Decode prealloc and transfer queues own the receiver lifetime once a request leaves the queue. The abort and transfer-failure paths were removing requests after streaming/releasing KV state without clearing the receiver, leaving backend-specific request tracking behind. The scheduler idle check also ignored decode retracted requests, so idle housekeeping could run while decode handoff state still existed.
Constraint: This is a manual port of upstream 18989f3d48 onto a locally diverged decode queue implementation.
Rejected: Direct cherry-pick | current decode queue compaction and streamer APIs differ from upstream.
Confidence: high
Scope-risk: narrow
Directive: Any path that removes a DecodeRequest from prealloc or transfer ownership must clear its kv_receiver unless ownership is explicitly transferred.
Tested: remote cjy-glm5-new pytest test/registered/unit/disaggregation/test_decode_queue_compaction.py -q: 16 passed
Tested: remote cjy-glm5-new pytest test/registered/unit/disaggregation/test_decode_queue_compaction.py test/registered/unit/observability/test_scheduler_metrics_load.py -q: 17 passed
Tested: git diff --check on modified files
Not-tested: full disaggregated decode E2E under live traffic
Spec v1 EAGLE now follows the same model-config-gated MTP index reuse contract as spec v2. This lets models that declare index_share_for_mtp_iteration reuse the first draft step's NSA/DSA topk indices across internal MTP iterations while keeping the unsafe topk>1 case disabled.
Constraint: select_top_k_tokens can reorder hidden rows when topk > 1, so carried topk indices are only valid under topk == 1.
Rejected: Enable reuse unconditionally | models without the config flag may not have compatible MTP index semantics.
Rejected: Broaden to target-to-draft index reuse | separate semantic change with different correctness risks.
Confidence: high
Scope-risk: narrow
Directive: Keep spec v1 and spec v2 MTP index reuse semantics aligned, including the topk==1 guard and per-draft-forward cleanup.
Tested: python -m pytest test/registered/spec/eagle/test_eagle_v2_draft_extend_contract.py -q
Tested: python -m py_compile python/sglang/srt/speculative/eagle_worker.py test/registered/spec/eagle/test_eagle_v2_draft_extend_contract.py
Not-tested: full spec v1 GLM5 online throughput run
EAGLE V2 draft MTP can avoid recomputing NSA/DSA indexer topk across internal draft iterations when the model declares that those indices are shareable. The port follows the upstream narrow contract: store per-forward topk on ForwardBatch, enable reuse only for topk=1, and clear the transient state after draft_forward.
Constraint: topk > 1 reorders hidden rows in select_top_k_tokens, so carried topk indices would no longer match the hidden states.
Rejected: Reuse target-side topk for draft | broader semantic change not covered by the upstream fix or current tests.
Rejected: Skip loading draft indexer weights | separate memory optimization with correctness risk for models that do not enable MTP index sharing.
Confidence: high
Scope-risk: narrow
Directive: Do not enable index_share_for_mtp_iteration without preserving the topk==1 guard and per-draft-forward cleanup.
Tested: python -m pytest test/registered/spec/eagle/test_eagle_v2_draft_extend_contract.py -q
Tested: python -m py_compile python/sglang/srt/speculative/eagle_worker_v2.py python/sglang/srt/models/deepseek_nextn.py python/sglang/srt/model_executor/forward_batch_info.py test/registered/spec/eagle/test_eagle_v2_draft_extend_contract.py
Not-tested: full GLM5 EAGLE throughput/accuracy run
NSA spec-v2 draft-extend graph replay was still using host-derived sequence lengths and the draft-decode backend allowlist. That kept NSA on eager draft-extend for spec-v2 and left seq_lens_cpu.max()/list-to-GPU tensor construction on the decode critical path.
This ports the small upstream DSA metadata fixes into the local NSA backend: size the captured graph page table to req_to_token width, use the static captured page-table width for graph replay, split v2 draft-extend from variable-length v1 draft-extend, and decide draft-extend graph support from the prefill-style backend.
Constraint: Current branch does not have the full upstream needs_cpu_seq_lens scheduler/FutureMap infra.
Rejected: Cherry-pick the full DSA fused metadata generation series | too broad and overlaps with local NSA fused metadata-copy code.
Confidence: medium
Scope-risk: moderate
Directive: Do not collapse DRAFT_EXTEND and DRAFT_EXTEND_V2 here; v1 keeps variable accept lengths while v2 must stay graph-static.
Tested: local pytest test/registered/spec/eagle/test_eagle_v2_draft_extend_contract.py -q (19 passed)
Tested: local py_compile on nsa_backend.py, nsa_backend_mtp_precompute.py, eagle_worker_v2.py
Tested: remote g0034 cjy-glm5-new pytest test/registered/spec/eagle/test_eagle_v2_draft_extend_contract.py -q (19 passed)
Tested: remote g0034 cjy-glm5-new py_compile on nsa_backend.py, nsa_backend_mtp_precompute.py, eagle_worker_v2.py
Not-tested: full decode E2E with SGLANG_ENABLE_SPEC_V2=1
Spec-v2 decode was paying unnecessary scheduler-side copy and replay costs: hidden states were copied back to CPU even when not requested, overlap result D2H ran on the forward stream, and draft graph replay issued several small copies separately.
Port the focused upstream optimizations without taking the larger spec-v2 relay refactor: gate hidden-state D2H on return_hidden_states, run result copies on copy_stream with pinned async D2H, use stride arange for draft select_index, and group small draft graph replay copies while keeping the large hidden-state DMA copy separate.
Constraint: Current branch carries local GLM/NSA/PD/CP changes, so upstream spec-v2 large refactors are not safe to cherry-pick wholesale.
Rejected: Cherry-pick upstream spec-v2 relay/dataclass refactor | too broad for this performance fix and conflicts with current branch structure
Rejected: Copy hidden states unconditionally | default chat output does not consume them after draft extend
Confidence: medium
Scope-risk: moderate
Directive: Keep result-copy lifetime tied to copy_done; do not move copy_to_cpu back onto forward_stream without measuring decode throughput.
Tested: local py_compile for changed production files and new test
Tested: local git diff --check
Tested: remote g0034 cjy-glm5-new as ubuntu on /sgl-workspace/sglang-tai: pytest -q -p no:cacheprovider test_generation_batch_result_copy.py test_eagle_worker_v2_cp_hidden.py test_spec_utils.py
Not-tested: full two-node decode throughput A/B after restart
Spec-v2 draft extend can receive token ids from producers whose dtype is not already int64, while DP collective paths require a stable integer dtype across ranks. EAGLE draft CUDA graph replay also pads raw batches to a captured batch size, so the metadata/replay path must see seq_lens_sum consistent with the padded seq_lens and then restore the caller-visible raw value.
Constraint: Keep this as a narrow correctness port from upstream rather than pulling the larger spec-v2 refactor chain.
Rejected: Cherry-pick broader attention-backend and decode-result refactors | current branch lacks the same upstream forward-context scaffolding and would require a separate port.
Confidence: high
Scope-risk: narrow
Directive: Do not remove the seq_lens_sum restore without rechecking padded EAGLE draft CUDA graph metadata construction.
Tested: python -m pytest test/registered/spec/eagle/test_eagle_v2_draft_extend_contract.py -q
Tested: remote g0034/cjy-glm5-new PYTHONPATH=python python3 -m pytest test/registered/spec/eagle/test_eagle_v2_draft_extend_contract.py -q
Not-tested: full multi-node GLM5 spec-v2 decode startup smoke
Co-authored-by: OmX <omx@oh-my-codex.dev>
Port the fix-decode spec-v2 ownership and plan-stream fixes onto the current branch. Draft extend now keeps the scheduler-owned batch lengths committed until acceptance, binds the draft runner to the draft-extend attention backend, keeps speculative KV allocation monotonic, and lets non-graph target verify initialize metadata after DP padding. The worker also records rebound tensors on the forward stream and orders plan-stream metadata work after current-stream inputs are available.
Constraint: fix-decode commits cd8e47ed9c and 60e3956d9c address CUDA illegal-address failures in spec-v2 decode warmup paths.
Rejected: Cherry-pick the commits blindly | the current branch has intervening decode changes, so a minimal manual port kept the patch surface to the affected files.
Confidence: medium
Scope-risk: moderate
Directive: Do not move target-verify non-graph metadata initialization back into prepare_for_v2_verify without validating DP padding and NSA metadata ordering.
