orca/docs/reference/ci-runner-efficiency.md

# CI efficiency and runner capacity

## September 25 follow-up

The current queue is a bigger part of PR latency than setup. Successful full PR
[36212793136](https://github.com/stablyai/orca/actions/runs/36212793136) used
**74.6 aggregate runner-minutes**, including **55.5** for its eight unit shards.
Those jobs ran for 315–448 seconds but waited 229–1,076 seconds to start. The
three-second final `verify` job waited another 264 seconds. These are observed
job creation-to-start and start-to-completion intervals, not billing figures.

This follow-up keeps the existing tests, isolation, eight unit shards, platform
coverage, and release behavior:

- Make the reusable unit-test call and final aggregate respect cancellation.
  Their old `always()` conditions kept superseded work alive despite workflow
  cancellation. In [36215475069](https://github.com/stablyai/orca/actions/runs/36215475069),
  a newer push cancelled ordinary jobs while all eight unit shards remained
  queued and the replacement workflow remained pending. `!cancelled()` still
  evaluates after failed/skipped dependencies, without resisting cancellation.
  Two other superseded PR runs reproduced this: at 04:27 UTC on September 26,
  [36216165253](https://github.com/stablyai/orca/actions/runs/36216165253) and
  [36215543186](https://github.com/stablyai/orca/actions/runs/36215543186) still held
  11 runners, with two more obsolete jobs queued. They had consumed another
  71.3 runner-minutes after replacement pushes. After rechecking current PR heads
  and replacement runs, both obsolete runs were force-cancelled; their replacements
  left the blocked pending state.
- Combine root/README guards with change detection. A real sparse checkout kept
  all 29,487 index entries while materializing only 12 files (192 KB). This
  eliminates one runner allocation and checkout per PR. README link checks still
  see tracked targets outside the working tree and run on docs-only PRs.
- Use free `ubuntu-slim` containers for small guard/aggregate/API jobs; trial
  free `ubuntu-24.04-arm` for typechecking, which needs no native runtime.
  Both share the account's standard concurrency limit. Different labels do
  **not** grant extra concurrent jobs; hosted timings determine their value.
- Cancel superseded PR attempts in the Git termination, Pi owner, and Pi provider
  runtime workflows, retaining independent manual runs.
- Fetch only complete HEAD ancestry for cloud secret scanning. The old checkout
  fetched every branch and tag and took 55 seconds in
  [36214130174](https://github.com/stablyai/orca/actions/runs/36214130174).
  Real Git fixtures prove both merge parents and deleted historical contents
  still produce the identical scanned patches.
- Remove the cloud lockfile from the eight unit shards' download-cache key; the
  dedicated relay integration job still includes it. Record actual per-file
  environment, setup, import, and test durations for the existing shard planner.
  Shard 4 spent 535 worker-seconds importing and 357 executing tests; a uniform
  per-file import estimate misses that cost. See [timing refresh](../../config/scripts/ci-shard-timings.md).
- Seed Node 24 native modules, the pinned Git compatibility binary, and TypeScript
  state on the default branch, hourly
  and when dependency/toolchain inputs change. One ten-minute-bounded hosted job
  reuses existing cache keys and skips typechecking an already-cached commit.
  New PRs can restore default-branch caches, while caches saved by another PR
  are inaccessible. The audit found 80 entries totaling 10.67 GiB, including
  9.31 GiB of pnpm stores, but no main-branch Node 24 native or TypeScript state.
  Seven PRs held separate copies of the same pnpm key (2.36 GB combined).
  Git preparation now has one shared action with the unchanged cache key,
  checksum, and build command. In
  [36212101873](https://github.com/stablyai/orca/actions/runs/36212101873), a new PR
  spent 40 seconds compiling the same Git 2.25.5 binary; main-branch warming
  makes that cache available to new PRs too.

The hosted trial also removes repeated work in mobile bundle checks. The
builder keeps private snapshots of the default real output for read-only checks
(15 identical builds become two), and haptics checks reuse each route closure
(32 builds become eight). Determinism, custom inputs, malformed routes, stale
outputs, and tampered manifests retain independent builds. A mutation regression
proves Buffer/manifest consumers cannot change another assertion's fixture.
The grant census reuses parsed references for unchanged file contents, still
reads source every time, and has a real-file edit invalidation regression.
The first hosted mobile lane used 400 seconds for its 448 tests; the grant
census alone took 259 seconds. Locally, the same one-worker invocation of the
three changed files fell from 243.07 seconds (101 passing tests) to 49.49 seconds
(103 passing tests). Hosted run
[36217238462](https://github.com/stablyai/orca/actions/runs/36217238462) retained
the same 43 files and passed all 450 tests: the original 448 plus two regressions.
Its test step fell from 400.26 to 205.17 seconds, and the complete job fell from
498 to 298 seconds (40% less runner time). Builder, haptics, and grant-census file
times fell from 73.70/88.94/258.58 seconds to 29.24/32.98/22.58 seconds.
The later default-worker verification retained the same 450-test coverage, but
its unchanged terminal-render test failed twice on the pre-existing timing
assertion that a frame must be pending at disposal (`expected 0 to be greater
than 0`). Its other 449 tests passed; no mobile source or assertion was relaxed.

