Sync: host_build_graph early-dispatch up to current tensormap_and_ringbuffer#1335
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…gbuffer Follows PR hw-native-sys#1327 (which synced hbg's scheduler to tmr's hw-native-sys#1319 state). tmr then landed five more early-dispatch changes on the same subsystem; this ports them into host_build_graph's copies, preserving hbg's host-orchestration invariants (single ring, no execution-time reclaim, flat Runtime, no ACK-gate, host-side orchestrator). Absorbed from tmr: - hw-native-sys#1304 Add early-dispatch for require_sync_start SPMD cohorts, incl. the drain_stage_cores parallel-drain refactor (handle_drain_mode two-stage). - hw-native-sys#1326 Defer early dispatch until producer publication (correctness/race): published_block_count + record_published_blocks; propagate_dispatch_fanin is gated on published_block_count >= logical_block_num; the published_list ledger in dispatch and the stage_consumer_blocks two-sided publication/release handshake. - hw-native-sys#1328 Shrink dispatch cold-write cost via a folded-gate src_payload (PTO2DispatchPayload: not_ready -> volatile uint64_t src_payload, 0 = ready, non-zero = gated source PTO2TaskPayload address; global_context to the tail; the PTO2_TASKPAYLOAD_*_OFFSET constants + static_asserts). build_payload writes args on the ready path and only src_payload on the gated path; the idle AICore fills args[] from src_payload during its doorbell wait; init-time prefill of async_ctx slab pointers/capacity + context-ptr args; deferred_slab reset moved off the dispatch path; software-pipelined prefetch of the next block. - hw-native-sys#1329 Make early-dispatch doorbell ownership exclusive (correctness). - hw-native-sys#1331 Serialize block range claims (correctness): every block-range claim now goes through slot_state->claim_block_range(...) instead of an inline next_block_idx CAS. Preserved host-orch divergences (not overwritten by tmr): PTO2_MAX_RING_DEPTH==1 with rings[]/ring_id removed; no advance_ring_pointers / reset_for_reuse / check_and_handle_consumed (completion via completed_tasks_, consumer wait keys on fanout_refcount); flat runtime->workers / runtime->func_id_to_addr_ (not runtime->dev.*); pto_runtime2_types.h keeps its dropped pto2_dispatch_payload.h include; hbg's AICore FIN-vs-swimlane-record ordering and its no-ACK-gate completion path (drains via completion-before-dispatch + backstop flushes); no device orchestrator (orchestrator_done_ absent, scheduler threads gate on runtime_init_ready_). Out of scope (unrelated tmr changes hbg still lacks, tracked for a follow-up): per-device scheduler timeout (get_scheduler_timeout_ms), PTO2_TENSOR_DATA_TIMEOUT MS-vs-cycles (hw-native-sys#1189), stall sub-classification (hw-native-sys#1182), runtime scope_tasks_cap (hw-native-sys#1188). Verified: all 8 runtime targets build -Werror; a2a3sim host_build_graph scene suite 10/10; a2a3 onboard host_build_graph suite 10 passed / 1 skipped (paged_attention exercises the new claim_block_range serialization, drain_stage_cores drain, src_payload gated arg-fill, and published-block gating). tensormap_and_ringbuffer and the a5 runtimes are untouched.
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Code Review
This pull request optimizes the early-dispatch and sync-start paths in the runtime scheduler. Key changes include offloading argument vector materialization from the AICPU scheduler threads to the idle AICore when a task is gated, restructuring PTO2DispatchPayload to align hot writes to cache line 0, and prefilling constant fields once at initialization. Additionally, it introduces parallel staging in the sync-start drain mode to allow concurrent staging across scheduler threads, and implements a dedicated early_sync_start_queue with a rendezvous mechanism to ensure atomic launching of sync-start cohorts and prevent resource deadlocks. No review comments were provided, so there is no feedback to address.
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Summary
Follow-up to #1327. tmr landed five more early-dispatch changes on the shared scheduler; this ports them into
host_build_graph, preserving hbg's host-orchestration invariants.Absorbed: #1304 (require_sync_start SPMD early-dispatch +
drain_stage_cores), #1326 (defer early-dispatch until producer publication — race fix), #1328 (folded-gatesrc_payloadperf/ABI + AICore-side arg fill), #1329 (exclusive doorbell — fix), #1331 (serialize block-range claims viaclaim_block_range— fix).Preserved host-orch deltas: single-ring, no execution-time reclaim, flat
runtime->workers, droppedpto2_dispatch_payload.hinclude, AICore FIN/record order + no ACK-gate,runtime_init_ready_boot barrier.Out of scope (follow-up): per-device scheduler timeout,
PTO2_TENSOR_DATA_TIMEOUTMS (#1189), stall sub-classification (#1182), runtimescope_tasks_cap(#1188).Testing
-Werror