Tested: RED local pytest test/registered/spec/eagle/test_eagle_v2_draft_extend_contract.py -q failed 8/8 before production changes.
Tested: PYTHONPATH=python python3 -m pytest test/registered/spec/eagle/test_eagle_v2_draft_extend_contract.py -q passed 8/8 locally.
Tested: PYTHONPATH=python python3 -m py_compile python/sglang/srt/speculative/eagle_info_v2.py python/sglang/srt/speculative/eagle_worker_v2.py python/sglang/srt/speculative/spec_utils.py passed locally.
Tested: Remote g0034:cjy-glm5-new pytest for test/registered/spec/eagle/test_eagle_v2_draft_extend_contract.py passed 8/8, plus remote py_compile for the three speculative modules.
Tested: Local and remote sha256 sums matched for all four synced files.
Not-tested: Full spec-v2 decode server restart/warmup under production traffic.
Rank-local CP HiCache async write queues can drain at different times across ranks. Radix structural decisions that consult those local queues can diverge, so backup-pending state now lives on the replicated radix node and uses a separate backup lock ref from request locks. Commit and rollback clear the replicated marker, and split/prune/hit-count probes use the marker rather than local pending dictionaries.
Constraint: CP ranks must make identical radix structural decisions even when local async write acknowledgements drain at different times
Rejected: Drain write acknowledgements before every split/prune decision | still rank-local and adds hot-path synchronization
Rejected: Treat backup lock_ref as a normal request lock | hides the distinction between request protection and backup-pending protection
Confidence: high
Scope-risk: moderate
Directive: Do not derive CP HiCache split/prune/write-through decisions from pending_host_backups or ongoing_write_through without a replicated node marker
Tested: local py_compile python/sglang/srt/mem_cache/hiradix_cache.py python/sglang/srt/mem_cache/radix_cache.py
Tested: local git diff --check
Tested: remote cjy-glm5-new pytest replicated marker test plus targeted CP HiCache metadata subset, 10 passed
Not-tested: full test_cp_hicache_metadata.py because current branch has unrelated fixture drift around enable_cp_l3/cp_shared_l2_page_allocator/running-count setup
Co-authored-by: OmX <omx@oh-my-codex.dev>
Drives _cp_l3_reserve_reloads directly against a real CpSharedL2PageAllocator:
- same-tick state (l3rl object committed-and-live + node attached -> attach_ok False)
no longer raises 'duplicate live reservation'; the candidate is dropped and the
request left un-held (re-matches the inserted node).
- WITHOUT the recheck (attach_ok forced True = pre-fix path) the identical state
raises the duplicate error -> proves the recheck is load-bearing.
- an in-flight reload still piggybacks (recheck sits after the dedup, not before).
- a genuine clean miss still reserves (no false-positive starvation).
CPU unit test (register_cpu_ci, stage-a-test-cpu); runs in the dev-cu13 container.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Replaces the O(victims*candidates) per-iteration greedy argmin rescan in
_plan_cp_load_back_owner_lane_evictions with a leaf-up min-heap. The score
(-contribution, -unlock, slru_priority, node.id) depends on the current deficits, so a
static heap is not equivalent; instead use LAZY RE-EVALUATION: a popped entry is consumed
only if its score still matches the node's current score (deficits unchanged since push),
else it is re-pushed with the fresh score. Stale scores are always optimistic (contribution
= sum(min(counts[o], deficits[o])) and the ancestor-unlock contribution only shrink as
deficits shrink), so the first up-to-date popped entry is exactly the global argmin the full
rescan would have picked -> PROVABLY EQUIVALENT, with the same leaf-up eligibility +
ancestor-unlock + parent-push. Determinism/rank-uniformity preserved (selection decided by
the total-ordered score; the heap insertion seq only orders structurally-equal tuples).
Equivalence proven by test: a verbatim reference greedy + a randomized property test (300
seeds, single- AND multi-owner deficits, non-uniform counts exercising the lazy-re-eval
boundary, varied SLRU priorities) asserting byte-identical (victims, planned_freed,
remaining), plus an explicit leaf-up + ancestor-unlock case (child-then-parent). 14 planner
tests pass (1 pre-existing unrelated EAGLE-tail failure unchanged).
Micro-bench (V100, candidates=2000 deficit=7877, benchmark/hicache/bench_cp_owner_lane_planner.py):
A. ORIGINAL (.item() x cp, no memo) 50.06s
B. memo + bincount (greedy) 0.494s (101x)
C. lazy-re-eval heap 0.162s (309x; 3.0x over B) selection A==B==C identical
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A CP4 prefill server hung 79s in _plan_cp_load_back_owner_lane_evictions (the [HiCache-load]
slow-scan) and was killed by the detokenizer health-check. Root cause (verified from the b300
hang log + code): the L1 free-room watermark (--hicache-l1-free-room-ratio 0.25 over a 31507-page
lane) hands the planner a ~7877-page single-owner deficit; the planner then rescans all ~2000
evictable candidates once per victim (~195 iters), and for EACH candidate every iteration it
recomputes _cp_load_back_node_owner_page_counts -- which under the pooled shared-L2 path (no
page_owners on CpSharedL2NodeMetadata) takes the device-tensor fallback and does cp_size per-owner
.item() device->host syncs. That is ~195 * 2000 * 4 ~= 1.5M CUDA syncs on the synchronous load-back
admission path, blocking the scheduler for ~79s.
Fix (byte-identical victim selection, just fast):
- Memoize the owner-count histogram per planning call ({node.id: counts}); the counts are invariant
while node.value is fixed (the plan does not mutate values), so node.id is a safe key for the plan's
duration. Threaded explicitly to both call sites (planner loop + ancestor-unlock helper). Turns
O(victims*candidates) recomputes into O(distinct nodes).
- Replace the cp_size per-owner sum().item() loop with one bincount().tolist() device->host sync.
Net: ~79s -> ~1s; the eviction plan (victims, planned_freed) is unchanged. bincount == the per-owner
loop proven over 8000 random vectors incl. the (-1)%cp==cp-1 zero-loc edge. New memo regression test;
existing count-fn + planner tests pass (the one pre-existing unrelated EAGLE-tail failure is unchanged).
(The 7877-page watermark magnitude is a separate, config-side issue: --hicache-l1-free-room-ratio 0.25
reserves ~25% of a ~2M-token lane -- ~30x more than a 64K chunk needs; lower it.)
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
On restart the LMDB index + disk-slab blobs persist, but CpL3Store.from_config built the slot
pools all-free and the GC LRU empty -> the next spill re-hands-out a slot the durable index still
references (clobbers a live blob) and GC never reclaims the carried-over entries. Neither a clean
start nor a durable reload was actually realized.
connect() now applies a cold-start policy BEFORE the bg threads start (the write thread is the sole
pool/GC owner, so the single-threaded reconcile must precede it):
- clear (default): wipe the persisted index + reset the pools/GC -> genuinely empty start (disk
blobs are inert, overwritten lazily on slot reuse).
- load: rebuild this rank's slot free-list + GC LRU from the durable disk blobs. Drive the scan
from the rank's OWN slab file (header-only reads) so it never inspects another rank's slots even
when ranks share a disk; a slot is LIVE iff its blob header parses AND the shared index still maps
that content hash back to this exact slot -> occupy + seed the GC LRU with the durable last_access;
orphan/unwritten slots stay free. Header-only (no payload CRC); reload-time verify-on-read still
fail-softs a torn payload. The L3 durable floor now survives a process restart.
Primitives: CpL3SlotPool.rebuild_from_allocated (O(num_slots) bulk-occupy) + CpL3DiskSlab.read_header
(one aligned block, not the multi-MB slot). Env SGLANG_CP_L3_COLD_START (default "clear"), read in
_maybe_init_cp_l3 and passed to connect(). Tests: 4 cold-start e2e (load rebuilds the floor + no slot
collision after a fresh spill; GC LRU rebuilt; clear starts empty; unknown mode fails loud) + 2 unit
(rebuild_from_allocated, read_header). 23 L3 store/disk/posix tests green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A radix split crashed: split_committed_object got split_pages=172 (from the node
KEY length) for a target_kv object of num_pages=1 (the host backup), raising
"split page count must leave at least one page on each side". Root cause: the L3
reload inserts a MALFORMED node -- _cp_l3_reserve_reloads stores the FULL n_full-
page suffix key but only the C L3-durable pages are reserved/hashed/host-backed
(C < n_full when L3 holds a partial durable prefix via page-level GC or partial
spill). The node then has len(key)//page = n_full but host_len//page =
object.num_pages = len(hash_value) = C, violating the radix invariant every
consumer assumes; the split derives split_pages from the long key and overruns the
C-page object. Pre-existing (L3 3.2, 864b1c808e); NOT the multi-slab change
(_allocate_contiguous raises on no-fit, never partial, so multi-slab cannot produce
a partial-backed node -- it crashes single-slab too).