A four-worker experiment reduced aggregate unit job time from 3,386 to 3,133
seconds (7.5%), but the repeat run exceeded the palette matcher's existing
180ms performance budget at 235ms. The override was removed; retain Vitest's
default worker count, isolation, timeouts, retries, and coverage. The first trial
also found an outdated hook-order snapshot after main added three layout-persistence
hooks. That snapshot was refreshed only after comparing the exact old and merged
hook sequences. Final verification is linked from
[PR #23053](https://github.com/stablyai/orca/pull/23053). Failed timing reports
never replace the checked-in baseline.

No account settings, paid services, or runner entitlements changed. Standard
public-repository runners remain free. GitHub documents plan concurrency limits
of Free 20, Pro 40, Team 60, Enterprise 500, and permits support requests for
increases. The organization's actual entitlement was not exposed by the API.
See [runner specifications](https://docs.github.com/en/actions/reference/runners/github-hosted-runners)
and [concurrency limits](https://docs.github.com/en/actions/reference/limits).

Hosted observations from [PR run 36215718607](https://github.com/stablyai/orca/actions/runs/36215718607):

| Check                                     | Earlier sample |        Trial | Result               |
| ----------------------------------------- | -------------: | -----------: | -------------------- |
| Detection plus repository guards          |  54s, two jobs | 26s, one job | Passed               |
| Typecheck (whole job)                     |       109s x64 |      81s ARM | Passed               |
| Typecheck command, cold incremental state |        76s x64 |      51s ARM | Passed               |
| Cloud secret scan (whole job)             |            69s |          55s | Passed               |
| Cloud checkout/history fetch              |            55s |          40s | Identical scan scope |

The [warmup trial](https://github.com/stablyai/orca/actions/runs/36215718295)
passed in 54 seconds. Its x64 compiler restored the ARM job's incremental state
and rechecked the same source in eight seconds. Unit shard 3 subsequently
restored its pnpm/native cache keys successfully. Actual sharing across different
PRs requires the producer to land on the default branch; this trial validates
commands and key compatibility, not a completed default-branch rollout.
The follow-up warmup built the Git binary in 40 seconds; the PR Git check restored
that exact key and passed in 62 seconds overall. Its TypeScript refresh took
seven seconds after restoring earlier incremental state.

These are small observational samples from different revisions, not controlled
benchmarks. The cold typecheck log confirms an incremental-cache miss. Queue
changes must be separated from active duration and concurrent account traffic.
The checked-in shard weights remain unchanged; the new reports make future
refreshes possible from complete successful runs.

## September 5 audit

Audit date: September 5, 2026. No paid capacity or provider configuration changed.

## Measurements and changes

Three recent successful PR runs used 54.6–64.9 aggregate runner minutes:
[33998366568](https://github.com/stablyai/orca/actions/runs/33998366568),
[33998220287](https://github.com/stablyai/orca/actions/runs/33998220287), and
[33998181502](https://github.com/stablyai/orca/actions/runs/33998181502).
These are sums of active job durations, excluding skipped jobs; they are not
billing minutes or queue time. This small sample is not a historical average.

- Consolidate E2E routing into the existing code-path detector. The removed
  detector occupied 20–22 seconds and required another runner allocation and
  full-history checkout per nondraft code PR. The same routing commands remain,
  including SSH and native IME selection; actual E2E results remain advisory.
  A routing-script error now fails the required code-path detector.
- Use gzip for PR-only Debian/RPM artifacts. The two sampled Linux packaging
  jobs took 8m10s and 8m19s overall; one spent 3m47s in electron-builder. Its
  default Debian/RPM compression is xz. PR artifacts are inspected on the same
  runner, so their download size offers no benefit. Keep all AppImage, Debian,
  RPM, payload, launcher, and shutdown checks. Release compression is unchanged.
  Hosted validation in [33999422341](https://github.com/stablyai/orca/actions/runs/33999422341)
  reduced the package-build step to 2m13s and the full Linux job to 6m17s, with
  all existing checks passing. This is a small observational sample.
- Cancel superseded Mobile Checks and Skill update round-trip PR runs. The
  skill matrix has 13 jobs. Preserve non-cancelling main/merge-group skill runs,
  with separate concurrency groups per event.
- Reuse the existing script-free root dependency action in Mobile Checks,
  including the pnpm cache keyed by both root and mobile lockfiles. The root
  install remains necessary because mobile types import root dependencies.

