docs: log bug-1931/1932, init parjob-capacity-partitioning spec
- bug-1931: the parjob allocator ignores minTasks (a tasks 2..5 job pends although 2 slots are free). - bug-1932: the unsatisfiable-request cache drops pend reasons on a hit and is unused in the simulator. - .kiro/specs/parjob-capacity-partitioning: initialized spec with the candidate heuristics for capacity-driven plan generation. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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"record": ".wolf/bugs/bug-1930.md",
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"gitea_issue": 355,
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"gitea_synced_status": "fixed"
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},
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{
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"id": "bug-1931",
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"status": "open",
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"status_updated": "2026-10-09",
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"status_note": "newly logged",
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"component": "scheduler",
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"severity": "wrong-result",
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"timestamp": "2026-10-09T07:23:49Z",
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"last_seen": "2026-10-09T07:23:49Z",
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"occurrences": 1,
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"error_message": "xce_scheduler parjob allocator ignores minTasks: a tasks 2..5 job pends though 2 slots are free\n\n**Observed:** in a `xce_scheduler --sim` session, element `[5]` of an array job requesting `tasks 2..5` pends although its only candidate host, pc13v, has 2 free slots (22 total, 20 in use by elements [1]-[4], 5 tasks each). The decision trace shows that only 5-task partitions are tried:\n```\n[trace] job 0-5-1791529946-0[5] session 23 position 5 level full\n requirement single tasks 2..5 requests mem=409600.000000 (400.00 KB)\n plan 1 hosts 1 tasks per position [5]\n host pc13v rejected (per-host check): resource shortfall\n slots total 22 in-use 20 reserved 0 requested 5\n plan 2 hosts 2 tasks per position [3, 2]\n host pc13v rejected (per-host check): resource shortfall\n slots total 22 in-use 20 reserved 0 requested 3\n plan 3 hosts 3 tasks per position [2, 2, 1]\n host pc13v accepted\n ...\n plans: 5 generated, 5 tried, 0 discarded, 0 not tried; no plan could be placed\n outcome: PEND\n host pc13v: resource slots: NO_RESOURCE\n```\n**Expected:** a job with `minTasks=2, maxTasks=5` is placed with any task count in 2..5 that fits, preferring the largest; here 2 tasks on pc13v (plan `[2]`). If even `minTasks` tasks cannot be placed, the job pends.\n**Impact:** every parallel job submitted with a task range (`minTasks < maxTasks`) is scheduled as if `minTasks == maxTasks`: it pends until `maxTasks` tasks fit, wasting free capacity and delaying the job indefinitely on a busy cluster. Wrong scheduling result, no crash.\n**Found by:** user review of the sim decision trace (2026-10-09).",
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"file": "src/scheduler/src/plugins/parjob_allocator.c, src/scheduler/src/alloc_runner.c",
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"root_cause": "TODO: required for fixed/partial",
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"fix": "TODO: required for fixed/partial\n\nVerification:\n- Test: TODO: name + file; RED before the fix, GREEN after\n- Suites: TODO: suite results and build profile\n- Live: TODO: soak/deploy run, or n/a and why",
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"tags": [
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"scheduler",
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"parjob",
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"allocation",
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"mintasks"
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],
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"related_bugs": [],
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"fix_commits": [],
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"record": ".wolf/bugs/bug-1931.md"
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},
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{
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"id": "bug-1932",
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"status": "open",
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"status_updated": "2026-10-09",
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"status_note": "newly logged",
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"component": "scheduler",
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"severity": "wrong-result",
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"timestamp": "2026-10-09T07:23:52Z",
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"last_seen": "2026-10-09T07:23:52Z",
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"occurrences": 1,
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"error_message": "xce_scheduler unsatisfiable-request cache drops pend reasons on a hit and is unused in sim\n\n**Observed:** in a `xce_scheduler --sim` session, array elements `[5]` and `[6]` have identical requests (`tasks 2..5`, mem 400 KB, same user/queue/project). `[5]` exhausts all 5 plans and pends; `[6]` then repeats the exact same search instead of reusing `[5]`'s verdict:\n```\n[sim] PEND jobid=0-5-1791529946-0[5]\n ...\n plans: 5 generated, 5 tried, 0 discarded, 0 not tried; no plan could be placed\n outcome: PEND\n main reason: none\n host pc13v: resource slots: NO_RESOURCE\n[sim] PEND jobid=0-5-1791529946-0[6]\n ... (same 5 plans, same host verdicts)\n plans: 5 generated, 5 tried, 0 discarded, 0 not tried; no plan could be placed\n```\n**Expected:** a request already proved unsatisfiable in this session pends at once, with the same pend reasons (main and per-host) the original attempt recorded, and the trace says it was skipped because of that earlier verdict. The live scheduler and the simulator should behave alike.