Elegant fix -- restore the invariant at its single source: slice the reloaded node
to its C durable pages so len(key)//page == host_len//page == object.num_pages ==
len(hash_value) == C. The un-durable suffix [C:n_full] is a correct cache miss.
This makes _split_node / CpSharedL2NodeMetadata.split / split_committed_object / the
L3 page-set builders correct unchanged, and removes the latent negative-host_len and
value/hash mis-slice the same malformed node would have triggered.
- hiradix_cache.py _cp_l3_reserve_reloads: slice suffix_key to C pages (matching the
already-sliced suffix_hashes).
- hiradix_cache.py _cp_l3_build_owned_pages (spill) + _cp_l3_build_reload_owned_pages
(reload): fail loud if the page-hash count exceeds the object's pages (else a future
desync silently corrupts a neighbour object in the same slab -- the slab accessor
only catches a whole-slab overrun).
- hiradix_cache.py _split_node: assert split_len <= host_len (fail loud on any future
malformed partial-backed node instead of the cryptic split_pages>=num_pages).
- test_cp_shared_l2_pool.py: lock the split contract (split_committed_object rejects
split_pages outside (0,num_pages); metadata.split rejects object/padded mismatch).
Design + 3-agent investigation + 2-agent review (no bugs):
docs_internal/cp_hicache_l3_reload_partial_prefix_fix_design.md.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A single cudaHostRegister over a >~1 TB host buffer fails with
cudaErrorMemoryAllocation on B300 (hard per-call ceiling: 512 GiB OK, 1024 GiB
FAIL), crashing the hicache_size=1600 (~1.5 TB CP shared-L2 slab) prefill at
startup. The registration cannot simply be chunked: a memcpy (cudaMemcpyBatchAsync,
the CP-L2 H2D/D2H transfer) fails with cudaErrorInvalidValue when its host range
straddles a registration boundary (verified empirically on b300-049).
Fix: physically split the host cache into multiple page-aligned slabs, each <= a
safe single-registration size (default 480 GiB, env SGLANG_CP_HICACHE_MAX_SLAB_GB),
reusing the existing SharedHostTensorGroupAllocator + per-slab transfer splitting
(_host_transfer_segments). Each slab is one whole registration and no transfer
crosses a boundary; small configs (hicache_size<=400) stay single-slab unchanged.
- memory_pool_host.py: add cp_hicache_max_single_register_bytes() + the fail-loud
_check_single_cuda_host_register_size guard; revert the (transfer-unsafe)
registration chunking back to one cudaHostRegister per buffer/slab.
- hiradix_cache.py: _cp_shared_l2_slab_pages_by_payload auto-caps each payload's
slab <= the ceiling so large caches auto-split.
- cp_l3_slab_accessor.py: CpSharedL2SlabAccessor is now slab-count-aware
(CpL3SlabSpan + per-slab dispatch via global_base_page; per-slab layer stride);
_cp_l3_slab_spans rewires _maybe_init_cp_l3 off the single-slab assumption. L3
disk slabs / slot pool / LMDB index / GC are content-addressed and unchanged.
Tests: multi-slab accessor incl. a non-circular torch.frombuffer-layout check; a
real allocate_group + _cp_l3_slab_spans roundtrip; slab-cap auto-split; L3 store
cross-slab spill/reload. Reviewed by 3 adversarial agents, no correctness bugs.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The host-pool size check used psutil.virtual_memory().available -- regular RAM -- unconditionally. But
hugepages are carved OUT of regular RAM, so reserving e.g. 1 TB of 2M hugepages drops psutil.available
by ~1 TB, and the check then spuriously fails ("Not enough host memory ... only have 897 GB free") even
though the slab is allocated from the hugepages, not regular RAM. It was inspecting the wrong pool.
Two fixes:
- memory_pool_host.py: gate the psutil check on the DEFAULT (regular-malloc) allocator. A custom
host_tensor_allocator (the CP shared-L2 slab over hugetlbfs) owns its own capacity check, so skip the
regular-RAM check for it.
- cp_shared_l2_pool.py: add cp_shared_l2_hugetlbfs_free_bytes() + check_cp_shared_l2_hugetlbfs_capacity()
(statvfs the hugetlbfs mount: f_frsize = hugepage size, f_bavail = free hugepages) and call it in
create_cp_shared_host_slab before ftruncate/mmap. Now insufficient hugepages fail LOUD with a clean,
actionable message ("insufficient hugepages in /dev/hugepages: need X GB (N x 2M pages) but only Y GB
free; reserve more or reduce --hicache-size") instead of a cryptic mmap ENOMEM. Per-slab + sequential,
so each payload's slab sees the free remaining after the prior ones.
Unit-tested (capacity check: tiny fits, over-capacity fails loud). Pre-existing 2b L2-pooling code (not L3).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Under CP, enable_storage=False, so StorageMetricsCollector (prefetch/backup tokens + bandwidth) never
emits, and L2 pool usage was debug-log-only (_cp_maybe_log_lane_stats) while L3 was invisible. Add a
CpHiCacheMetricsCollector covering both, gated on enable_metrics alone, per-rank via the tp_rank label.
- CpL3Store.stats(): per-payload slot occupancy (used,total) + cumulative counters (spill_pages,
reload_pages, gc_reclaimed, write_errors -- incremented on the bg threads) + instantaneous inflight
(spill/reload) + the four bg queue depths. Counters are monotonic (NOT reset on clear()).
- CpHiCacheMetricsCollector (metrics_collector.py): gauges for instantaneous state
(sglang:cp_l2_used/total_pages, cp_l3_used/total_slots, cp_l3_inflight_*, cp_l3_queue_depth) +
counters for cumulative work (cp_l2_objects_committed/evicted_total, cp_l3_spill/reload_pages_total,
cp_l3_gc_reclaimed_total, cp_l3_write_errors_total). Counters fed via a monotonic .inc(delta) off the
store's cumulative totals.
- hiradix: create the collector in _maybe_init_cp_l3 (once, per-rank labels from cache_controller);
push periodically (~1s, per-rank wall-clock -- metrics need no rank-uniformity) from
check_hicache_events via _cp_maybe_collect_metrics, reading allocator.occupancy_by_payload()/stats()
+ store.stats(). Off the data path.
store.stats() unit-tested (occupancy + spill/reload counters; 10 store tests green). The collector +
wiring are correct-by-pattern (mirror StorageMetricsCollector) and validate on the live server (3.4;
prometheus_client not in the unit env). Directly useful for 3.4: watch L2/L3 fill + GC + reload hits
under cachebench.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Replaces §9.3's object-level rank-uniform eviction with per-rank, page-level LRU GC running ON THE
WRITE THREAD (the sole slot-pool owner -> no lock, no second owner). Genuinely communication-free:
each (hash,payload) is written/read/deleted by exactly its one owner (owner = i%cp_size, and the
prefix-chained content hash makes one-hash = one-position = one-owner), so the shared LMDB's own
consistency substitutes for collectives within L3 (design §9.5/§9.6). GC touches only L3, adds zero
collectives; the spill/reload MINs that remain are all the L2 bridge.
cp_l3_store.py:
- Per-payload lazy-deletion min-heap `_gc_heap` of (last_access, seq, hash) + authoritative
`_gc_current{hash->(last_access,slot)}`. Add on write, touch via `_touch_q`, reclaim coldest.
- The write loop, each iteration: drain touches -> _gc_collect (reclaim coldest of any pool over the
0.90 start watermark down to 0.85, bounded budget) BEFORE the next write, so spill never hits a full
pool (no evict burst on the critical path). Continuous + proactive, symmetric with the spill.
- Reclaim deletes the index entry (durable) BEFORE freeing the slot, so a racing reload reads None or a
CRC-mismatched reused slot -> miss -> recompute (fail-soft); no lock / in-flight-exclusion needed.
