peltier.io
Spot cooling for hot paths. A profile-guided optimization agent that only ships wins it can prove.
Peltier profiles real binaries and services, isolates hot paths, proposes optimizations, and accepts a change only when two independent bars are cleared:
- Behavioral equivalence — the change provably preserves behavior (upstream tests, byte-identical golden replay, differential fuzzing, sanitizers) or it is discarded.
- Statistical significance — the speedup's bootstrap 95% CI lower bound clears a threshold on trusted, calibrated hardware.
Everything else is commentary. A change without both is not a win; it is a ledger row explaining why not.
What it has actually done
Every number here carries its 95% confidence interval and its workload, and every one survived the gates above. These are not projections.
| Result | Verified |
|---|---|
| tokei (Rust) — three compounding class-5 algorithmic wins | +10.7%, +3.7%, +9.9%, each CI-significant |
| tokei — link-time optimization (class 1) | +10.4%, CI [+8.5%, +12.0%] |
| cJSON (C) — number-handling rewrite (class 5) | +8.85%, CI [+7.5%, +10.0%] |
| cJSON HTTP service — p50 latency under replayed load | +6.2%, CI [+5.8%, +7.2%] |
| comrak (Rust) — mimalloc allocator swap (class 2) | +4.6%, CI [+3.3%, +5.8%], human-ruled |
Across five phases and 34 ledger rows, with zero shipped false accepts — including two occasions where the pipeline itself over-accepted and the audit caught it before anything shipped, each becoming a permanent new gate.
The differentiator
Consultants sell surveys; compilers sell flags. Peltier sells verified deltas with the methodology attached — a stopwatch on pinned hardware, a proof of equivalence, and an ROI figure whose confidence interval you can quote to a hostile reviewer. That is the entire product, and this site is how it works.
Start with the thesis, or jump to a case study. To run this discipline on your own code from your own agent, see the peltier skill.