The repository already has eight unit shards, path-scoped platform checks,
native caches, one shared E2E build, PR cancellation, incremental TypeScript
caching, and changed-spec E2E routing. Increasing shards would increase setup
work and simultaneous runner demand. Do not adjust the count without comparing
critical-path time and aggregate job time on the same commit.

## Follow-up savings

- Move the hourly main/release freshness lookup to a five-minute Ubuntu
  preflight without a checkout. In unchanged run
  [33986205749](https://github.com/stablyai/orca/actions/runs/33986205749),
  Blacksmith macOS was occupied for 40 seconds, including a 30-second checkout,
  before skipping. The new job-level gate avoids that Mac allocation. Actual
  builds gain an Ubuntu scheduling hop; pin the Mac checkout and downstream
  Windows identity to the SHA that the preflight checked.
- Avoid global `npm install -g node-gyp` for validated Linux Node-runtime cache
  hits. Use the existing native-module load/provenance check before skipping;
  misses, broken addons, and Electron jobs still install the rebuild toolchain.
  The action file participates in cache keys, so this rollout creates fresh
  native caches once. No measured warm-cache seconds are claimed yet.

## Runner recommendations

The repository is **public**, verified using the GitHub API. Standard
GitHub-hosted Linux, Windows, and macOS runners have free compute minutes for
public repositories. Queue pressure and third-party provider allowances still
matter; artifact storage and larger runners have separate billing rules.
See [GitHub Actions billing](https://docs.github.com/en/billing/concepts/product-billing/github-actions).

1. Keep standard GitHub-hosted runners as the default. Ask GitHub Support for a
   higher concurrent-job limit before paying for more capacity. The documented
   standard limits depend on the account plan (Free: 20 total/5 macOS; Team:
   60/5; Enterprise: 500/50), and increases are subject to approval. The actual
   account entitlement was not verified. See [limits](https://docs.github.com/en/actions/reference/limits).
2. Reserve existing Blacksmith allowance for macOS if that is the priority.
   Blacksmith documents 3,000 free x64 2-vCPU-equivalent minutes per organization;
   a 6-vCPU Mac minute consumes 20 equivalents, or 150 actual Mac minutes if
   it uses the entire free pool. Cloud workflows also use Blacksmith Linux.
   Moving Linux to hosted GitHub saves shared allowance, but does not necessarily
   free Mac hardware capacity. Account-specific contracts and usage were not
   inspected. See [Blacksmith runners](https://docs.blacksmith.sh/blacksmith-runners/overview).
3. Treat Ubicloud as an optional small Linux overflow trial. Its documented
   $2.50 monthly credit buys 1,250 premium 2-vCPU minutes at $0.002/minute, or
   2,000 standard 2-vCPU minutes at $0.00125/minute. New accounts default to
   premium and require a credit card. No enforceable hard spending cap was
   verified, so changing runner labels cannot guarantee the no-spend constraint.
   One PR's roughly 55–65 runner minutes also makes clear how small this pool
   is relative to repository activity (hardware speeds differ).
   See [pricing](https://ubicloud.com/docs/about/pricing) and
   [setup](https://ubicloud.com/docs/github-actions-integration/quickstart).

### A bounded Ubicloud candidate

The Linux leg of `performance-contracts.yml` took 48 seconds in
[33994756657](https://github.com/stablyai/orca/actions/runs/33994756657).
Its daily schedule and 20-minute timeout make it a small candidate: 31 ordinary
scheduled attempts permit at most 620 job-runtime minutes, before runner
startup/cleanup billing. Actual timings on Ubicloud's 2-vCPU hardware still need
measurement; the GitHub timing is only a sizing reference.

If enabled later, route only the first attempt of the scheduled Linux job to
Ubicloud; keep PRs, manual dispatches, reruns, and macOS/Windows on GitHub. This
avoids spending the allowance on unpredictable PR volume. Check other account
usage and available credit before enabling; a workflow timeout is not an
account-wide billing cap. On September 5, the organization's GitHub App
installation list contained Blacksmith but no Ubicloud installation, so this
follow-up leaves runner selection on GitHub rather than queueing work against
an unprovisioned label.

## Machines that also run coding agents

Do not register the credentialed host directly as a public-PR runner. A PR can
execute arbitrary build/test code, and a persistent host lets it access local
credentials or affect subsequent jobs. Docker alone is not adequate isolation
when it exposes the host home, Docker socket, SSH agent, or office network.