- submit_touch (scheduler->write thread); clear() resets the GC structures.
hiradix_cache.py: wire the reload `touch` (the 3.2 gap -- hit_count/last_access never updated): at
_cp_l3_admit_reload, bump the L3 last_access of THIS rank's owned reloaded pages (ALL pages, not just
the tail, so a prefix ages uniformly). _cp_l3_insert_reloaded_node now returns the node (its
last_access seeds the touch).
Sharing handled optimally for free (page = one entry, last_access = max over touchers; prefix pages
age together; shared-hot survives) -- no object-record table, no refcount, no content-keying. 56 L3
unit tests green (new: GC reclaims coldest-to-watermark + no slot leak; touch keeps a page warm).
Cold-rebuild (scan slab headers + LMDB) is designed (§9.6) but deferred to 3.4 (crash-recovery).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
On a radix miss, reload the evicted-but-L3-durable suffix from disk into L2 + insert a fresh
radix node, holding the triggering request until then (mirrors the storage-prefetch hold, which
is disabled under CP). The reloaded prefix re-enters the radix as a normal L2 node, so the
existing load_back serves L2->L1 -- no new device path.
Design (docs_internal/cp_hicache_l3_phase3_impl_design.md §9, refined for minimal sync):
- ENTRY (scheduler _prefetch_kvcache, enable_cp_l3 branch): mark a miss-with-suffix as a reload
candidate (rank-uniform: requests are broadcast). cp_l3_reload_lookup computes the suffix's
full-page content hashes -- the SAME SHA chain spill wrote (compute_node_hash_values).
- RESERVE + ADMIT fold into the existing per-tick _drain_l3_control_queues MINs -- ZERO new
collectives: the candidates' per-rank exists_prefix counts ride the qsize MIN vector -> a
rank-uniform agreed count C (this reconciles the async-LMDB read-skew); reload-ack oks ride the
durable ok-AND. Reserve is then collective-free (deterministic evict-to-fit mirroring
_reserve_write_cp_shared_l2_evict_to_fit); the request waits non-blocking in waiting_queue
(check_cp_l3_reload_progress skip) and is admitted + re-matched the SAME tick the reload lands
(check_hicache_events runs before batch formation). CP-aware insert only on a still-clean attach
(else abort+recompute). Capped (cp_l3_reload_max_inflight) + content-key deduped (piggyback).
EAGLE/bigram (opus-studied, PROVABLY correct -- not deferred): the radix key is bigram-converted
over the whole request, and convert_to_bigram_key(fill_ids[M:]) == bigrams(fill_ids)[M:] exactly
(the boundary bigram belongs to the matched prefix), so the bigram-converted suffix hashes
reproduce node.hash_value. Verified vs source + a new slice-identity regression test.
Opus review (FIX-THEN-SHIP, no CRITICAL; the 4 crash surfaces -- MIN-vector shape, read-skew,
attach-anchor, placement-digest -- traced clean) + independently re-verified; fixes folded:
- M1: cp_l3_release_request clears reload state on request abort/timeout/preempt (no leak).
- H1: rank-uniform per-op TTL bound releases a held request if its reload op never acks (the
default SGLANG_REQ_WAITING_TIMEOUT is off); the reservation frees safely at the (late) ack.
- L1: fail-soft anchor guard at insert (re-derive the first suffix hash from lhn's live hash).
- empty-waiters reload aborts (frees L2) instead of inserting an unrequested node.
Imports hoisted to top-level (get_hash_str -- hicache_storage is a leaf module, no cycle;
convert_to_bigram_key already top-level), no inline imports. py_compile clean; 54 L3 unit tests
green. Reload triggering (submit_reload/exists_prefix/free_object) now wired (was write-only).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The first 3.1 (d08ee9f8d) spilled the COLDEST resident objects and held the
protect_host eviction-pin through the entire slow disk write (released only at the
durable ack). Since the coldest objects ARE eviction's victims, a B300 cachebench
wire test wedged: evict-to-fit found everything pinned (evicted=0) ->
host_reservation_failed flood -> caching broke.
Redesign (docs_internal/cp_hicache_l3_phase3_impl_design.md §R3):
- cp_l3_store: split the single spill thread into a GATHER -> WRITE pipeline. Gather
copies each owned page off the pinned slab into a slab-independent anonymous-mmap
staging buffer (fast RAM memcpy) and acks GATHER; a separate write thread does the
O_DIRECT write + fdatasync + durable LMDB put off the staged copy and acks DURABLE.
The eviction-pin releases at the GATHER ack, so the object is evictable right after
the RAM copy; the disk write completes off the staged copy even if L2 reuses the
pages. Slab-full frees its partial slot allocation (no orphan) + acks ok=False.
- hiradix: continuous PROACTIVE spill — enqueue each just-committed object to a FIFO
deque at the replicated commit frontier (_commit_pending_backup) AND at radix splits
(the freshly-committed parent half), drained in commit order (not coldest). The deque
is capped (rank-uniform) so a disk stall can't OOM it. Spilling HOT just-committed
objects (disjoint from eviction's COLD victims) means the cold tail is already
L3-durable when evicted -> eviction just drops it, never contends for the pin.
- 3-element CP-group MIN drain [gather, durable, reload]: gather-MIN -> release_host;
durable-MIN -> l3_durable, gated by an ok-AND (a second MIN over per-op ok bits) so a
write failure on any rank means NO rank marks it durable (rank-uniform durability,
placement_digest stays green).
opus-reviewed (FIX-THEN-SHIP) + independently re-verified; review fixes folded:
split-enqueue (HIGH), deque cap for the disk-stall OOM (MED), fail-soft-on-write-failure
documented (HIGH; deliberately NOT re-enqueued — re-gather would churn under slab-full,
recompute is correctness-safe), rate-limited error logs (MED/LOW). 54 L3 unit tests
green (new: 2-phase gather-before-durable ordering, slab-full fail-soft + no slot leak).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Ties config -> per-rank disk slabs + slot pools + shared LMDB index + slab accessors. Background
spill/reload threads (off the scheduler tick, storage-template shape); object-granular acks (one per
object after all owned pages durable; zero-owned ranks ack in lockstep) via ack queues + has_inflight,
so the caller's CP-cpu-group MIN-drain frees the same objects on every rank. Spill = gather->O_DIRECT
write->durable index (data->fdatasync->index-commit ordering) with content-hash dedup; reload =
index lookup->read_into->scatter (verify-on-read). free_object frees owned slots+index (3.3 eviction
consumes); clear() is the flush_cache hook (stop/drain/reset/restart). from_config splits the disk
budget across ranks-on-disk x payloads (equal slot count). PLP gate at connect(). Model B: store is
content-addressed + rank-local I/O; only the LMDB is shared. End-to-end test (spill/exists/evict/reload
byte-exact/dedup/free/clear) 5/5 (venv lmdb). + accessor n_layers/page_num accessors.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
CpSharedL2SlabAccessor (HIGH-1): memcpy-gather a page's N_layers strided slab slices into a
contiguous buffer (spill) + scatter a contiguous blob back into the strided slices (reload) —
the cheap RAM bridge that lets host stay layer_page_first (inference perf) while disk is
page-contiguous. Generic CpL3SlabLayout(n_layers, page_num, slice_bytes) with verified-from-source
factories: for_mla (layer_num,page_num,page_size,kv_cache_dim,itemsize -> 2.74 MiB/page) and
for_index (n_active_layers,indexer_page_num,indexer_page_stride -> 0.17/0.63 MiB/page). gather_into/
scatter_from take an offset so the spill writes straight after the 64B slot header (zero extra copy).
Pure (mmap+ints), no torch. 8/8 tests. Canonical layer 0..N-1 order shared by spill+reload.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Preallocated disk-slab file per (payload_kind, drive); a page = one contiguous blob
(64B header + gathered payload + pad) in a 4K-aligned slot. O_DIRECT single-transfer
write/read (measured best vs vectored), buffered+fdatasync fallback for FS without O_DIRECT.
write_slot/read_slot convenience + write_aligned/read_into zero-copy (the QD>1 spill/reload
path gathers/scatters straight into the aligned slot buffer). verify-on-read: absent/torn/
foreign slot -> None (a MISS to recompute + reclaim), never a crash. posix_fallocate preallocate.
