Commit Graph
24 Commits
Author SHA1 Message Date
ViperEkura a29bdfae46 refactor: rework attention backend resolution
- explicit attn_backend() context wins over ASTR_BACKEND env
- polymorphic available()/supports_call() replace isinstance dispatch
- cache singleton backend instances to avoid hot-path allocation
- training (fwd=None) resolves cuda > flash > torch by capability
- flash dense supports mask-free calls only; masked training falls back to torch
2026-08-23 14:47:02 +08:00
ViperEkura 75304d084d refactor: unify CUDA skip guards in tests
- add skip_no_fp8 (CUDA + fp8_mm kernel + cc 8.9+) to tests/conftest.py
- use skip_no_cuda / skip_no_kernel / skip_no_fp8 directly in test modules
- drop _GPU alias and tests.extension.conftest re-exports
- remove unused imports (Union in hf_adapter, make_grpo_config in data conftest)
2026-08-22 21:08:06 +08:00
ViperEkura 16a55bb474 refactor: reorganize CUDA kernels into per-family directories
- move attention kernels to csrc/kernels/attention/ and rotary to rotary/
- add shared common/mma.cuh (mma_sync, ldmatrix) and device.cuh (sm checks)
- split fp8_mm into three-layer fp8/common.h, gemm.cuh, mm.cu
- fix fused FP8 GEMM ldmatrix lane indexing to fix OOB shared reads
- update extension ops, loader, and kernel tests
2026-08-22 20:40:31 +08:00
ViperEkura 3d3ea47d37 refactor: standardize packed 3d inference
- keep training attention on dense 4d tensors
- use packed 3d tensors with KV cache for inference
- extend CUDA rotary embedding to packed 3d inputs
- adapt torch, CUDA and FlashAttention backend dispatch

Benchmark: NVIDIA L20, BF16, 1B model, paged KV cache, CUDA Graph, prompt 512, generation 128 (median of 3 alternating runs)
- batch 1: 234.5 -> 242.6 tok/s (1.034x, +3.4%)
- batch 8: 1243.1 -> 1286.6 tok/s (1.035x, +3.5%)
2026-08-19 00:36:53 +08:00
ViperEkura 7580d80d45 perf: accelerate FP8 backward with fused fast kernel
- route dX/dW through the fused 128x64 fast kernel via contiguous transposes
- drop the legacy 64x64 kernel, cutting dX 1.55->0.38 ms and dW 1.28->0.26 ms
- sync all threads after cp.async.wait_group to fix sporadic NaN in large GEMMs
- add fp8_mm_prequant_fp8 custom op for FP8-in/FP8-out GEMM
2026-08-18 23:46:43 +08:00
ViperEkura cb51a3587b perf: optimize fused FP8 GEMM kernel 2026-08-18 19:56:15 +08:00
ViperEkura 6ac3b51496 refactor: separate extension ops and backends 2026-08-16 21:15:52 +08:00
ViperEkura 3406157431 refactor: standardize packed 3d inference
- keep training attention on dense 4d tensors
- use packed 3d tensors with KV cache for inference
- extend CUDA rotary embedding to packed 3d inputs
- adapt torch, CUDA and FlashAttention backend dispatch
2026-08-16 13:24:02 +08:00
ViperEkura 3fb4b8ab13 perf: use int32 paged KV indices
- store page-table, request-row, and cache-location indices as int32
- preserve CUDA graph replay with bit-exact logits and KV cache coverage
- improve B=1 decode latency by 1-6% across 1K-32K contexts on L20
2026-08-15 13:17:06 +08:00
ViperEkura 47b3ed4e44 feat: propagate attention backend across scheduler threads
- InferenceEngine/Scheduler accept an explicit backend
- capture request-level attn_backend context onto Task
- split prefill/decode batches by backend instance
- ASTR_BACKEND env overrides ContextVar as process-wide policy
- report resolved backend and CUDA-graph state in benchmark
2026-08-09 13:32:40 +08:00
ViperEkura 0c1b7664c1 refactor: split infer core into subpackages by concern
- Eliminate core/ directory into cache/, runtime/, network/ subpackages plus flat modules
- Split cache.py (647 lines) into cache/{buffer,strategy,pool}.py by layer
- Add explicit ContiguousStrategy, make AllocationStrategy a real ABC
- Move TaskCacheState to cache/strategy.py, drop string forward references
- Rename api/ to network/, server.py to app.py
- Move sample.py into runtime/ alongside executor and graph
- Simplify TaskCacheManager.__init__ to single pool param
- Expose pool.strategy and pool.req_pool as public properties
- Fix KVCache import in attention_backend.py (TYPE_CHECKING guard)
- Fix steady-state decode reading uninitialized position_ids on first step
2026-08-08 23:43:05 +08:00
ViperEkura 3fa7e66676 refactor: decouple task cache from PagePool and unify steady-state detection
- TaskCacheRegistry -> TaskCacheManager (independent, held by scheduler)
- TaskCacheState co-locates 5 parallel dicts into one dataclass
- AllocationStrategy base class + PagedStrategy subclass (page_size is a parameter)
- _rollback() helper for unified cleanup (no duplicate free paths)
- Task._kv_len + prefill_done property (explicit, no output_tokens proxy)
- Steady-state detection single-sourced in TaskCacheManager.bind()
- PagePool is now pure physical layer (no task knowledge)
- Removed dead _page_to_hash dict in RadixCache
2026-08-08 22:43:06 +08:00
ViperEkura e3ea850dc9 fix: default backend race, raise on explicit fallback
- _default_backend lazy init protected with threading.Lock
- attention() raises when explicit backend cannot handle call
- FlashAttnBackend rejects prefill with non-None attn_mask
- training test uses TORCH_NATIVE backend directly
2026-08-08 13:00:58 +08:00
ViperEkura 1b1f1a0707 fix: add dtype guard to FlashAttnBackend capability check
- _backend_supports now rejects fp32 for FlashAttnBackend (flash-attn only supports fp16/bf16), preventing runtime crash on fallback chain
- rename test_default_backend_is_torch_native to reflect multi-backend reality
- scheduler test fixture uses bf16 model (matches production, avoids unnecessary 3-step fallback chain)
2026-08-07 23:08:22 +08:00
ViperEkura 02469887f5 refactor: simplify inference engine and backend dispatch
- merge _generate_streaming/_generate_non_streaming into single _generate() with stream flag
- delete dead GenerationRequest class and generate_with_request method
- inline _next_token helper into generate_async
- replace flash-attn double-checked locking with functools.lru_cache
- extract _write_and_gather_kv helper shared by TorchNative/FlashAttn backends
- inline _kv_cache_is_contiguous into its sole call site in FlashAttnBackend
- change default backend priority from flash>cuda>torch to cuda>flash>torch
- add ASTR_BACKEND env var to override default backend at resolve time
- add supports_graph() static method to AttentionBackend ABC, override in CudaBackend
- replace isinstance(get_backend(), CudaBackend) with get_backend().supports_graph() in executor
- add torch.cuda.is_available() guard to CudaBackend.supports()
2026-08-07 22:28:48 +08:00
ViperEkura 0e7fe57d96 fix: use max_context_len for stable num_splits in paged decode
- PagedKV::host_kv_len now returns max_context_len instead of max_seq_len
- Eliminates grid-z instability for CUDA graph capture/replay
- Restore skip_no_kernel re-export accidentally removed by ruff --fix
2026-08-07 14:42:53 +08:00
ViperEkura 55ee258e95 style: fix ruff lint warnings
- Remove unused local variable b in attention_backend.py
- Remove unused variable rank0_sd in test_broadcast_state_dict.py
- Remove unused imports across test files
2026-08-07 14:17:48 +08:00
ViperEkura 6f49738991 feat: auto-select best available attention backend
- Default backend resolves to highest-priority available: flash -> cuda -> torch
- attention() falls back per-call for training/fp32/unsupported head_dim
- Re-apply index_copy_ for CUDA KV cache writes (index_put_ race mitigation)
2026-08-07 13:48:59 +08:00
ViperEkura 6f67ba8942 perf: move decode split partials to InferenceWorkspace
- Replace per-.cu-file static cached tensors with workspace-managed pre-allocated buffers

