Benchmarks And Comparison

This page consolidates the current implementation status, the latest measured C++ vs Rust benchmark results, and the latest firmware size snapshot.

At a glance

Area C++ firmware Rust ESP32-S3 port Current position
Shipping baseline Yes Default build is operational, but not full-feature-equivalent C++ remains the full-feature production baseline
Snapshot and command contract Full Full Parity validated
Hosted dashboard Full Full Parity validated
MQTT over TCP Full Full Parity validated
UDP discovery and room fusion Full Full Parity validated
OTA apply Full Partial Rust default build refuses HTTPS OTA explicitly unless https-ota is enabled
BLE observation Full Partial Rust scanner is feature-gated behind ble-scan and remains unstable on hardware

Latest device benchmark summary

Source: artifacts/ab-benchmark-latest.md, generated 2026-05-24T05:57:00.8327205Z.

Slice C++ per iter ns Rust per iter ns Winner Delta
parse_command_fixture 17831 674 Rust Rust faster by 26.46x
parse_room_config_fixture 122580 14296 Rust Rust faster by 8.57x
parse_tuning_config_fixture 96911 14815 Rust Rust faster by 6.54x
parse_generic_fixture 352801 63811 Rust Rust faster by 5.53x
derive_metrics_fixture 2623 1903 Rust Rust faster by 1.38x
detection_candidate_fixture 631 649 C++ C++ faster by 1.03x

Interpretation:

  • Rust won 5 of 6 measured slices in the latest device run.
  • C++ still holds a slight lead in detection_candidate_fixture.
  • The largest measured Rust gains are in command and config parsing.

Latest size snapshot

Source: artifacts/firmware-size-report.md, generated 2026-05-30T05:04:36Z.

Artifact Bytes KB
Rust ELF 1099212 1073.45
C++ BIN 1393568 1360.91
C++ ELF 3183436 3108.82

ELF section summary:

Artifact text data bss dec
Rust ELF 766865 11828 592068 1370761
C++ ELF 997170 412296 1029201 2438667

Runtime and stability notes

  • The decisive Rust stability improvement was switching the configured runtime from AP+STA coexistence to station-only.
  • The current stable Rust runtime also uses CpuClock::_80MHz and PowerSaveMode::Maximum.
  • SoftAP remains available for the unconfigured fallback path.
  • The stable Rust default build now also excludes https-ota and ble-scan, which brought the flashed app back down to the operational baseline footprint on COM17.
  • BLE scanning remains the main live-runtime gap on the Rust board.
  • OTA parity is now isolated to the opt-in https-ota slice, but that slice still failed to rejoin the LAN during the latest live COM17 validation.

How to reproduce

Collect the current device A/B benchmark report:

& '.\scripts\collect-ab-benchmarks.ps1'

Generate the current firmware size report:

npm run report:firmware-sizes

Run the Rust host benchmark directly:

& 'C:\Users\jd\.cargo\bin\cargo.exe' bench --manifest-path rust/crates/espwaverider-core/Cargo.toml --bench parity_bench

Read this with the parity matrix

This page summarizes performance and size. It is not the source of truth for feature completeness.

Use Parity Matrix for behavior and validation status.

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