User-reported: replaying a captured session dispatched 44 single-slot jobs
onto a 22-slot host. Root cause traced through two layers:
- bug-1836: sim_reconcile_unaccounted_jobs() (the "Recorded-Decision
Reconciliation" backstop) force-applied any recorded DISPATCH decision
it found, with zero live capacity check. Added
sim_reconciled_alloc_fits_capacity(), reusing the same
sched_check_host_satisfy()/sched_check_shared_satisfy() admission checks
the live picker/allocator path already uses.
- bug-1838: even with that gate, reconciliation still preempted every
freshly-PEND job before the live picker/allocator got a turn each round
-- unnecessary now that scheduler-sim-live-allocation gave sim mode the
same real, capacity-checked picker/allocator threads normal mode uses.
Narrowed reconciliation's trigger back to JOB_IS_RUN-only (undoing a
2026-09-11 widening whose own justification no longer holds), so a
freshly-pushed job now always flows through the same live, verified
decision path as normal mode. Reconciliation now only ever fires for a
job already RUN from before the replay's own observation window --
the one case structurally invisible to the live picker.
Also logged (bug-1837, not fixed here, needs its own design decision):
sim_reconcile_unaccounted_jobs() calls a picker's on_dispatch() hook from
the driver thread instead of the allocator thread plugin.h documents it
belonging to -- currently inert since the only real picker plugin happens
to lock internally, but not contract-safe for a future lock-free one.
Fixing bug-1838 required re-examining every test exercising the old
PEND-inclusive trigger; several needed their fixtures corrected to
register a real worker (harmless before any capacity check existed), and
others needed their actual intent re-derived and their assertions
inverted or restated now that a PEND job is never eligible for
reconciliation. Dated correction notes added in place to the
scheduler-sim-eager-reconciliation spec, matching its own existing
2026-09-11 correction-note precedent.
Verified: full scheduler suite 85/85, independently re-confirmed by
running the four most affected binaries directly.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Rongsong Shen
94115b0024