and weight policy;
4. Attention/FFN workers and model runners, EngineCore, KV/scheduler ownership;
5. connectors, payloads, distributed topology, and device mapping;
6. CUDA Graph, DBO/uBatch, parallelism, profiling, warmup, and cleanup;
7. focused tests and repository-owned E2E scenarios needed for qualification.

Use existing connector and runner interfaces unless the architecture gate explicitly approved a new boundary. Preserve native model forward, loading, and runtime behavior wherever the target provides a usable seam. Do not change shared runtime code to conceal an incomplete GPU adaptation.

For each retained patch, copy the target function, match its exact signature, mark only AFD differences, test selected and non-AFD branches, and document performance and removal/upstream plans. Remove an obsolete patch only after proving target upstream absorbed the behavior.

After each coherent adaptation passes focused checks and independent review, inspect the staged diff and create a signed-off local commit when commits are in scope. Keep source changes and focused regression tests together.

Phase 6 — Static and unit gate

Before allocating GPUs, inspect the repository's current CI and test entry points and run their actual commands. Cover:

• diff, lint, format, compile, import, and package build/install checks;
• exact target runtime import and plugin registration;
• version pin/runtime check consistency;
• target vLLM native-module provenance/import plus PyTorch build-CUDA and C++11 ABI consistency;
• a clean AFD package build and import for every plugin-owned compiled GPU extension that exists in the target tree;
• exact patch signatures, decorators, return types, comments, and markers;
• affected focused tests, then the complete CPU/unit suite;
• model construction and weight policy, worker/runner contracts, connector ordering/topology, graph/DBO helpers, cleanup, and non-AFD isolation;
• dependency consistency such as python -m pip check in the target runtime.

Treat collection or import failure as a version/environment failure until the identity tuple is proven. Import, construction, dummy execution, or server startup alone never proves GPU support.

If AFD has no plugin-owned compiled GPU source, record NOT_APPLICABLE with the inspected build files instead of inventing a build requirement. Do not rebuild vLLM merely for preflight when the repository requires an installed runtime; verify that runtime's native artifact and reserve source builds for an approved target-build qualification.

In implementation mode without requested hardware validation, report all GPU phases SKIPPED and readiness implemented, GPU-unverified.

Phase 7 — Target native GPU control

Before AFD E2E, prove the exact target vLLM runtime can load the selected model and serve at least one real eager GPU request with AFD disabled. Keep model, checkpoint, runner generation, quantization, prompt, sampling, and comparable parallelism aligned with the first AFD cell. Record startup, weight loading, readiness, output/correctness oracle, resource use, and cleanup.

On the reserved target GPU, execute the smallest target-native kernel or operator smoke that proves the loaded artifact runs on the recorded compute capability. When AFD owns a compiled GPU extension, run its smallest real operator smoke before the request; otherwise record NOT_APPLICABLE.

Follow AGENTS.md for remote access and GPU scheduler ownership. Never treat a free-looking device as authorization. If native construction, loading, readiness, or request execution fails, preserve the first useful traceback and stop AFD parity validation. A fallback setting creates a separate validation cell and must not silently replace the requested target.

Phase 8 — GPU basic E2E gate

Read and follow ../run-e2e/SKILL.md for hardware detection, provisioning, pytest selection, live output, skip reporting, and cleanup. Do not duplicate or override its backend-selection logic in this skill. AGENTS.md remains the authority for scheduler use and remote test artifacts.

Run the complete marker-based GPU non-accuracy suite before accuracy:

1. feature scenarios;
2. model scenarios;
3. any repository-owned GPU upgrade scenario not covered by those categories.

Use enough reserved GPUs to avoid capacity skips when claiming a full upgrade. Every skip must map to a documented unsupported or explicitly excluded cell; a new, unexplained, or hardware-capacity skip is not a full pass. Record actual collected and executed counts from pytest instead of assuming a fixed suite size.

Verify behavior, not only launch: real responses, eager/graph comparisons, actual CUDA Graph capture/replay, actual DBO stages, TP/DP/EP collectives, profiler traces, error propagation, and cleanup as represented by repository tests. After every run verify the exact experiment PID tree, ports, GPU processes, scheduler state, and IPC resources are clean.

For each failure, preserve the cell, command, environment, first useful root traceback, logs, resource state, and cleanup. In final-validation mode classify and report without source edits. In implementation mode trace one root cause, add the narrowest regression test, implement one minimal fix, repeat focused review, then rerun the failed case and complete basic gate.

Phase 9 — GPU accuracy gate

Enter only after the complete basic E2E gate passes. Delegate all GPU accuracy execution to run-e2e. Run every repository-owned GPU accuracy case, including eager and graph variants, with no dataset limit for final qualification. A limited run is diagnostic evidence only.

On failure, preserve metrics and artifacts and compare the exact native and AFD cells. Never lower thresholds or widen tolerance to make an upgrade pass unless the user explicitly approves a separately justified policy change. After a code fix, rerun the complete basic gate before full accuracy.

Phase 10 — Documentation refresh gate

Enter only after required basic and accuracy gates pass. Read references/documentation-refresh.md completely before editing upgrade documentation. Refresh exact runtime claims, GPU guides, recipes, design/patch inventories, contributor templates, and release metadata from the validation ledger.

Distinguish hardware validated, unit validated, implemented but unvalidated, unsupported, and shared-code only. Preserve intentionally historical versions and measurements. Never infer NPU support from a GPU result or relabel an old recipe as target evidence.

In final-validation mode without documentation-write scope, audit and report required changes instead of editing them.

Phase 11 — Final audit

Audit version pins, source annotations, patch inventory, support matrices, package/release metadata, recipes, GPU documentation, CI, test discovery, and historical branch notes. Confirm every retained patch has focused AFD and non-AFD coverage plus a removal/upstream plan. Reconcile every public support claim with an exact validation cell and list all exclusions.

Report CPU-safe and GPU evidence separately. Shared-code unit evidence is not a GPU hardware claim; GPU evidence is not an NPU claim. Performance claims require matching measured evidence rather than successful functional E2E alone.

Phase 12 — Capture lessons and report

After a completed implementation upgrade, create a new version-specific file under references/ using the workbook template. Name it <YYYYMMDD>-<current-vllm>-to-<target-vllm>-lessons.md; sanitize refs and use a short SHA when no immutable tag exists. Never overwrite an earlier lesson.

Record exact identities, upstream changes, adaptations, failures, misleading attempts, useful validation, documentation conflicts, remaining debt, and the next-upgrade checks. Separate reusable principles from version-specific facts. Link raw evidence instead of copying large logs. Have an independent read-only review when available, then commit the lesson only when repository writes and commits are in scope.

In planning or validation-only mode, do not create a lesson file. Include the same fields in the final report as proposed lessons instead.

Use the workbook completion template to report:

• mode, all refs and full SHAs, target AFD version, and exact CUDA stack;
• architecture decision, impact matrix, staged plan, patch dispositions, and feature matrix;
• changed components and each local commit/root cause;
• static/unit, native build/ABI, native control, basic E2E, and full accuracy commands/results;
• actual pass/fail/error/skip counts, metrics, logs, cleanup, and exclusions;
• documentation consistency and intentionally preserved history;
• remaining private seams, performance observations, release blockers, and branch/publish status;
• readiness separated into GPU-validated, shared-code, and unverified claims.

Declare the requested scope complete only when every required earlier phase passes. A full GPU upgrade requires immutable compatible identity, architecture approval, focused and complete CPU gates, native GPU control, complete basic GPU E2E with no unexplained skips, full accuracy, documentation consistency, clean resource teardown, and an evidence-backed final report.