v1.54.0

libxtc (1.54.0-1) unstable; urgency=medium

• MINOR release -- optional scheduling policies and continuous batching.
  Both are off unless configured with --enable-sched-policy; a default
  build exports the new functions as XTC_E_NOSYS stubs and keeps the
  scheduler hot path unchanged.
• NEW API (xtc_sched.h):
  • xtc_sched_policy_set / xtc_sched_get_stats: a lane policy chooses
    which ready lane runs next. The runtime keeps queues, task
    lifetimes and wakes, validates the choice, and forces service of
    any lane bypassed max_bypass times (bound: max_bypass + L
    selection opportunities, not wall time).
  • xtc_sched_continuous_set: built-in policy preferring ready batch
    lanes, with the same bound.
• NEW API (xtc_batch.h):
  • xtc_batch_create / _submit / _cancel / _resume / _close / _destroy
    / _get_stats: preallocated, owner-local continuous batching. One
    vector step per iteration; finished requests leave and waiting
    ones join at the next boundary. FCFS admission against fixed
    resource charges, exactly-once completion, DEADLK for mutation
    from callbacks, close -> run -> destroy -> fini lifecycle.
• FIX: PIDs are loop-relative and every standalone loop encodes
  loop_id 0. Arena groups, xtc_app_shutdown, supervisor restart and
  add_child, fsm join, and stop messages now resolve in the owner
  loop's table. Before this, arena discard and app shutdown could
  kill an unrelated proc with an equal PID on another standalone loop.
• FIX: clang kept thread-local addresses live across fiber stack
  switches, so a migratable fiber resuming on another carrier wrote
  the previous thread's current-proc slot (heap-use-after-free under
  clang ASan; gcc builds unaffected). Thread-locals touched after a
  switch now go through non-inlinable accessors.
• NEW: examples/12_continuous_batching and a checked static versus
  continuous benchmark; scheduling guide section with a tested snippet.
• TESTS: deterministic replay, six planted DST bugs (all caught on
  seed 1), pinned seeds, off/on build and dispatch-trace equivalence.
• No existing public struct changed size.

-- Greg Burd greg@burd.me Sat, 10 Oct 2026 23:30:00 -0400