2 Commits

Include renames

Author	SHA1	Message	Date
samiandClaude Sonnet 5	322a20efa5	core: fix SegmentBudget over-admission and add a wait-list wakeup ... Root cause of the M7 RSS gap (core/docs/m7-baseline.md: ~70 MB measured against a 60 MB target): SegmentBudget::confirm_slot() only checked a task's own held count against its own target -- never the engine-wide active_ sum. reallocate_locked()'s two-pass fairness allocation does bound sum(target) <= max_active_ at the moment it computes a plan, but that bound says nothing about sum(held): a task can be legitimately holding more than its own just-lowered target for a while (yield is deferred to a segment boundary, never mid-segment -- ADR 0011 A1), and another task's target can correctly rise to claim that capacity before the first task has physically released it. Both confirm_slot() calls could then succeed against their own, individually-correct targets while sum(held) exceeded max_active_ -- tools/bench heap-profile caught this directly: budget.active reading 56-86 against a total of 32. confirm_slot() now also checks active_ < max_active_, unconditionally, as a backstop that doesn't depend on any task's target bookkeeping being in sync with what every other task holds. That creates a liveness question the original design never answered: a task denied only by this new check has a target that's already correct, so it never changes again and reallocate_locked()'s plain "fire a callback when a task's target changes" mechanism never revisits it. Task gained a waiting_for_slot flag, set on exactly this denial; release_slot()/deregister_task() (the only two places that free real capacity) now hand a freed slot directly to the highest-priority waiting task via wake_one_waiter_locked(), if reallocate_locked()'s own plan didn't already produce a callback for anyone. download_task.cpp's fill_slots_locked() needed a matching fix: a woken task's stalled segments (SegState::stalled -- backed off mid-retry, its own release_slot() already called) have no live worker and never surface through Segmenter::assign_slot(), which only hands out unassigned or fresh ranges. fill_slots_locked() now restarts any stalled segment with no live worker directly (bounded by slot_target, same as its assign_slot() loop) before looking for new work; a segment it doesn't get to keeps its own scheduled retry_worker() timer as a second chance. Also fixes a real TSan-caught data race this work surfaced: SegWorker:: speed_bps was written only by its own segment's curl callback and, before Progress.speed_bps's polled-path fix, only ever read from that same thread -- safe without synchronization. snapshot_progress() reading it from whatever thread calls DownloadHandle::progress() broke that invariant (workers_mu's shared_lock protects the workers map's structure, not an individual SegWorker's fields). Now std::atomic<double> with relaxed ordering -- an informational EMA, nothing synchronizes real state on it -- rather than adding a lock to the write side. core/tests/segment/budget_test.cpp adds two tests reproducing the actual gap (budget_active_never_exceeds_max_active_segments_under_concurrent_load, budget_wait_list_wakes_a_task_whose_target_never_changed) plus a sanity baseline (budget_release_wakes_a_denied_waiter), and introduces AsyncFakeTask + TestTimer for the one existing test that drives the budget from multiple concurrent threads -- mirroring production's real dispatch (register_task()'s on_target lambda posts through host.schedule(), download_task.cpp, never a synchronous call) rather than adding reentrancy-guarding machinery to SegmentBudget itself to compensate for a synchronous test double being unlike production. See docs/adr/0017 for the full writeup, including what an earlier version of this fix got wrong chasing a same-thread reentrancy hazard that doesn't actually exist in production. core/docs/m7-baseline.md updated: the RSS number now clears the DoD line (45.41 MiB via heap-profile), root-caused rather than just re-measured. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Q3QrF7rCt21bkAjt9BCDFQ	2026-09-12 10:58:14 +04:00
samiandClaude Sonnet 5	5d81b4cdae	core: segment/segmenter + segment/budget (stage 6) ... vdm/ids.hpp — TaskId, an opaque engine handle (DAEMON keeps the wire UUID <-> TaskId map; the engine never sees the UUID). segment/segmenter — per-download range management (docs/04 §3). Initial lazy split; assign_slot() splits the largest remaining range when the budget grants a slot; on_complete(may_steal) either *steals* the second half of the largest remaining range for the same worker (slot-neutral) or returns nullopt so the caller *yields* the slot (ADR 0011 A1); on_failed() returns requeue only on the 3rd consecutive connection error with a mirror present — the remaining range is orphaned and re-split. Non-resumable or unknown-size => exactly 1 segment; never split below min_segment_bytes (1 MiB). Resume ctor rebuilds from a persisted table (falls back to a fresh layout if it doesn't tile [0,total)). One mutex == "the task lock"; segment fields are std::atomic and the store is a std::deque so a steal's append never moves a worker's record. segment/budget — the global allocator (ADR 0011). Owns exactly one ceiling (maxActiveSegments) and min-1-before-seconds fairness: a two-pass allocation (guarantee pass gives every wanting task 1 slot in DAEMON's priority order, then a growth pass round-robins the rest up to each task's effective cap = min(per_task_cap, host cap, 1 if non-resumable)), recomputed from scratch on every edge so a live set_max_active_segments cut naturally yields the excess lowest-priority-first, never a mid-segment kill. DAEMON-facing surface exactly as promised in daemon/docs/core-requests-m1.md / ADR 0011: budget(), segments_active(), starved_tasks(), starved_since(), set_max_active_segments (drain), set_host_segment_cap, set_task_order, on_budget_changed (a jthread coalesces at <=4 Hz; the tasks_starved 0<->nonzero edge fires immediately). Callbacks are copied out and run after the lock is dropped. Tests: segmenter split/steal/requeue/resume math + a concurrent steal-and-advance run; budget min-1 under a tight budget, round-robin growth, host-cap and non-resumable clamps, live-lower shedding lowest-priority-first, starvation below the task count, starved-edge notification, and a concurrent set_want hammer. Green under ASan/UBSan; the steal path and the budget green under TSan. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01HPPSGhiArbvQgwC2DNiURS	2026-09-10 15:14:14 +04:00