carlos / todomvc-bakeoff Public

docs: where you'd use each setup

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Paul Campbell pushed by claude 1 day ago 7c4ec8d52587a04441a041ded080d3016fc91084 parent 0ac20d3

2 files changed, +17 −0

docs/writeup.md +15 −0
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Whatever you pick, check the route to a static ARM executable first. A hard route costs more time and money even when the app's code is straightforward.

+## Where you'd use each

+|---|---|---|---|

+| **Go + Rastrillo** | Building a real CARLOS product: sessions, migrations, identity, the family's conventions | You need high write rates in a single instance | 336 reads/s, 309 writes/s; 10 s cold build, 0.1 s rebuild; the platform's own framework |

+| **Rust** | One instance takes heavy traffic, and you want a mature, production server stack | Fast edit-and-rebuild matters more than speed in production | 1,398 reads/s uncapped; 14 MB at rest; 3 MB binary; never failed under load; cheapest to build ($2.92) |

+| **Nim** | Footprint is everything: many busy tenants per box, tiny binaries | It's exposed to the internet and needs a hardened server (timeouts, keep-alive limits) | Top throughput (1,491 reads/s, 3,561 writes/s); 3.5 / 11.5 MB memory; 1.8 MB binary; patched stdlib server; 502s at 256 connections |

+| **Zig** | Same as Nim, with a C-like control over memory and almost no dependencies | You want a stable language to maintain for years (0.x; standard library APIs still change) | 1,382 reads/s, 3,113 writes/s; 2.5 MB at rest; 1.9 MB binary; an invalid-UTF-8 crash caught in review |

+| **Spinel** | Experiments, and Ruby developers curious about compiled Ruby | Anything in production yet | 722 reads/s; tiny memory (13 MB peak); but the process exited 16 times under load; whole-program rebuild of 104 s; the costliest build ($10.70) |

## What it means for Carloku

Mojo couldn't ship because its runtime comes only as shared libraries, which led to [Idea 360](https://amadan.net/carlos/platform/-/discussion/360): binary releases that carry their own shared libraries. Members can't empty or reset an instance's database, and deleting an instance parks its hostname until an operator purges it, which is [Feature Request 364](https://amadan.net/carlos/platform/-/discussion/364). Members also can't see an instance's memory use ([discussion 365](https://amadan.net/carlos/platform/-/discussion/365)).

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<p>Use Nim or Zig when memory, executable size and request rate matter. Both made executables under 2 MB, used a few megabytes at rest, and served about four times as many page loads as Go. The catch is maturity: Nim's builder had to patch a copy of the standard library's basic HTTP server to listen on a Unix socket, and that server has no request timeouts.</p>

<p>Use Rust when you want a mature server stack without giving much away. It runs axum on tokio, reached 1,398 page loads a second when the edge didn't intervene, used 14 MB at rest, and was the cheapest to build with AI.</p>

<p>Whatever you pick, check the route to a static ARM executable first. A hard route costs more time and money even when the app's code is straightforward.</p>

+<h2>Where you'd use each</h2>

+<div class="scroll"><table><tr><th>Setup</th><th>Use it when</th><th>Think twice when</th><th>From the bakeoff</th></tr><tr><td><strong>Go + Rastrillo</strong></td><td>Building a real CARLOS product: sessions, migrations, identity, the family's conventions</td><td>You need high write rates in a single instance</td><td>336 reads/s, 309 writes/s; 10 s cold build, 0.1 s rebuild; the platform's own framework</td></tr><tr><td><strong>Go</strong></td><td>You want CARLOS's defaults without a framework, or a small service or tool</td><td>You'd end up rebuilding what Rastrillo gives you</td><td>349 reads/s, 810 writes/s; same 10 s / 0.1 s builds; 1 dependency</td></tr><tr><td><strong>Rust</strong></td><td>One instance takes heavy traffic, and you want a mature, production server stack</td><td>Fast edit-and-rebuild matters more than speed in production</td><td>1,398 reads/s uncapped; 14 MB at rest; 3 MB binary; never failed under load; cheapest to build ($2.92)</td></tr><tr><td><strong>Nim</strong></td><td>Footprint is everything: many busy tenants per box, tiny binaries</td><td>It's exposed to the internet and needs a hardened server (timeouts, keep-alive limits)</td><td>Top throughput (1,491 reads/s, 3,561 writes/s); 3.5 / 11.5 MB memory; 1.8 MB binary; patched stdlib server; 502s at 256 connections</td></tr><tr><td><strong>Zig</strong></td><td>Same as Nim, with a C-like control over memory and almost no dependencies</td><td>You want a stable language to maintain for years (0.x; standard library APIs still change)</td><td>1,382 reads/s, 3,113 writes/s; 2.5 MB at rest; 1.9 MB binary; an invalid-UTF-8 crash caught in review</td></tr><tr><td><strong>OCaml</strong></td><td>Your team likes strong types and wants low, steady memory</td><td>You need native ARM builds without an emulator or a native ARM machine</td><td>992 reads/s; peak memory only 17 MB; 18-minute emulated cold build</td></tr><tr><td><strong>Haskell</strong></td><td>Your team already writes Haskell and values its type system</td><td>Build times and binary size matter</td><td>400 reads/s; 77 MB peak (the highest); 29 MB binary; 19-minute emulated cold build, 27 s rebuild</td></tr><tr><td><strong>Swift</strong></td><td>Your team writes Swift (say, sharing models with an iOS app)</td><td>Memory at rest matters (it had the highest)</td><td>537 reads/s, 1,453 writes/s; 24 MB at rest; 22 MB binary; 81 s cold build</td></tr><tr><td><strong>Spinel</strong></td><td>Experiments, and Ruby developers curious about compiled Ruby</td><td>Anything in production yet</td><td>722 reads/s; tiny memory (13 MB peak); but the process exited 16 times under load; whole-program rebuild of 104 s; the costliest build ($10.70)</td></tr><tr><td><strong>Mojo</strong></td><td>Not on Carloku today</td><td>—</td><td>Can't make a single self-contained binary; platform <a href="https://amadan.net/carlos/platform/-/discussion/360">Idea 360</a></td></tr></table></div>

<h2>What it means for Carloku</h2>

<p>Mojo couldn't ship because its runtime comes only as shared libraries, which led to <a href="https://amadan.net/carlos/platform/-/discussion/360">Idea 360</a>: binary releases that carry their own shared libraries. Members can't empty or reset an instance's database, and deleting an instance parks its hostname until an operator purges it, which is <a href="https://amadan.net/carlos/platform/-/discussion/364">Feature Request 364</a>. Members also can't see an instance's memory use (<a href="https://amadan.net/carlos/platform/-/discussion/365">discussion 365</a>).</p>

<p>Three smaller things came up. <code>carlos vet</code> is listed as a member command but needs operator access. The health column in <code>carlos instances list</code> lags by minutes, while the platform's own log events are accurate. And the edge's 64-request limit shapes any load test run from one machine. None of this stopped the apps from running, but it limits what members can measure and diagnose.</p>