scx_lavd: --per-cpu-dsq runtime error (invalid DSQ ID 0xfffffffffffffffe) #3067
Description
scx-scheds-git 1.0.18.r122.g68a37566-1
scx-tools-git 1:1.0.18.r5.gad8d7f5-1
2025-11-19T02:27:31.335335Z INFO ThreadId(01) scx_lavd: scheds/rust/scx_lavd/src/main.rs:314: Performance mode is enabled.
2025-11-19T02:27:31.335484Z INFO ThreadId(01) scx_lavd: scheds/rust/scx_lavd/src/main.rs:338: Energy model won't be used for CPU preference order.
2025-11-19T02:27:31.335503Z INFO ThreadId(01) scx_lavd: scheds/rust/scx_lavd/src/main.rs:967: Opts {
verbose: 0,
autopilot: false,
autopower: false,
performance: true,
powersave: false,
balanced: false,
slice_max_us: 5000,
slice_min_us: 500,
mig_delta_pct: 0,
pinned_slice_us: None,
preempt_shift: 5,
cpu_pref_order: "",
no_use_em: true,
no_futex_boost: false,
no_preemption: false,
no_wake_sync: false,
no_slice_boost: false,
per_cpu_dsq: true,
enable_cpu_bw: false,
no_core_compaction: true,
no_freq_scaling: false,
stats: None,
monitor: None,
monitor_sched_samples: None,
log_level: "info",
version: false,
run_id: None,
help_stats: false,
libbpf: LibbpfOpts {
relaxed_maps: None,
pin_root_path: None,
kconfig: None,
btf_custom_path: None,
bpf_token_path: None,
},
topology: None,
}
2025-11-19T02:27:33.260827Z INFO ThreadId(01) scx_lavd: scheds/rust/scx_lavd/src/main.rs:535: capacity bound: 597 (3.528369%)
primary CPUs: [12]
overflow CPUs: [13, 14, 15, 16, 17, 18, 19, 0, 1, 2, 3, 8, 9, 10, 11, 4, 5, 6, 7]
2025-11-19T02:27:33.260841Z INFO ThreadId(01) scx_lavd: scheds/rust/scx_lavd/src/main.rs:535: capacity bound: 16920 (100%)
primary CPUs: [4]
overflow CPUs: [6, 0, 2, 8, 10, 12, 13, 14, 15, 16, 17, 18, 19, 5, 7, 1, 3, 9, 11]
2025-11-19T02:27:35.232355Z WARN ThreadId(01) scx_utils::libbpf_logger: rust/scx_utils/src/libbpf_logger.rs:12: libbpf: map 'lavd_ops': BPF map skeleton link is uninitialized
2025-11-19T02:27:35.264179Z INFO ThreadId(01) scx_lavd: scheds/rust/scx_lavd/src/main.rs:1000: scx_lavd scheduler is initialized (build ID: 1.0.19-g68a37566 x86_64-unknown-linux-gnu)
2025-11-19T02:27:35.264189Z INFO ThreadId(01) scx_lavd: scheds/rust/scx_lavd/src/main.rs:1004: scx_lavd scheduler starts running.
DEBUG DUMP
================================================================================
swapper/8[0] triggered exit kind 1024:
runtime error (invalid DSQ ID 0xfffffffffffffffe)
Backtrace:
bpf_prog_b64e7ccbcad6e300_lavd_dispatch+0x6ac/0x85b
bpf__sched_ext_ops_dispatch+0x4b/0xa8
balance_one+0x1e4/0x11a0
balance_scx+0x35/0x190
__schedule+0x6c7/0x4590
do_idle+0x65a/0xac0
cpu_startup_entry+0x35/0x40
start_secondary+0x9a/0xa0
common_startup_64+0x13e/0x140
CPU states
----------
CPU 4 : nr_run=1 flags=0x9 cpu_rel=0 ops_qseq=86293 pnt_seq=15699
curr=scx_lavd[55780] class=ext_sched_class
*R scx_lavd[55780] +0ms
scx_state/flags=3/0x5 dsq_flags=0x0 ops_state/qseq=0/0
sticky/holding_cpu=-1/-1 dsq_id=(n/a)
dsq_vtime=0 slice=5492939 weight=100
cpus=fffff no_mig=0
Event counters
--------------
SCX_EV_SELECT_CPU_FALLBACK: 0
SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE: 0
SCX_EV_DISPATCH_KEEP_LAST: 0
SCX_EV_ENQ_SKIP_EXITING: 0
SCX_EV_ENQ_SKIP_MIGRATION_DISABLED: 0
SCX_EV_REFILL_SLICE_DFL: 0
SCX_EV_BYPASS_DURATION: 29331556
SCX_EV_BYPASS_DISPATCH: 0
SCX_EV_BYPASS_ACTIVATE: 1
================================================================================
2025-11-19T02:27:36.264556Z INFO ThreadId(01) scx_lavd: scheds/rust/scx_lavd/src/main.rs:899: Unregister scx_lavd scheduler
Error: EXIT: runtime error (invalid DSQ ID 0xfffffffffffffffe)
temporary workaround: Disable --per-cpu-dsq