# google/marl

A hybrid thread / fiber task scheduler written in C++ 11

Repository: https://github.com/google/marl
Canonical: https://ross.abutalabs.com/products/marl
Language: C++
License: Apache-2.0
License Family: permissive
Topics: threads, fibers, scheduler, task-scheduler, tasks, coroutine, coroutine-library, fiber-task-scheduler, task-runner, thread-pool
Archived: true
Last push: 2026-04-27T19:02:22+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 79, release rhythm 35, longevity 100
- inputs: {"age_days": 2556, "days_push": 128, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2000, forks 204 (observed 2026-08-28T04:06:04.288159+00:00)

## What it is
Marl is a hybrid thread/fiber task scheduler library written in C++11 that lets you run tasks across a fixed pool of hardware threads. It uses fibers so tasks can block without wasting threads, and it has no external dependencies.

## Use cases
- schedule many tasks across a fixed thread pool in C++
- run blocking tasks efficiently without spawning extra threads
- parallelize workloads with fibers and coroutines in C++11
- build a task runner for cross-platform C++ applications
- coordinate async tasks with events and wait groups
- compile a task scheduler to WebAssembly with Emscripten

## When to choose
- you need efficient blocking-friendly task scheduling in C++ with zero dependencies
- you want a lightweight, portable scheduler across desktop, mobile, and wasm targets
- your workload has many tasks that block and you want to keep hardware thread usage fixed

## When to avoid
- you need a general-purpose async I/O runtime or event loop rather than a task scheduler
- you are not writing C++ or need higher-level parallelism primitives built into the language
- you need GPU or distributed parallelism rather than single-process task scheduling

## Facets
- artifact type: library
- maturity: stable
- function: concurrency, scheduling
- domain: developer-tools, performance, cross-platform
- platform: cpp, windows, wasm, cross-platform
- tags: fibers, task-scheduler, thread-pool, coroutines, c++11, parallelism, linux, macos, android, ios

## Member repositories
- google/marl (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:04.288159+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 2026-08-30T03:02:07.664633+00:00, confidence not recorded.
  - readme: https://github.com/google/marl (fetched 2026-08-28T04:06:04.288159+00:00, sha 1ec20562b9f3)
- Data as of 2026-08-30T08:39:29.467469+00:00.