9/9 unit tests (real temp FS).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
CpL3Config (TOML/JSON): per-machine L3 disks (paths + budgets), backend, shared index
location/size, and the rank->disk mapping. disk_for_rank balances M CP ranks over N disks
(r % N; ranks share a disk gracefully — throughput is drive-count-bound) or honors an
explicit map; fail-loud on length/range mismatch. probe_disk_plp: O_DIRECT write+fdatasync
latency heuristic for the durability gate (non-PLP disk must fail loud when require_plp).
No hardcoded paths. 11/11 unit tests.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Phase 3.0 (L3 disk durable floor) foundational primitives, pure + unit-tested:
- 64B self-describing blob header (magic/version/payload-kind/content-hash/CRC),
verified on every read (verify_blob) -> torn/bit-rot slots become a MISS, not garbage.
- slot_bytes_for_page: header+payload rounded to the 4K O_DIRECT boundary.
- CpL3SlotPool: O(1) free-list over fixed-size per-payload disk page-slots (the L3
analog of CpSharedL2PageAllocator's free list), fail-loud on double-free/OOB, with
reset() for the flush_cache hook. NOT a ring buffer (eviction frees arbitrary slots).
Rank-local (a rank stores only its owned pages; L3 eviction selection rides the shared
LMDB replicated clock). 12/12 unit tests. Design: docs_internal/cp_hicache_l3_phase3_impl_design.md.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Replaces the interim ack_queue_len==0 band-aid with a structural fix so the perf skip is
SAFE rather than removed.
Root cause: the radix attach/defer/prune/split probes read `_node_host_write_pending`
(membership in ongoing_write_through/pending_host_backups, which are drained ASYNCHRONOUSLY
at per-rank ack completion), and `_cp_subtree_has_unprunable_state` also read the rank-local
`lock_ref`. So per-rank ack-drain timing leaked into the match_prefix truncation ->
cache_protected_len -> logical_len/len(value) -> the attach predicate. On some ranks the
prepared backup attached, on others it was dropped to the synchronous write_backup catch-up
(catch_up_all_layers draft=True), whose ack-append is per-rank. ack_write_queue then diverged
across CP ranks, so writing_check's ack_queue_len==0 early-return diverged: a strict subset
entered the writing_check_min all_reduce while the rest advanced to recv_requests' broadcast
on the same tp_cpu_group (8 ranks; dp_size==1 resets enable_dp_attention to False) -> NCCL
deadlock (prod hang: node_id=50713, all 8 GPUs 0% util).
Fix: introduce TreeNode.cp_backup_pending, a rank-replicated marker set at the rank-replicated
prepared-backup attach (_attach_prepared_cp_backup) and the guarded write_backup registration,
cleared only at the MIN-committed commit (_commit_pending_backup) / rollback. Rewire the CP
radix probes (_cp_node_split_still_pending, _split_node guard, _cp_subtree_has_unprunable_state,
_inc_hit_count) to read this marker instead of the drain-timed dicts, and DROP the lock_ref read
in the prune probe (its only cross-rank skew is the backup lock, now covered by the marker).
_node_host_write_pending stays the drain-timed accessor used only by writing_check / eviction /
the visibility check (_node_host_write_ready). With the radix-path reads replicated by
construction, len(value)==logical_len on every rank -> the prepared backup always attaches (or
rolls back) symmetrically -> the asymmetric catch-up never fires -> ack_write_queue is symmetric
-> the existing ack_queue_len==0 skip is all-or-none (no per-tick no-op MIN, best perf).
Correctness: the marker is cleared only at/after _commit_pending_backup, which runs only under
the MIN frontier, so the MIN remains the SOLE host-visibility gate (no KV-corruption class
reopened); the marker is strictly more conservative than the old dicts (stays True until commit).
Fail-fasts: double-attach raises; _split_node propagates the marker. hi_mamba unchanged (gates
on ongoing only, no async ack skip). Single-layer-draft (c3fc3ff752) preserved: the design
touches only the attach decision; the draft notifier already fires post-MoE.
Adds test_cp_hicache_symmetric_attach.py: the probes read the replicated marker not the dicts,
the prune probe ignores lock_ref, and the marker lifecycle (attach->commit->rollback) + the
double-attach guard. All pass on the fix; all fail on the pre-fix code.
Design: docs_internal/cp_hicache_symmetric_attach_design.md. Pending: ETE (GSM8K + no-hang
flood + TTFT) on the dev-cu13 container.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
(cherry picked from commit 876a98177cd749b5a63623ba2ae8b868289b8e59)
CP draft shared-KV target prefill only needs the CP-local draft hidden side channel until draft prefill consumes it. The reused ModelWorkerBatch was left with capture_draft_hidden_states enabled, and LogitsProcessorOutput retained the extra draft_hidden_states tensor past that point. Restore the capture flags after target prefill, disable draft-hidden capture for draft prefill, and drop the consumed reference.
Constraint: Large CP prefill batches are memory-sensitive; an extra hidden tensor held across the speculative step materially increases peak memory.
Rejected: Leave capture_draft_hidden_states sticky across draft prefill | it can capture or retain hidden state outside the target-side CP-local side channel.
Confidence: high
Scope-risk: narrow
Directive: Keep CP-local draft hidden as a target-prefill-only side channel unless the draft worker explicitly owns a new lifetime contract.
Tested: g0034 cjy-glm5-new PYTHONPATH=python python -m pytest -q test/registered/unit/mem_cache/test_cp_shared_kv_runtime.py::TestCpSharedKVRuntimeHelpers::test_token_slot_remap_cache_distinguishes_same_storage_views test/registered/unit/mem_cache/test_cp_shared_kv_runtime.py::TestCpSharedKVRuntimeHelpers::test_paged_slot_remap_cache_distinguishes_same_storage_views test/registered/unit/speculative/test_eagle_worker_v2_cp_hidden.py
Not-tested: full speculative integration/E2E workload.
(cherry picked from commit f31ef2293ce0cdda2359a5f4713996d78b47f9df)
The CP shared-KV remap caches may receive tensor views that share the same storage but represent different logical page rows. Keying only by storage pointer and shape can reuse a stale remap for another view, corrupting cache-hit materialization. Use the actual tensor data pointer plus stride, storage offset, and version so different views and mutations are not collapsed into one cache entry.
Constraint: CP shared-KV bs>1 cache-hit paths reuse small tensor views over shared backing tensors.
Rejected: Clear the remap cache on every call | would avoid aliasing but add avoidable hot-path churn and hide the identity bug.
Confidence: high
Scope-risk: narrow
Directive: Do not reduce the remap cache key back to storage pointer only; same-storage views are semantically distinct here.
Tested: g0034 cjy-glm5-new PYTHONPATH=python python -m pytest -q test/registered/unit/mem_cache/test_cp_shared_kv_runtime.py::TestCpSharedKVRuntimeHelpers::test_token_slot_remap_cache_distinguishes_same_storage_views test/registered/unit/mem_cache/test_cp_shared_kv_runtime.py::TestCpSharedKVRuntimeHelpers::test_paged_slot_remap_cache_distinguishes_same_storage_views test/registered/unit/speculative/test_eagle_worker_v2_cp_hidden.py
Not-tested: local pytest for CP runtime import is blocked by missing starlette in the local base environment.
(cherry picked from commit 7360ef13565dbf21428e3b121112135a2955f913)
Two latent CP shared-KV L2 correctness fixes, landed BEFORE L3 (not in an L3
commit). Surfaced by a per-CP8-instance (CP8DP2EP16) scoping review.
PREREQ-1 (CP-group scoping). The B1 commit/evict consensus collectives
(writing_check ReduceOp.MIN, placement_digest MIN/MAX + its tp_world_size<=1
entry guard, drain_storage_control_queues, the evict/prefetch MINs, the flush
barrier) AND cache_controller.prefetch_tp_group all derive from
self.tp_group/self.tp_world_size, which was params.tp_cache_group. tp_cache_group
equals the CP group ONLY at dp_size=1 (enable_dp_attention False -> tp_cpu_group,
and attn_cp_size==tp_size -> _ATTN_CP==_TP) -- the sole reason B1 works today.
Under CP8DP2 (DP attention, attn_tp_size=1) tp_cache_group is the size-1 attn-TP
group, so every `tp_world_size>1` collective silently no-ops per rank and the
placement assert self-disables -> divergent placement -> shared-slab corruption.
Fix: for CP hicache (cp_size>1) scope self.tp_group to the CP cpu group
(get_attention_cp_group().cpu_group -- already used for the slab-handle
broadcast) + self.tp_world_size to its size. A no-op handle change at dp_size=1
(same group object); the intended fix at CP8DP2. The single init-point change
propagates to every consensus collective + un-gates prefetch_tp_group + re-enables
the placement assert.
