leavelet
1923fcd67e
The bs=1 MLA/index prefetchers replaced their consume-side trailing-range NCCL all-reduce with the staging exchange: fill current rows straight into this round's staging span (token-KV collapses to one cached index_copy; the index fill kernel is just pointed at the staging page inverse), cp_symm_barrier, then gather ALL current pages — this rank's own included — from the stagings into the prefetched dense buffer. The symm+prefetcher FAIL_FAST is gone. Rank-uniformity moves with it: staging registration now also happens in maybe_create (batch-logical gates, before any per-rank miss can diverge), because with a prefetcher active the sync compose runs only on per-rank misses and its lazy collective registration would hang. A hit/miss divergence itself stays barrier-safe — both the prefetch consume and the sync-compose fallback execute exactly one begin_round + barrier per (layer, kind), and the counting barrier is shape-free (unlike the AR pair it replaces, which would shape-mismatch). Found by the new index test phase: the fill/remap kernel family skips page id 0 as the SGLang dummy page, so a 0-based first staging slot was never written. The staging layout now reserves row 0 (slot of current page i = i + 1) for every kind, matching the convention instead of depending on per-kernel behavior. Launch-path cost: per-(kind,parity) peer pointer tables and the [pool|staging] concatenations are precomputed/cached (identity pinned by holding the pool-table reference); all prefetch descriptors, staging row indices, and mixed_locs are built once per batch. Validated on g0033 8xH200: 151 unit tests; 8-rank byte-exactness for token sync symm (8 layers), index sync symm (4 layers, new phase), and MLA + index prefetch consume_prefix_with_current vs the legacy sync compose. Co-Authored-By: Claude Fable 5 <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.