leavelet
1d630def95
In CP=8 + NSA-shared-KV + HiCache disagg-prefill, cache-hit prefill produced incoherent decode output. Cold prefill on CP was correct; pure CP without HiCache was correct. The bug lived at the HiCache load_cp / device-alloc interface. Root cause: cache_controller.load_cp called the plain mem_pool_device_allocator.alloc(logical_len), which returns logical pages with no CP owner-pattern preservation. Cold prefill instead uses alloc_extend_compute_owner with a zigzag owner pattern from build_in_seq_page_compute_owners. The saved CpHiCacheNodeMetadata.owned_positions records WHICH POSITIONS in the write-time alloc were owned by this rank. At load time, those same positions are applied to a new alloc whose per-position owner pattern is arbitrary -- each rank loads its host bytes into physical slots whose corresponding logical page is owned by a DIFFERENT rank. Attention's materialize_shared_token_kv_buffer reads from the owner's physical slot, which was never loaded. Result: garbage. Fix: - CpHiCacheNodeMetadata gains two required fields: page_owners (int8 per logical page, identical on all CP ranks) and page_size. __post_init__ validates; split() bisects page_owners by page index with a page-alignment check. - _write_cp derives page_owners from device_indices (page-first slot of each page -> logical page id -> layout.owner_for_logical_pages) and stores in both metadata-construction sites (zero-owned and normal). - New CPSharedPagedTokenToKVPoolAllocator.alloc_pages_with_owners() reuses _select_compute_owner_pages (with its tai-kernel fast path) and returns page-contiguous token locs whose per-page owner sequence equals the input. - load_cp now concats page_owners across nodes_to_load and calls alloc_pages_with_owners. On None (lane exhausted) the caller hits the retry-with-eviction path; further failure returns None and degrades to cache miss. No silent fallback to plain alloc -- that recreated the bug. - load_back retry path now calls _evict_for_compute_owner_lanes (module-top import) instead of plain evict(); this targets the deficit lane and gives the next alloc attempt a chance to satisfy it. - envs import moved to module top in cache_controller.py per code-review feedback. Removed an over-defensive owned_check.all().item() in load_cp that would have re-introduced the host-sync anti-pattern 97a9f850c removed -- the invariant is already guaranteed by alloc_pages_with_owners. Tests: 40 existing CpHiCacheNodeMetadata constructions migrated to pass the new required fields. 9 new metadata tests (validators + split page-alignment). 10 new allocator tests in test_alloc_pages_with_owners.py covering input-order preservation, lane exhaustion, release_pages fallback, debug-mode invariant. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Registered Tests
Tests under this directory are auto-discovered by run_suite.py via CI registration decorators.
Where Should I Put My New Test?
No server / engine launch required
| What you're testing | Directory | Requires |
|---|---|---|
| Component logic in isolation (cache, scheduler, config, parser, etc.) | unit/<module>/ |
CPU or GPU |
| CUDA kernel correctness | kernels/ |
GPU |
Server / engine launch required (E2E)
| What you're testing | Directory | Requires |
|---|---|---|
| Model inference correctness | models/, 4-gpu-models/, 8-gpu-models/ |
GPU |
| Feature-specific (OpenAI API, LoRA, speculative, distributed, VLM, etc.) | openai_server/, lora/, spec/, distributed/, ... |
GPU |
| Benchmarks (performance, accuracy, stress) | benchmark/ |
GPU |
| Platform-specific | amd/, ascend/ |
Vendor GPU |
See unit/README.md for unit test conventions.