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>
Replaces sim_picker_thread_fn() (the always-PEND placeholder) with the
real sched_job_picker()/sched_allocator() threads (task 3.1), spawned
against &(sim->core) in sched_sim_driver_run(). Simulation mode now
genuinely uses the jbuf capacity-1 rendezvous for the first time
(confirmed still exactly one producer/one consumer). Adds
sched_election.c to sched_sim_isolation_lib.
Fixes bug-1829 (blocking, only reachable once sim_allocator() actually
called sched_make_allocation() for the first time): core->seqjob_
allocator/parjob_allocator were never bootstrapped for simulation mode
at all. Fixed via new sim_alloc.c (sim_bootstrap_seqjob_allocator()/
sim_bootstrap_parjob_allocator()), mirroring the sim_picker.c/
sim_limit.c precedent.
That fix's own workaround -- a throwaway xce_scheduler_t wrapper
satisfying seqjob/parjob's init_fn -- has a documented, narrow side
effect: prepare_allocation_hook fan-out during a live seqjob/parjob
dispatch attempt reaches the wrapper's own separate plugin registry,
not sim->core.plugins, so a plugin registered only against the real
sim core (the limit plugin) isn't reached for host-scoped matching
during a live dispatch yet. Documented in design.md's new "Known Seam
Gap" section; task 4.3 added to tasks.md to close it before task 5.2's
acceptance test can pass for the host-scoped case.
TDD: new end-to-end test drives a real .replay with an empty decisions
array (ruling out reconciliation) through the real thread pair,
proving a genuine DISPATCH from live resource availability. 25
pre-existing white-box sim/repl test files given link-satisfying
stubs reproducing the OLD always-PEND contract unchanged -- their own
assertions are untouched (task 5.3's job to reconcile deeper).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RLSNJhNoULvVcUhXEFafQC
info limit was correctly implemented and tested but inert against a real
replay: register_limit()'s only call site was normal-mode sched_register_
plugins(); sim mode's own plugin bootstrap (sim_bootstrap_picker()) never
registered the limit plugin. The snapshot format already carries the
original session's limit config (sim->core.config, a borrowed reference set
by xce_sched_core_load_snapshot()) -- nothing needed to change in the
recording/replay format.
New sim_bootstrap_limit_plugin() (sim_limit.c, mirroring sim_picker.c's
structure) registers the plugin via plugin_register_core() and seeds it via
a new limit_seed_config(plugin, xce_sched_core_t* core, config) entry point,
wired into sim_loop.c alongside the existing sim_bootstrap_picker() call.
limit_new_plugin() extracted from register_limit() as a factory, mirroring
builtin_fcfs_new_plugin()'s established pattern; register_limit() itself is
behavior-preserving.
First attempt set plugin->sched to a disguised xce_sched_sim_driver_t*,
relying on it sharing xce_scheduler_t's first-member layout to reuse the
existing config_hook path -- rejected on review: this repeats the exact
cross-cast pattern that already corrupted memory once in this codebase (see
core.h's xce_core_cache_clear_cb_t history). Fixed by making
limit_seed_config() take xce_sched_core_t* as an honest parameter instead,
with limit_update_config() (normal mode) and the new sim path both
delegating to a shared limit_seed_config_impl() -- no cast, no aliasing risk,
independently verified by two review rounds reading the actual struct
layouts and call chains.
Also added sim_limit.c to sched_sim_isolation_lib so Req 5 AC 17's
controller-I/O-isolation check covers it (an initial gap, closed in the same
remediation round). Two ripple waves of the same established link-stub
pattern applied to the ~24 white-box test files that #include sim_loop.c.
info limit now shows real configured-limit data against a genuine replay.
Live usage will still correctly show "no active usage instance yet" until a
separate, larger fix (logged as bug-1826) wires limit *matching* into the
sim decision path -- deliberately out of this task's scope.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RLSNJhNoULvVcUhXEFafQC
repl_info_limit() now displays accounted-usage/capacity for GLOBAL/SHARED
limit instances: iterates limit_get_usage_instances(), filters by
vres->limit == matched_limit, reads capacity from core.sharedInst[idx] and
accounted usage from core.sharedInUse[idx]. Existence-of-instance and
zero-usage are kept distinct per design.md: no matching instance (or one
with no populated capacity) prints "no active usage instance yet"; a
matched-but-never-charged instance correctly shows accounted=0 instead.
Self-caught during implementation and independently confirmed by review: a
negative or stale vres->idx (possible per add_vres()'s allocate-then-assign
pattern) is not safely rejected by zarray_get_ex()'s idx>=caps check alone
-- the new code adds an explicit idx<0 guard rather than copying
repl_info_resource_one()'s existing .count-based pre-check (which is itself
imprecise for a sparsely-populated zarray, a pre-existing issue left
out of scope here).
Calling limit_get_usage_instances() for the first time from repl_info.c
reproduced the same ~24-file link-stub ripple task 2.1 established for
limit_get_configured_limits() -- fixed with the identical pattern.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RLSNJhNoULvVcUhXEFafQC
repl_info_limit() (repl_info.c, not yet wired into repl_cmd_info() -- that's
task 4) resolves "all" vs a specific name against limit_get_configured_limits():
a NULL/empty handle on the all path reports "no limits configured" (Req 1.7);
a NULL handle or key_find() miss on the named path reports "no such limit
'<name>'" (Req 1.3) and never collapses into the all-only message. New
white-box test_repl_limit_table.c exercises both paths directly, including a
dedicated regression guard for the NULL-scoping rule.