- InferenceWorkspace now owns decode_o_part / decode_ml_part (mirrors FlashInfer's workspace pattern)

- KVCache carries the buffers through the backend -> C++ kernel chain

- C++ kernels accept optional pre-allocated buffers; fallback to alloc_split_partials for backward compat

- Pre-allocates once at Executor init, zero allocation in the decode hot loop

- Prerequisite for CUDA-graph capture (all kernel addresses are stable)
2026-08-06 19:12:09 +08:00
ViperEkura 8152760b5f refactor : use factory for attention backends
- register built-in backends through BaseFactory
- derive benchmark choices from registered backends
- cover string selection and invalid backend names
2026-08-05 15:37:22 +08:00
ViperEkura a03504a280 perf: preallocate inference decode buffers
- add InferenceWorkspace with fixed-shape per-step buffers (input_ids, decode mask, KV bind metadata) for CUDA-graph capture
- bind_tasks derives seq_lens from the pool's own _task_len tracking, dropping the seq_lens parameter
- update decode metadata in-place (position_ids, seq_lens, kv_indptr) instead of re-allocating per step
- task_extend advances _task_len in contiguous mode so the pool tracks current length
- skip log_softmax when logprobs are not requested
2026-08-03 00:55:26 +08:00
ViperEkura 41dcf0feb9 feat: SGLang-style paged attention kernels replace page-table path
- PagedAttentionParams uses flat KV pool + req_to_token + kv_indptr/qo_indptr instead of page_table
- MMA split-KV decode and split-Q prefill kernels with indirect ragged-batch addressing
- Prefill kernel accepts 4D mask (causal-aware); decode kernel supports 2D mask
- CudaBackend is inference-only: kv_cache=None raises, no torch fallback
- benchmark.py: required --ckpt, --backend/--compare options
- Parallel build isolates build-temp/build-lib per subprocess
- Standalone test covers decode/prefill with mask, 27 cases pass
2026-08-01 15:41:25 +08:00
ViperEkura 738cb8f128 fix: broadcast ref/old model state_dict for FSDP
- Add broadcast_state_dict to sync state_dict from rank-0 to all ranks
- Fix create_ref_model returning None on non-rank-0 under FSDP
- Fix sync_old_model only updating old_model on rank-0 under FSDP
- Split skip_no_cuda/skip_no_kernel markers and hoist to top-level conftest
- Add distributed tests for broadcast_state_dict and create_ref_model
2026-07-31 08:32:22 +08:00
ViperEkura 3067a8e1a6 feat: unify attention backend with multi-dim mask support
- Add attention() functional entry delegating to active backend
- GQA/MLA forward calls attention() instead of inline cache/SDPA
- CUDA kernels support 2D/3D/4D mask via mask_h_stride field
- CudaBackend.fwd_decode builds 2D padding mask for mixed seq_lens
- KVCache.max_len precomputed in bind_tasks to avoid GPU sync
- batch==1 decode short-circuits mask=None
- Split tests into conftest, test_backend, test_backend_equivalence, test_kernel_mask
- 440 tests pass, L20 decode 1.44-1.60x speedup vs torch native
2026-07-30 20:38:34 +08:00