PREREQ-2 (flush reset). HiRadixCache.reset() cleared the radix tree + host pool
but never reset CpSharedL2PageAllocator -> stale free list/ranges/committed after
flush_cache (leak; the shared pool was never reclaimed). Added
CpSharedL2PageAllocator.reset() (rebuild the per-slab free list all-free, drop
ranges + committed, restore the freshly-built placement_digest) called from
cache_controller.reset() after the ack queues are cleared. Safe: flush_cache is
idle-gated (no in-flight backup/reserve). This is also L3's clear hookpoint.
Validation: new test_reset_restores_freshly_constructed_all_free_state + 89/89
pool suite (torch-2.11 container) + import smoke. PREREQ-1 is a no-op at dp_size=1
(live no-regression confirmed on the next prefill restart); CP8DP2 correctness is
by construction (CP-group membership verified) pending a 2-machine run.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Target-model skip-topk layers reuse the previous active layer's top-k indices and should not run local indexer modules. Centralize the layer-needs-indexer decision, skip constructing indexers on shared target layers, and skip their checkpoint tensors during load while keeping nextn/draft layers conservative for state safety.
Constraint: index skip should reduce GPU memory in both prefill and decode without changing top-k propagation semantics
Constraint: nextn/draft layers report shared top-k behavior but still need local indexer state safety
Rejected: Loader-only filtering | parameters are already allocated during model construction
Rejected: Dummy indexer modules for skipped layers | preserves most of the memory cost this change removes
Confidence: high
Scope-risk: moderate
Directive: Do not reintroduce indexer execution on skip_topk target layers without proving prev_topk propagation and weight residency semantics
Tested: remote g0034 cjy-glm5-new PYTHONPATH=python python -m pytest -q test/registered/unit/speculative/test_spec_utils.py test/registered/unit/configs/test_nsa_index_layers.py test/registered/unit/models/test_deepseek_index_skip_weight_loading.py -> 19 passed
Tested: remote g0034 cjy-glm5-new py_compile for modified runtime files
Not-tested: full GLM5 model restart memory delta measurement
EAGLE verification can pass torch scalar tensors through the speculative tree traversal before calling grammar backends. xgrammar/tvm_ffi requires Python int token ids, so normalize traversal indices and draft token ids at the boundary while leaving tensor storage unchanged.
Constraint: xgrammar/tvm_ffi rejects torch scalar tensors for GrammarMatcher.accept_token
Rejected: Coerce tokens inside every grammar backend | the invalid value originates in speculative traversal and should be fixed before backend dispatch
Confidence: high
Scope-risk: narrow
Directive: Keep grammar backend calls scalar-Python typed; do not pass torch scalar tensors through accept_token
Tested: remote g0034 cjy-glm5-new PYTHONPATH=python python -m pytest -q test/registered/unit/speculative/test_spec_utils.py test/registered/unit/configs/test_nsa_index_layers.py test/registered/unit/models/test_deepseek_index_skip_weight_loading.py -> 19 passed
Tested: remote g0034 cjy-glm5-new py_compile for modified runtime files
Not-tested: live decode replay after this commit
Tier-2-GC follow-on (design §9.12 flagged vestige). The metadata's `committed`
bool and `committed_payload_layers` dict were write-only residue of the option-A
quorum the GC removed: set at construction, validated in __post_init__, copied in
split() -- but their only content/True writer was the deleted
_commit_cp_shared_l2_layers_batched. Verified tree-wide there is NO live reader
(`committed` appears only in split's `committed=self.committed` copy;
`committed_payload_layers` only in __post_init__ validation + split copy +
construction). Commit consensus under B1 is the allocator's `_committed_objects`
(MIN frontier), so `metadata.committed` was a redundant second source of truth.
CORRECTION to the original flag: `required_payloads` is NOT a vestige -- it is
LIVE (read by cache_controller.load_cp_shared_l2, the evict path hiradix:2748,
and the readback payload planning). KEPT.
Removed: the 2 dataclass fields + their __post_init__ validation + the two split()
child-copies + the cache_controller reserve-construction kwargs + 4 test
constructions/assertions. No behavior change (fields were never read). Pool suite
88/88 (syh-dev-new/torch-2.11 env) + import smoke confirm the metadata dataclass is
now {logical_len, padded_len, page_size, object_ranges, required_payloads, object_key}.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Replaces the 2b.1b shared-L2 capacity-miss SKIP with a deterministic
collective-free evict-to-fit, and deletes the #5 deadlock. This is the gate that
makes --enable-cp-shared-physical-l2-hicache safe in a real run.
evict-to-fit (_reserve_write_cp_shared_l2_evict_to_fit, hiradix): on a shared-L2
reserve capacity miss -- which raises identically on every CP rank over the
replicated free list -- snapshot the plannable shared-L2 host leaves (excluding
the node being backed up) in the replicated SLRU order (_cp_host_evict_key =
Phase-1 logical clock + node.id total-order tiebreak), release the coldest one at
a time (each a replicated free-list mutation via the proven
_evict_cp_host_for_write_admission teardown -> evict_cp_host -> allocator.release)
and retry the pooled reserve after each, stopping at the first fit.
Fragmentation-correct (free coalesces in _return_range). Identical victim
set + order + deterministic reserve => every rank evicts the same victims and
stops at the same point (design Thm 1), so NO collective is needed. The snapshot
is one-level by design (a parent promoted to a leaf mid-loop is not re-pushed;
deep cascades skip-and-retry next tick -- missed identically on all ranks).
Exhaustion -> loud rate-limited skip (transient: pinned/in-flight objects hold
the pool), never a hang.
#5 deadlock DELETED: stripped the synchronize_across_ranks all_reduce machinery
(the `while len(heap) and not all_ranks_done()` ReduceOp.MIN host_evict_done_min
closure + the param) from _evict_host_for_physical_slots -- never reached (no
caller passed True) and the headline CP-deadlock shape. evict_host(num_tokens)
still works (single-arg, equivalent non-sync loop).
Opus adversarial review = SHIP (all 7 findings PASS: determinism [_cp_host_evict_key
purely replicated, pin_expiry dormant under CP], teardown byte-equivalence + no
double-free, no infinite recursion + clean abort-on-partial, snapshot safety [no
ancestor/descendant among host leaves], bounded termination, clean #5 strip,
flag-off path untouched). Tests: new test_eight_ranks_evict_to_fit_stays_identical
(fill->miss->release-in-order->retry -> identical placement, exercises coalescing)
+ 88/88 pool suite (syh-dev-new) + import smoke.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The 2b.1b adopt-then-strip left the entire option-A commit-quorum apparatus
orphaned: B1's writing_check ReduceOp.MIN frontier (mark_object_committed) is
the all-ranks-done consensus, so the per-(rank,layer,payload) gather quorum it
replaced is information-redundant (design sec 2.4 Corollary). This GC removes
the apparatus and collapses the CpSharedL2PageAllocator commit model to exactly
{_ranges_by_object, _committed_objects, _free_by_payload} -- precisely what
placement_digest() hashes -- so the cross-rank digest assert now covers the
whole model and the dead quorum is structurally unrepresentable.
Removed (all proven dead under B1, confirmed by a full tree caller-sweep +
opus adversarial review = SHIP):
- allocator: commit_layer, _has_full_commit, _expected_layers_for_object_payload,
adopt_reserved_range, set_object_required_payloads; fields _commits_by_object,
_expected_ranks, _adopted_ranges, _required_payloads_by_object,
_expected_layers_by_object, _required_payloads, _expected_layers; ctor args
expected_ranks/expected_layers/required_payloads; module fns
broadcast_cp_shared_l2_decision, gather_cp_shared_l2_{preflight,commits,commit}.
reserve/split_committed_object/_drop_object simplified to ranges+committed-bit.
- cache_controller: the 3 dead _commit_cp_shared_l2_* fns, 3 imports, all 5
option-A ctor params (cp_shared_l2_{cpu_group,source_rank,broadcast_fn,
preflight_fn,commit_fn}), the per-object commit-contract builder/setter/call.
- hiradix: allocator construction updated (3 args dropped); live _split_node
caller and _get_cp_shared_l2_rank_and_group@167 intact.
- tests: split tests migrated to mark_object_committed; 4 dead-symbol tests removed.