Making repl_info.c genuinely call limit_get_configured_limits() broke the link
for ~24 other white-box test files that #include repl_info.c without also
linking plugins/limit.c -- fixed with the same link-satisfying-stub idiom this
file family already uses elsewhere (all return NULL, verified behavior-
preserving since none of these fixtures register the limit plugin).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RLSNJhNoULvVcUhXEFafQC
bug-1790's fix worked but put limit-plugin-specific logic in the wrong
place: seqjob_prepare_allocation()/parjob_prepare_allocation() (the
allocator plugins) unconditionally pre-computed a job-wide total for
every per-host resource in the job's rusages, "just in case" some
global limit needed one. That's the allocator plugins' concern leaking
into limit evaluation -- duplicated across both allocators (a third
would need it too), and wasteful (computed for resources no limit
actually references).
Moved ownership to sched_fill_limit_requests() (resource.c), called
once centrally from plugin_prepare_allocation() regardless of which
allocator ran:
- Removed calc_wanted_host_resval_job_totals() and its calls from both
allocator plugins entirely.
- Added calc_wanted_job_total_resval() (resreq.c): an on-demand,
single-resource lookup by name (no resmgr/key_find needed -- the
caller already has the resolved xce_resource_t), computing the same
job-wide-total formula only for the one (scope, underlying-resource)
combination that needs it -- a GLOBAL limit on a per-host resource.
The other three combinations are unchanged, still reading straight
out of alloc_req.
- sched_fill_limit_requests() gains rusages/nhosts/nslots parameters
back (a genuine need this time, not a re-added unused one).
plugin.c's two call sites pass obj->u.primary->resreq->rusages
(NULL for COMPOUND/ALTER, matching this codebase's existing scope
convention for those tags) and ctx->nhosts/ctx->nslots.
All 23 testsuite link-satisfying stubs mechanically updated. Removed
the two allocator-level regression tests from the first pass (the
behavior they proved no longer exists by design); rewrote
test_fill_limit_requests_global_limit_on_host_resource_reads_host to
exercise the new on-demand path directly, nslots=3 to prove the job's
WHOLE total is used.
Full xce-build.sh all asan --incremental: 94/94 Ok, zero regressions.
Live re-verified against the same ug1_global_mem deploy/scenario:
byte-identical scheduler trace to the pre-refactor result, confirming
behavior-preserving.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GLfB5uWRdmx2WiZSFC7Fm7
sched_fill_limit_requests() used to read a limit's underlying resource's
want from the same vector its own virtual-resource entry gets written to.
That's wrong whenever the two differ in scope -- e.g. a GLOBAL limit built
on top of a per-host resource like "slots" (limits.yaml's
ug1_normal_slots): the limit's own vres entry belongs in alloc_req->shared,
but "slots"'s want is only ever staged into alloc_req->host by
seqjob/parjob_prepare_allocation(), so the old code always read a zero and
silently never enforced the cap.
Now both the read source and write destination are derived independently
from each resource's own XCE_RESF_GLOBAL flag (vres->res for the source,
vres->vres for the destination) -- the same flag
calc_wanted_global_resvals()/calc_wanted_host_resvals() (resreq.c) already
dispatch on, so this is the existing rule applied consistently rather than
a new one. Also drops sched_fill_limit_requests()'s unused xce_scheduler_t*
parameter.
Full scheduler suite: 76/77 (the one failure, test_job_rusage_reconciles_
mem_reservation_against_usage, is bug-1762, pre-existing and unrelated).
Live-verified against a fresh single-node deploy.
Filed bug-1790 to track a known, deliberately out-of-scope residual gap:
a future global limit on a per-host resource other than "slots" would need
calc_wanted_host_resvals() to also run during the global phase for that
resource, which nothing currently does.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GLfB5uWRdmx2WiZSFC7Fm7
Adds 6 failing tests for the Event Echo Preamble Deduplicator
(Requirements 1.1-1.4, 2.2): a second echoed event sharing its
predecessor's rendered timestamp+session omits its preamble; two
events across a session boundary both print their own preamble; the
critical raw-vs-rendered nuance (Requirement 1.3) - two events whose
raw nanosecond timestamps genuinely differ but whose rendered,
second-granularity timestamp and session are identical still dedupe,
with a fixture-premise self-check proving the two raw values really
do render identically; the first echoed event in a fresh session
always prints its preamble; a structural event under continue mode
after suppressed routine events follows the same rule; event content
and ordering are unaffected regardless of the preamble decision.
Lands in a new test_repl_step_verbosity.c (1010 lines, 6 tests) rather
than extending test_repl_event_echo.c (705 lines) - proactive split
per this file family's established practice, since appending would
have pushed that file well past the project's ~1000-line trigger.
Registered in testsuite/meson.build. No production code touched.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YAWMhfRJFnmmnG8h97yUDd