\n**Impact:** the defect is in the normal (production) scheduler; the simulator's decision trace is what exposed it. Two defects in the session-level unsatisfiable-resreq cache (`alloc_cache.c`, scheduler-allocation Req 7):\n1. (normal scheduler, primary) see 2 below. (simulator) The simulator never registers the cache hooks (`main.c:527-528` registers them only in normal mode; `scheduler.c:247-256` treats NULL hooks as \"always compute fresh\"), so sim cost and sim decision traces differ from production: each identical pending element pays a full plan/host search.\n2. (normal scheduler) A cache hit reports only the stored main-reason category: `sched_pend_from_cached_reason_()` (`scheduler.c:173-184`) calls `add_job_preason(reasons, category, NULL, NULL)`, which erases host/resource reasons and sets `main_reason`. When the original attempt's main reason is 0 (\"none\") and its real cause is a per-host reason (as here: `pc13v: resource slots: NO_RESOURCE`), every later identical job pends with an empty reason, misleading operators (contrary to Req 7.5, \"report the same reason category\").\nWrong result (missing pend reasons) plus wasted scheduling time; no crash.\n**Found by:** user review of the sim decision trace (2026-10-09); defect 2 found by code review while investigating it.\n\nUPDATE (2026-10-09): per the user, the fix must cover the normal scheduler, not just the simulator: a cache hit must carry the original attempt's full pend reason (main, per-host and per-resource) in production, and the simulator must use the same cache so its traces match production.\n\nUPDATE (2026-10-09): production evidence already existed. `sim_verify.c`'s bug-1845 comment records a real captured `.replay` in which a live cache-hit PEND was recorded as `{main_reason=0, nhost_reasons=0, nres_reasons=0}` while the full computation for the same job gave `{main_reason=0, nres_reasons=2}`: the empty-reason hit of defect 2, on a real deployment.",
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"file": "src/scheduler/src/scheduler.c, src/scheduler/src/alloc_cache.c, src/scheduler/src/main.c",
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"root_cause": "Two separate gaps around the session-level unsatisfiable-resreq cache (`alloc_cache.c`, scheduler-allocation Req 7):\n\n1. **Only the main reason was cached.** `sched_make_primary_alloc_()` (`scheduler.c`) populated the cache with `ctx->reason->reasons->main_reason` (an `int`), and a hit went through `sched_pend_from_cached_reason_()`, i.e. `add_job_preason(reasons, category, NULL, NULL)`, whose main-reason branch erases the lists and sets only `main_reason`. The allocators record shortfalls as per-host/per-resource entries and leave `main_reason` at 0, so every hit pended its job with an entirely empty reason. Present since the cache was introduced (scheduler-allocation task 2.2/5.1); affects every normal-mode scheduler.\n2. **The simulator had no cache.** The table lived on `xce_scheduler_t` (`scheduler.h`), which a simulation core does not have, and the scheduler-sim-live-allocation spec made \"simulation isolation\" a non-goal: `sim_loop.c`/`sim.c` registered none of the hooks. So `xce_scheduler --sim` searched every identical pending job again, and its decision traces and pend reasons differed from production. This also forced the main-only `--sim-verify` PEND compare (bug-1845).",
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"fix": "- **Cache entries hold the full reason.** A cache value is now an owned entry (`cache_entry_t`, `alloc_cache.c`): a deep copy of the exhausted attempt's whole `xce_job_preason_t` (main, per-host, per-resource; strings `strdup`ed via `add_job_preason`, main reason first because that branch erases) plus the job id that proved it. The table's datakiller frees entries on clear/destroy; a failed `key_add` frees the rejected copy. `cache_lookup()` fills a caller-supplied reason; the scheduler looks up into a local and, only on a hit, moves it into `ctx->reason`, so a miss leaves `ctx->reason` exactly as before.\n- **The table lives on the core.** `xce_sched_core_t.unsatisfiable_cache` replaces `xce_scheduler_t.unsatisfiable_cache`; `cache_lookup/insert/clear` and the three hook adapters take `xce_sched_core_t*` with no cast to a driver struct (the round-1 cast is what once clobbered `alt_events_file`). `sched_init()` builds it, `cache_clear()` rebuilds it every session, `xce_sched_core_fini()` destroys it.\n- **Both drivers register the hooks.** `main.c` registers them on the live core as before and passes the same three adapters to the simulator through new `sched_sim_args_t` fields; `sched_sim_driver_start()` sets them on the simulation core (plain field writes, since white-box tests `#include` `sim.c` without `core_session.c`/`alloc_cache.c` and leave them NULL).\n- **Hook signatures** (`core.h`): lookup returns the reason and the source job id; populate takes the reason and job id. `sched_allocator()` (`sched_election.c`) sets `core->alloc_jobid` around `sched_make_allocation()` so the populate knows the job.\n- **Decision trace:** a hit adds a `NO_PLAN` entry with the new reason `XCE_TRACE_NOPLAN_KNOWN_UNSAT` and the source job (`sched_trace_known_unsat()`), rendered as `no plan generated: skipped, same request as <job> proved unsatisfiable earlier this session`; the outcome lines then show the restored reasons. `trace.h` stays at 796 lines.\n- `sim_verify.c` keeps its main-only PEND compare (old recordings still carry main-only hits, and a hit carries the proving job's reasons); its comment, `preason.h`'s, `core.h`'s and the scheduler-sim-live-allocation design.md (superseded note) were updated.\n\nVerification:\n- Test: TODO: name + file; RED before the fix, GREEN after\n- Suites: TODO: suite results and build profile\n- Live: TODO: soak/deploy run, or n/a and why",
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"tags": [
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"scheduler",
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"sim",
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"alloc-cache",
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"pend-reason"
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],
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"related_bugs": [],
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"fix_commits": [],
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"record": ".wolf/bugs/bug-1932.md"
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}
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]
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}
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