Lost __init__ payload-has-slab validation is covered by reserve()'s own
ValueError (fail-loud at first write). Default (flag-off) path unchanged: the
allocator is never constructed when enable_cp_shared_physical_l2_hicache=False.
Net -580 LOC. Validated: 87/87 pool suite (syh-dev-new, torch) + 31/31 core
classes locally + edited-module import smoke. Out of scope (flagged separately):
the CpSharedL2NodeMetadata.{required_payloads,committed_payload_layers} vestige.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The B1 write-through: every CP rank runs the IDENTICAL deterministic CpSharedL2PageAllocator.reserve over the replicated event stream -> identical placement with NO broadcast/gather; commit rides the writing_check ReduceOp.MIN frontier (mark_object_committed) instead of a per-(rank,layer,payload) gather quorum.
cache_controller.py: _reserve_write_cp_shared_l2 stripped to every-rank reserve (dropped preflight#2/rank0-gate/broadcast#3/adopt/missing-payloads; per-object contract kept MF3; idempotent abort-on-partial SF3); _submit_write_cp_layer_states drops the 3 gather-commit calls (per-layer D2H + all-payload done-gate MF1 + per-node ack kept); submit_write_cp_all_layer drops both fallback gathers (zero-owned keeps its ack MF2).
hiradix_cache.py: 3-way merge of l2_pooling shared-L2 init (clean, 0-conflict; Phase-1 clock + E1 + reserve-budget preserved) builds the allocator/slab when the flag is on and passes it to HiCacheController WITHOUT collective fns. The #5 deadlock removed: shared_l2_capacity reserve-miss now SKIPS the backup (reactive, rank-uniform) instead of _evict_host_for_physical_slots(synchronize_across_ranks=True) -- the deterministic shared-pool evict is 2b.2. mark_object_committed wired at _commit_pending_backup (the MIN commit). New _cp_assert_placement_replicated (SGLANG_CP_HICACHE_PLACEMENT_ASSERT) in check_hicache_events: MIN/MAX-reduce placement_digest across the CP group, fail-loud on divergence (Theorem 1 runtime gate; rank-uniform entry, cannot deadlock).
environ.py: SGLANG_CP_HICACHE_PLACEMENT_ASSERT (EnvBool, default off).
Tests: 8-rank reserve-determinism (identical placement across 8 ranks + divergence-detectable) + full pool suite 91/91 + import smoke on g0033 syh-dev-new. TWO opus adversarial reviews both SHIP (cache_controller strip + hiradix wiring).
NOTES: default-off (--enable-cp-shared-physical-l2-hicache); validated for write_through policy (prod default). Capacity-miss currently SKIPS (B1 shared-pool evict = 2b.2) so the flag must stay off in real runs until 2b.2. Dead gather island (3 fns + 3 imports, opus-confirmed inert) pending GC follow-up. Design+proof: docs_internal/cp_hicache_2b_pooled_l2_b1_design.md sec 2.4/9.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Add CpSharedL2PageAllocator.mark_object_committed(object_key) -- the B1 commit path that marks an object committed directly, bypassing the per-(rank,layer,payload) commit_layer/_has_full_commit quorum. Under B1 the all-ranks-done consensus is the writing_check ReduceOp.MIN frontier (the same barrier that releases the node write lock), so every rank calls this with the same object_key at the MIN commit point and the committed set transitions rank-uniformly (feeds placement_digest).
Resolves opus-review MF4: split_committed_object stays coherent for a B1-committed object (no per-layer commit facts) -- it adds children to _committed_objects and the empty _commits_by_object is harmless because B1 never calls _has_full_commit.
7 unit tests (pure-Python): commit-without-quorum, idempotent, unknown-raises, stat bump, digest reflects committed set + lockstep equality, split-of-marked-object coherent, release-after-mark frees pages. Full suite 88/88 green on g0033.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Add CpSharedL2PageAllocator.placement_digest() -- a deterministic, order-independent SHA-256 of the full replicated allocator state (free list + per-object ranges + committed set). This is the B1 proof-obligation gate from the 2b design (sec 2.4, Theorem 1): the write-through (2b.1) cross-rank assert hashes this each tick and EQ-checks it across CP ranks, turning placement-determinism into a fail-loud runtime invariant -- any reserve/release fired on a subset of ranks or with a per-rank arg changes the digest.
6 unit tests (pure-Python, no torch): determinism, changes-on-reserve, identical-op-sequence => identical-digest, divergent-op => different-digest, reserve+release restores digest (free-list coalescing), placement-order sensitivity. Full suite 81/81 green on g0033 syh-dev-new.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Adopt the ownerless shared-physical-L2 mechanics from origin/l2_pooling onto the Phase-1 branch, behind --enable-cp-shared-physical-l2-hicache (default off -> behavior-neutral). Foundation for the B1 collective-free allocator (2b.1/2b.2) and the L3 durable floor (Phase 3); no coordination yet.
- cp_shared_l2_pool.py (new): CpSharedL2PageAllocator (deterministic first-fit, capacity charged once, no x cp_size), hugetlbfs-2M slab primitives, position-indexed object ranges, commit-quorum data model.
- memory_pool_host.py: SharedHostTensor* slab orchestration (3-way merged; fix-output's net change to this file is blank-line-only -> additions-only, no content lost).
- server_args.py: flags + _handle_cp_shared_physical_l2_hicache_validation (3-way merged clean with Phase-1 assert + fix-output EnvField).
- test_cp_shared_l2_pool.py: 75 unit tests (allocator/slab/quorum), green on g0033 syh-dev-new; envs stub provides SGLANG_REQ_WAITING_TIMEOUT (read by Phase-1 validation).
Design + B1 proof: docs_internal/cp_hicache_2b_pooled_l2_b1_design.md (sec 2.4).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Make CP shared-KV HiCache eviction collective-free and scan-resistant by
removing every per-rank wall-clock input from the eviction/admission decisions
(any such input desyncs the must-be-replicated victim set / batch across the 8
CP ranks and can deadlock the collective-coupled writeback/load-back).
- Replicated logical clock: TreeNode.next_access_time() (a process-global
monotonic counter, mirrors mamba/swa's get_last_access_time) replaces
time.monotonic() as the source of last_access_time at every radix bump site
(radix_cache __init__/match/insert; hiradix CP match/insert/_insert_helper_host;
reset() zeroes it). creation_time/pin_expiry intentionally stay wall-clock.
Because match/insert events are replicated (reqs broadcast from rank 0 over the
replicated tree), last_access_time is now identical on every rank. Unique ints
also give a strict total order (no LRU tie ambiguity). No duration arithmetic
reads last_access_time, so non-CP LRU is unchanged; mamba/swa use their own
TreeNode and are untouched.
- CpReplicatedSLRUStrategy = (is_protected[hit>=2], last_access_time, node.id):
scan-resistant (cold one-shots stay probationary, evicted before reused/
protected prefixes), recency-within-segment ages out cold (not LFU), node.id
is the deterministic total-order tiebreak (heaps never compare TreeNodes).
Overridden for CP so it reaches every get_priority eviction site; the host
write-admission key _cp_host_evict_key is switched from FIFO-by-id to it.
- Co-fixes for the same per-rank-wall-clock class: pin_prefix is forbidden under
CP (its pin_expiry victim-eligibility check is per-rank wall-clock; SLRU
scan-resistance covers the benefit); the affinity head_age_s admission input is
disabled (=0.0, relying on the replicated head_defer_count bound); and a
server_args fail-fast guards CP shared-KV against SGLANG_REQ_WAITING_TIMEOUT>0
(its waiting-queue pruning is per-rank wall-clock).
Tests: test_evict_policy.py adds TestCpReplicatedSLRUStrategy (scan-resistance,
recency, total-order, full ordering) -- 30 passed in the dev-cu13 container;
test_radix_cache_unit.py adds logical-clock determinism/total-order tests.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A long cold-request workload flooded the prefill log (~177MB / 32K lines in
8min, all 8 CP ranks) with cp_host_reservation_plan_insufficient +
prepare_write_backup_reservation_failed even though the host pool was <42%
used and the writes physically fit.
Root cause: _free_room_deficit folds the proactive 20% free-room target
(hicache_host_free_room_ratio) into the admission deficit once a lane dips
below the 10% trigger. _evict_cp_host_for_write_admission then failed -- and
evicted nothing -- whenever it could not reclaim that full 20% target, which
is impossible while the residual is locked/pending. The lane never drained,
so every subsequent backup re-issued the same impossible demand and re-logged
on every tick. The reservation failure is itself a graceful skip, so there is
no crash; the symptom is the log storm.
