# plasma-umass/coz

Coz: Causal Profiling

Repository: https://github.com/plasma-umass/coz
Canonical: https://ross.abutalabs.com/products/coz
Language: C
License: NOASSERTION
License Family: other
Topics: profiler, optimization, causal-inference, performance-analysis, performance-engineering
Last push: 2026-07-10T21:20:58+00:00

## Health v2 (maintenance only)
Score: 86/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 91, release rhythm 71, longevity 100
- inputs: {"age_days": 4667, "days_push": 54, "days_rel": 199, "gap_med": 22.0, "n_releases_24m": 3}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4532, forks 171 (observed 2026-08-28T04:08:53.000724+00:00)

## What it is
Coz is a causal profiler for native code written in C/C++ and Rust. It runs performance experiments to predict how optimizing specific lines of code would affect overall throughput or latency, revealing optimization opportunities that traditional profilers miss.

## Use cases
- find which lines of code are worth optimizing in a C++ program
- profile a Rust application for performance bottlenecks
- measure the potential speedup from optimizing a function before investing effort
- identify optimization targets in parallel and asynchronous programs
- compare causal profiling results against traditional sampling profilers

## When to choose
- you profile native C/C++/Rust code on Linux or macOS
- traditional profilers give misleading hotspots in concurrent or parallel code
- you want to know the expected throughput or latency impact of an optimization before doing it

## When to avoid
- you need to profile managed languages like Java, Python, or JavaScript
- you are on Windows or another unsupported platform
- you need a low-overhead always-on production profiler rather than an experimental tool

## Facets
- artifact type: cli-tool
- maturity: active
- function: benchmarking, monitoring, developer-tools
- domain: developer-tools, performance
- platform: cli
- tags: causal-profiling, profiler, performance-analysis, native-code, c-cpp-rust, command-line, linux, macos

## Member repositories
- plasma-umass/coz (main) score 86

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:53.000724+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:20:12.644447+00:00, confidence not recorded.
  - readme: https://github.com/plasma-umass/coz (fetched 2026-08-28T04:08:53.000724+00:00, sha e315db45c98f)
- Data as of 2026-08-30T08:39:29.467469+00:00.