Power Profiling#

Goal: capture current, voltage, and energy alongside PMU data using a Joulescope, in addition to the normal cycle-count profile.

Setup#

A Joulescope JS110 or JS220 wired in series with the EVB (pyjoulescope_driver ships as a core dependency — see Installation for udev/USB setup).

hpx_power.yml

model:
  path: my_model.tflite
  arena_size: 131072

engine:
  type: helia-rt
  config:
    variant: release-with-logs
    dist_path: path/to/helia_rt_v1_7_0

target:
  board: apollo510_evb

profiling:
  pmu_counters:
    cpu: all
  per_layer: true
  iterations: 5
  warmup: 2

power:
  enabled: true
  driver: joulescope          # auto-detects JS110 or JS220
  mode: external
  duration_s: 30

output:
  format: csv
  dir: ./results/power_run
  detailed: true

Run#

hpx profile --config hpx_power.yml

The profiler runs the normal PMU passes, then power-cycles the EVB and captures current/voltage for duration_s seconds during a clean, uninstrumented inference window.

What you get#

  Power:
    avg_current:  12.345 mA
    avg_power:    22.221 mW
    peak_current: 45.678 mA
    energy:       666.630 µJ

summary.json gets a matching power section (avg_current_a, avg_power_w, peak_current_a, energy_j), and --detailed adds detailed/power_summary.csv.

Comparing engines

Run the same power config with different engines to compare energy efficiency — see Engine Comparison.

Where to go deeper#

Power Measurement — wiring, sync GPIO, dedicated power firmware, window sizing, and troubleshooting a bad capture.
Output & Results — every result file and field.