evm-gasfit 0.0.1

Estimate worst-case EVM gas costs from runtime measurements.

evm-gasfit

Estimate worst-case EVM gas costs from runtime measurements.

evm-gasfit is a standalone, analysis-only Python package. Given a YAML test config, a CSV of per-client runtime measurements, and a JSON of opcode counts, it fits NNLS regressions over the runtimes, applies an optional glue-opcode adjustment, and produces a gas-cost proposal as CSV and Markdown artifacts.

Install

For development (editable + test tools):

pip install -e ".[dev]"

The optional specs extra pulls per-fork GasCosts tables directly from ethereum/execution-specs. Without it, the package falls back to a bundled per-fork table:

pip install -e ".[specs]"

Python 3.10 or newer is required.

Quickstart

A minimal tests.yaml:

version: 1
anchor_rate: 1.0e8
clients:
  - geth
  - besu
gas_costs:
  fork: osaka
models:
  presets:
    - arithmetic_add

clients is required: only rows whose client_name matches an entry here are kept from the runtimes CSV, and a configured client that produced no fits at all surfaces in the proposal report's Incomplete client coverage section.

Any gas-param name that the model proposes but the fork's GasCosts doesn't already define must be declared up front under new_params. The value is either null ("no prior default") or an integer that renders as the current_gas baseline in the proposal diff:

new_params:
  COLD_ACCOUNT_NOCODE_ACCESS: null   # no prior default to diff against
  STORAGE_WRITE: 2800                # render 2800 in the diff column

Names without a declaration are a hard config error — this catches typos in model_params RHS values at load time.

Run the full pipeline from the command line:

evm-gasfit run \
    --config tests.yaml \
    --runtimes runtime.csv \
    --opcounts opcounts.json \
    --out ./out

Exit codes: 0 on success, 1 for config/input errors, 2 for modeling failures.

Or drive it from Python:

from evm_gasfit import GasFit

fit = GasFit.from_config("tests.yaml")
fit.load_runtimes("runtime.csv")
fit.load_opcounts("opcounts.json")
fit.estimate_models()
fit.build_proposal()
fit.write_reports("./out")

Public API

The top-level package re-exports a small surface:

from evm_gasfit import GasFit, GasCosts, load_config

Everything else is internal. See the rendered API reference at docs/api.md (auto-deployed to GitHub Pages from mkdocs.yml).

Outputs

write_reports(out_dir) emits:

• results.csv — one row per fit ((spec, model_by-combo, client)).
• new_gas_all_params.csv — per-client gas-param proposals.
• new_gas.csv — worst-case across clients (one row per gas param).
• runtime_estimation_autogenerated_report.md — per-spec regression summary.
• new_gas_proposal.md — final proposal, opening with a Contents TOC. Carries a diff table for fitted rows (against patched fork values + new_params integer baselines), a Client comparison section showing each parameter's worst vs. second-worst client and a worst / second-worst ratio (large ratios flag the worst client as an outlier) plus a per-client overview of proposed values — rendered as a log2(proposed / current) heatmap when plots are on (red = more expensive than current, green = cheaper, blank rows for new_params declared without a baseline) or as a markdown table when plots are off, a Worst-case provenance section with one collapsible block per gas param showing every per-client candidate (one row per (test_name, target_opcode, model_coef_name, model_by) combo, one column per client, cells = proposed gas); the cell the per-client selector picked as that client's worst-case is highlighted (outlined on the heatmap, bolded in the markdown-table fallback), and a warnings section containing Missing parameters (proposed names that produced no value), Incomplete client coverage (proposed names fit for some clients but missing on others), Missing glue adjustments, and Other. A trailing Poor-fit selections section flags winning fits whose p-value or R² crossed the modeling.poor_fit_*_threshold knobs (Winners with poor fit) plus any losing candidates that failed the same thresholds (Other weak candidates).

When glue adjustment is enabled, glue_results.csv, glue_opcodes_by_test.csv, and glue_opcodes_autogenerated_report.md are written too. Each priced glue opcode's per-client contribution is applied only when its fit passes both glue_contribution_p_value_threshold (default 0.05) and glue_contribution_rsquared_threshold (default 0.7); skipped contributions surface under Missing glue adjustments in the proposal so the affected gas params and clients are auditable. When output.plots: true, regression and diagnostic figures land under figs/.

Tests

pytest

The end-to-end suite synthesizes its own inputs and exercises the public API and CLI; there are no fixtures to download.

License

See LICENSE.