Gate write-backup admission on the HARD deficit -- max(0, required-available)
over the target and draft lanes (draft_available is 2**62 with no draft pool,
a no-op) -- and evict toward the watermark best-effort, admitting whenever the
write itself fits. This drains the stuck lane and backs the request up instead
of skipping+flooding. The proactive watermark stays as the eviction target
(deficit_by_owner unchanged); it is no longer a hard admission gate. The
decision is computed from rank-replicated state on the collective-free reserve
path, so every CP rank makes the same admit/skip choice (opus-reviewed
rank-safe).
Also rate-limit the four host-reservation fallback warnings (once per 10s per
fallback_name, with a suppressed count) so any genuine exhaustion degrades
quietly instead of producing a log storm.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
CP shared-KV batch planning needs the immediately previous prepared batch to remain visible as a virtual prefix, but launching another batch before processing that result can leave multiple prepared plans racing against radix insertion. The event loop now processes the previous result after planning the current batch and before launching it, preserving one-batch lookback without accumulating deeper overlap state.
Constraint: CP HiCache prepared batch views are inserted during process_batch_result, not at forward launch.
Rejected: Process previous result before planning current batch | loses visibility of the previous pending prepared plan needed by current planning.
Confidence: medium
Scope-risk: moderate
Directive: Do not increase non-PP overlap depth for CP shared-KV without adding pending-radix reservation semantics.
Tested: Remote cjy-glm5-new pytest test/registered/unit/disaggregation/test_overlap_disagg_prefill_event_loop.py test/registered/unit/disaggregation/test_overlap_disagg_decode_event_loop.py
Not-tested: Full E2E latency impact of reduced overlap depth.
(cherry picked from commit 7df8723eee8203e9e334b229178e3f8bac61396a)
Under overlap scheduling a chunked request's final-chunk write-backup prepare
read a stale `is_chunked` (>0): that per-tick counter is decremented in
process_batch_result, which the overlap loop runs AFTER the run_batch prepare
hook. So prepare floored `backup_end` to a page boundary (the intermediate-chunk
rule) and dropped the now-complete final tail page, while the final non-chunked
insert builds the radix node at full unaligned length. The exact-equality attach
predicate (prepared.logical_len == len(value)) then failed by
(num_tokens-1) mod page_size, dropped the per-layer overlap backup, and forced
the serial all-layer catch-up (~89% of large chunked requests in prod).
Decouple the floor decision from the stale counter: the scheduler marks
`req.cp_backup_is_intermediate_chunk = (req is self.chunked_req)` in
`_prepare_hicache_write_backups_before_forward` (the live chunked_req identity
is the authoritative "will be chunked further" signal, set this tick before
run_batch), and the prepare candidate builder floors on that flag instead of
`is_chunked`. Intermediate chunks still floor; only the misclassified final
chunk now backs up its full tail and attaches the overlap backup.
Tests: update the chunked prepare test to the new flag; add a regression test
that a final chunk with stale is_chunked reserves the full tail; add an offline
repro that drives the real prepare/insert/probe and sweeps unaligned tails.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
serving_chat:
- Tolerate a malformed historical tool_call `arguments` string (a valid JSON
document followed by trailing content) instead of 400-ing the whole
multi-turn request: salvage the leading JSON document via raw_decode, else
keep the raw string. (A 112-message tool-history request was rejected with
orjson "unexpected content after document".)
- Catch TypeError (not only jinja2.TemplateError) from the chat-template
render so a `tojson` filter on a Jinja Undefined becomes a clean 400 instead
of a 500 (upstream #20700 / 5e9bd21979).
reasoning_parser:
- Strip only LEADING think-start marker tokens; a global replace would delete a
`<think>` token that legitimately appears inside reasoning content. Preserve
model-generated whitespace in reasoning/normal text (drop .strip()/.rstrip())
(upstream #24251 / dac78768f0).
- Add Glm45 detector tests: leading-only strip, token-inside-content preserved,
repeated leading markers, streaming trailing whitespace.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A bs=1 cache-hit prefill produced deterministically wrong output (e.g. "0.5,0.5,0.5").
Root cause: regression a24111a5f4 changed the bs=1 cache-hit call sites to pass
prefix_slot_spans=[] (get_or_build_batch_slot_spans want_prefix=False) together with
prefix_pages>0. In materialize_prefix_and_reuse_current_kv_page_slots and its index twin,
the guard `if prefix_slot_spans is not None:` let the empty list shadow the prefix_pages
fallback -> prefix_spans=[] -> the cached prefix dense slots were never materialized
(both IPC and local paths gate on `if prefix_spans:`) -> attention read zero KV over the
entire reused prefix. The indexer compose dropped its prefix the same way. bs=1 only;
bs>1 (non-empty per-request spans) and fresh prefill (no prefix) were unaffected.
Fix: make the canonical per-request slot-span list the sole description of the
prefix/current regions and fail loud on a missing list. Remove all four
span-reconstruction fallbacks: prefix_slot_span (singular, dead), prefix_pages->span
(the bug), current_slot_spans=None->span (dead), and the prefetcher's copy. Both twins
now require prefix_slot_spans + current_slot_spans (raise on None; [] = genuine
no-prefix). All call sites build canonical spans via want_prefix=True (cached per-forward,
so a24111a5f4's per-layer-CPU goal is preserved by the cache, not by skipping the build);
the MLA current-only path also uses want_prefix=True to keep want_prefix uniform and the
span cache thrash-free.
Tests: migrate unit tests off the removed prefix_pages param (drop it where spans were
already passed; supply canonical spans otherwise); fix two source-string/captured-kwarg
assertions; add test_materialize_prefix_requires_explicit_prefix_slot_spans (None->raise,
explicit spans -> non-zero prefix). test_cp_shared_kv_runtime.py: 158 passed on the
g0033 container.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Deferred non-chunked inserts can happen while a CP HiCache per-layer backup is still in flight. Rolling back the unattached prepared backup at unfinished-request time drops the only reservation that final insertion can attach, so cache_finished_req has to start a post-forward backup and catch up all layers synchronously.\n\nKeep the prepared backup for non-chunked deferred inserts and continue rolling it back for chunked middle inserts, where the suffix may be extended by later chunks and the old backup would cover the wrong range. Document the failure mode so future changes do not rediscover the same fallback path.\n\nConstraint: CP HiCache radix split cannot mutate in-flight backup nodes.\nConstraint: Chunked prefill middle inserts still need rollback because their backup range is not final.\nRejected: Always rollback unattached backups | causes post-forward catch_up_all_layers for non-chunked deferred inserts.\nRejected: Always preserve unattached backups | can attach stale backup ranges for chunked middle inserts.\nConfidence: high\nScope-risk: narrow\nDirective: Do not clear req.cp_hicache_prepared_backup on non-chunked deferred insert without proving final insert no longer needs it.\nTested: remote cjy-glm5-new py_compile radix_cache.py\nTested: remote cjy-glm5-new pytest test_cp_hicache_metadata.py::{nonchunked preserve,chunked rollback} => 2 passed\nNot-tested: live ETE replay after restarting prefill with this exact commit
Decode DP dispatch was collapsing onto a few ranks because the controller only randomizes among exact minimum load pairs. The load snapshot undercounted decode handoff work: pending prefill-info requests were absent, and DecodeRequest wrappers in prealloc/transfer queues were skipped because their rid lives on .req.
This makes scheduler load accounting unwrap DecodeRequest items and include pending decode requests, so TOTAL_TOKENS sees queued handoff backlog instead of repeatedly treating busy ranks as empty.
Constraint: Do not mask imbalance with synthetic per-request token penalties; dispatch should be driven by accurate observed load.
Rejected: Add req*4000 or other queue penalties | heuristic, workload-dependent, and hides the accounting bug.
Confidence: medium
Scope-risk: moderate
Directive: Any new decode handoff queue must be included in get_load() or DP routing can regress to stale/min-load collapse.
Tested: Remote cjy-glm5-new: PYTHONPATH=python python -m pytest -q test/registered/unit/observability/test_scheduler_metrics_load.py test/registered/unit/managers/test_prefill_adder.py -> 27 passed.
Not-tested: Fresh decode ETE distribution after service restart.
