Research note 01 / exploratory compute-HIL

Beyond DVFS: Queue-Stable Model-Tier Selection

When a fixed model cannot sustain a resource-constrained interval, changing the graph can preserve useful work that clock control alone cannot reach.

Nomos Research Nomos-TR-2026-01 Version 1.0 24 August 2026 7 pages Not peer reviewed

Abstract

Hardware clock scaling can reduce instantaneous power during onboard inference, but it cannot change a model's error profile or service demand. We screen three CloudScout width tiers at four frequencies on a Jetson Orin Nano, then compare static, scheduled, application-aware DVFS, and joint model/DVFS policies over a frozen 60-cell matrix. A first controller scored well but chattered 24 times, so the matrix stopped. A separately frozen queue-stable revision reduced the same smoke to two transitions. Joint selection adds utility in 12 cells and ties in 48. Every gain requires high false-clear cost and near-saturation or overload. This is a sensitivity boundary and failure study, not statistical, spacecraft, or flight evidence.

Heatmap of Nomos minus adaptive-DVFS normalized utility over four traces, three workload levels, and five cost ratios. Positive cells appear only at high costs under near or over load.
Figure 3 from the paper. Zeroes are substantive nulls. The energy-shortfall trace is non-binding and exactly duplicates benign outcomes.

Evidence ledger

Measured frontier

Three dense CloudScout tiers at 306, 408, 510, and 612 MHz. Full is dominated. Medium and tiny remain non-dominated. The highest tested clock minimizes whole-board joules per tile for every tier.

Negative result

V1 completes all 320 smoke tasks but switches model 24 times during a 128-task disturbance. The full matrix is intentionally stopped and the failed controller remains immutable.

Frozen repair

V2 admits only service-stable actions when one exists, demotes immediately, and requires eight stable observations plus deadline slack before promotion. The smoke falls to two transitions.

Matrix

Four traces × three workloads × five cost ratios × four policies. That is 240 policy runs, 76,800 task events, and 67,736 real adapted TensorRT engine calls.

Integrity

Zero TensorRT decision mismatches against sealed references, zero profile-based safety violations, and no answer key on the Jetson during hardware execution.

What this does not prove

Not a spacecraft trace

The resource traces and one-node thermal plant are synthetic. No operator bus trace, attitude history, calibrated thermal model, or FDIR interaction is present.

Not physical per-task DVFS

Every engine executes at 612 MHz. Lower-frequency actions replay a frozen one-repetition Orin profile table while still invoking the selected real engine.

Not statistical evidence

All 60 scenario cells reuse the same 320-tile shard. The 12/48/0 count maps a deterministic boundary and carries no confidence interval.

Subsequent evidence / Nomos-TR-2026-02

The frozen controller result now has a separate physical ground-validation companion.

Two EuroSAT model tiers were trained and measured on the Orin, exposing a real accuracy-energy frontier and a stock-governor cadence effect. Version 1.0 of this paper and its checksum remain unchanged.

Read note 02 →

Paper and artifacts

Cite

@techreport{nomos2026beyonddvfs,
  author      = {{Nomos Research}},
  title       = {Beyond DVFS: Queue-Stable Model-Tier Selection for
                 Resource-Constrained Onboard Inference},
  institution = {Nomos Research},
  number      = {Nomos-TR-2026-01},
  year        = {2026},
  url         = {https://nomos.run/research/beyond-dvfs/}
}