Files
homarr/docs/perf
Thomas Camlong 89f081538c Merge origin/dev into feat/phase1-perf-impl
The branch was 12 commits behind dev and GitHub reported it CONFLICTING, which is
why the real CI workflow had not run since 2026-08-10 - a conflicting PR has no
mergeable ref, so pull_request-triggered workflows are skipped. Only the
lightweight checks (semantic title, CodeQL, CodeRabbit) were still reporting,
which made the PR look green while nothing was actually being tested.

Three conflicts, all of them this branch's barrel-diet work meeting dev's new
What's Up Docker integration. In every case the branch's structure is kept and
WUD is absorbed into it rather than the reverse:

  integrations/base/creator.ts   keep the lazy loader map; add wud as
                                () => import(...) rather than dev's static import,
                                which would have undone the lazy creator
  integrations/src/index.ts      keep the slim barrel; re-export WudStats and
                                WudContainerUpdate as `export type`, which is
                                erased at build and so adds no runtime module
  widgets/src/index.tsx          stays deleted - this was the barrel that put
                                every widget in the initial client graph

Registering WUD in the slimmed structures then needed three more entries that the
merge could not infer: base/kind-map.ts (type-only kind -> class map),
widgets/src/import.ts (type-only WidgetImports map, both the import and the
member). Each was found by typecheck rather than guessed at.

Verified: 37/37 packages typecheck, 1866/1881 unit tests pass. The 3 failures are
home-assistant and pi-hole, both testcontainers-based; both pass 11/11 in
isolation and fail only under 150-file parallel load with the container's payload
half-initialised.
2026-08-13 18:40:08 +02:00
..

Homarr performance investigation

Measured work on Homarr's memory and rendering cost, split by subject. Every figure here comes from a run of scripts/benchmarks/stress-restore.mts against a restored real backup — 4 boards, 51 widgets, 11 integrations, driven through an actual login — not from a synthetic or empty container.

document subject
SERVER-MEMORY.md What the container's RAM is made of, and the changes that reduced it
CLIENT-PERFORMANCE.md Dashboard rendering cost in Chrome: DOM, fibers, images, paint
WIDGET-AUDIT.md All 50 widgets, one at a time, with a verdict and the evidence for each
REJECTED.md Ideas that were implemented and measured, then abandoned — with the numbers
METHODOLOGY.md The tools, and the measurement traps that produced wrong answers
NEXT-STEPS.md Handoff: what is unverified, what to do next, and the set for a clean PR

Headline result

Server RAM, merge-base 06724cfeb vs this branch, two alternated runs per side, reported as cgroup anonymous memory because that is what counts against a container limit and cannot be reclaimed:

stage before after change
peak 376.6 MiB 279.3 MiB −26%
boot idle 130.5 MiB 62.4 MiB −52%
after sign-in 247.4 MiB 142.9 MiB −42%
dashboard loaded 293.4 MiB 170.4 MiB −42%
4 tabs, 2 boards 366.5 MiB 258.2 MiB −30%
after 2 min idle soak 323.7 MiB 200.8 MiB −38%

No before/after range overlaps at any stage. The cost is +18% CPU (solid, non-overlapping).

The changes that did it, by ratio

change size effect
--max-semi-space-size=4 1 line −19% idle, −21% peak
preloadEntriesOnStart: false 1 line −52% anon at idle, 310 fewer files even at full load
Umami: stop fetching 100k raw events per refresh 1 file −26% peak, −93% transient buffers
serverExternalPackages (mysql2/pg + 8 more) 1 block −21 MiB idle
ssh2's 16 MiB WASM heap (docker-modem patch) 1 patch −15 to −18 MiB external
content-visibility on media-release cards 4 lines −59% image requests, −41% layout objects

What is left, and why it is hard

One lever has real headroom and it pays twice. Roughly 41 MiB of retained bundle source and ~38 MiB of V8 compiler zone memory both scale with how much JavaScript the server loads and compiles, and the largest single contributor is a 16.10 MiB subtree reached by every API route — the tRPC router importing every integration eagerly. Reducing that reduces both.

Everything else has been measured and closed: see REJECTED.md.