Side-by-side substep timing (Update CI, same SHA, post cache-revert):
Mac Linux Windows
install uv 1s 1s 12s
uv pip install unsloth 8s 10s 29s
Node setup 4s 4s 35s <- winget reinstall
frontend build 20s 22s 204s <- 10x slower
9-step uv pip deps 15s 20s 92s <- 5x slower
llama.cpp validate 38s 21s 13s
-------------------------------------------------
total 96s 93s 400s
Two Windows-specific time sinks have nothing to do with the install
logic itself; they are runner-environment friction:
(1) `setup.ps1` line 1109-1145 requires Node 22.12+ AND npm >=11
(Vite 8 hard requirement). actions/setup-node@v4 with
`node-version: '22'` lands Node 22.22.2 + the npm 10.9.7 it
bundles, so the npm check fails and setup.ps1 falls into the
"winget install Node.js LTS" branch (~35 s) for a Node reinstall
we do not actually need. `npm install -g npm@^11` upgrades the
bundled npm in-place in ~5 s, which lets setup.ps1 short-circuit
on the existing Node 22.
(2) windows-latest's Windows Defender real-time scanning opens and
hashes every file the install writes. Vite/Tailwind/TSC produce
thousands of small chunks during the frontend build, and uv pip
extracts thousands of small files per wheel. The scan latency
dominates both. Adding Add-MpPreference -ExclusionPath entries
for the four directories Studio writes to drops per-file open
latency from ~ms to ~us. The runneradmin user has the privilege
needed; wrap each call in try/catch so a permission flake leaves
the install otherwise unaffected.
Excluded paths:
$env:USERPROFILE\.unsloth (Studio venv + llama.cpp)
$env:USERPROFILE\AppData\Local\uv (uv wheel cache + extracts)
$env:GITHUB_WORKSPACE\studio\frontend\node_modules
$env:GITHUB_WORKSPACE\studio\frontend\dist
Six Windows jobs touched (4 workflows, with the inference workflow
fanning out to 3 jobs):
studio-windows-update-smoke.yml (1 job)
studio-windows-api-smoke.yml (1 job)
studio-windows-ui-smoke.yml (1 job)
studio-windows-inference-smoke.yml (3 jobs: openai-anthropic,
tool-calling, json-images)
The new "Pre-install Windows tweaks" step is identical across every
Windows job; the rationale is described once in
studio-windows-update-smoke.yml and cross-referenced from the others.
Expected savings per Windows job:
- npm fix: ~35 s saved (winget Node reinstall skipped)
- Defender exclusions: ~30-90 s saved (frontend / uv-pip-extract)
- Combined: ~60-120 s per job, or ~6-12 min CPU per PR push across
all 6 Windows jobs.
Not addressed (out of scope for this commit):
- The fundamental Vite/TSC/Tailwind frontend build cost on NTFS.
Optimising that would mean changing the build pipeline (e.g.
skipping `tsc -b` and relying on type-check elsewhere), which is
much more invasive.
- The uv pip extraction cost. The actions/setup-python@v5 cache
already caches pip wheels; uv has its own cache that we could
cache separately, but the cache restore overhead on Windows
(76 s for the venv we tried and reverted) tends to eat the
savings -- the Defender exclusion above goes after the same
cost via a different lever.
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