A possible no-new-hardware experiment is a disposable VM per job, preferably on
a dedicated spare machine, with a just-in-time single-job runner, no shared
home/keychain/SSH agent or host mounts, restricted network access, and CPU/RAM
limits that leave room for coding agents. Destroy the VM after every job;
ephemeral runner registration by itself does not clean the machine. Start with
trusted branch/manual workloads and keep public fork PRs on hosted runners.
Provisioning and ongoing patching are real operational costs even when the
machine is already owned. See GitHub's
[self-hosted runner security guidance](https://docs.github.com/en/actions/security-for-github-actions/security-guides/security-hardening-for-github-actions).

## Release waits

The latest successful sampled Windows release used 13m59s of a 21m56s job in
signing wait/download steps. The same release held an Ubuntu job for 11m38s
polling the isolated Mac build. These are stronger occupancy opportunities than
small checkout savings, especially when approval takes hours.

[Windows signing without occupying a runner](windows-signing-runner-time.md)
describes a staged, same-run design, required protected environments, and
rehearsal criteria. No callback integration or protected Windows signing
environments currently exist. An environment-gated design adds a GitHub
approval after each SignPath approval and changes the current automatic inner
signing timeout fallback; those are explicit release-policy decisions, so this
PR leaves production signing behavior unchanged.

## Second audit and hosted trials

- Cloud Verify ran 100 times in a sampled 39-hour window (84 PR and 16 push
  runs). Move its four Ubuntu 22.04 jobs from Blacksmith to standard hosted
  Ubuntu 22.04, preserving Postgres, secret scanning, build, tests, and Terraform
  validation. Baseline [34001538145](https://github.com/stablyai/orca/actions/runs/34001538145)
  used 64/72/26/19 seconds for security/test/build/Terraform respectively.
  This conserves the shared provider allowance; hosted latency must be checked.
- Keep full tag history for the 13-job skill round-trip matrix, but fetch blobs
  lazily. Only two historical SKILL.md files are materialized. Baseline
  [33999994876](https://github.com/stablyai/orca/actions/runs/33999994876)
  spent 42–84 seconds per checkout, about 14 aggregate runner minutes. A hosted
  trial must verify historical blob fetches on all three operating systems.
- Use the existing Electron/native dependency cache for native IME CI. Keep
  both deterministic boundary and real IBus tests. Add pnpm store caching to
  terminal perf and release golden/evidence lanes; retain their raw installs
  because manually selected older refs may not contain the shared action.
- Disable ZIP recompression only for already-compressed NSIS installers sent
  to SignPath. Installer contents, release compression, and signing stay intact.
- Advance existing placement and startup deadlines with scoped fake timers in
  three renderer test files. All 34 tests pass in 62 ms of local test execution,
  versus 65.182 seconds in the sampled hosted baseline. Imports and transforms
  still dominate invocation time; this is not a claim of equal PR wall savings.

Eight unit shards already have balanced 260–296-second sample durations.
Reducing shards or removing test isolation lacks evidence of a net gain. Real
subprocess tests intentionally cover lifecycle behavior and retain real clocks.
The 14-way E2E split retains headroom after earlier 12-way timeouts. Lowering
coverage or schedule frequency is outside this efficiency pass. Cache complexity
for a seven-second docs install is unlikely to pay back. Release build reuse
across modes risks differing telemetry identities and native platform artifacts.

Terminal Perf's baseline [33955846492](https://github.com/stablyai/orca/actions/runs/33955846492)
failed waiting 30 seconds for workspaceSessionReady in its shared-page fixture,
before measuring terminal performance. Compare hosted trials against that known
failure rather than attributing it to dependency cache changes.

Hosted trials for the second audit:

- [Cloud Verify 34002295216](https://github.com/stablyai/orca/actions/runs/34002295216)
  passed all four jobs on standard hosted Ubuntu: security 57s, test 102s, build
  35s, Terraform 19s. The test lane is 30s slower than the Blacksmith sample;
  retain this modest latency tradeoff to conserve shared allowance.
- [Skill matrix 34002295221](https://github.com/stablyai/orca/actions/runs/34002295221)
  passed all 13 legs, including historical blob materialization. Checkout took
  18–20s on Linux, 39–45s on macOS, and 49–58s on Windows, versus the earlier
  42–84s range across platforms. These are observational samples.
- [Native IME 34002299594](https://github.com/stablyai/orca/actions/runs/34002299594)
  passed both deterministic and real IBus checks. Shared dependency setup took
  29s, versus 35s for the old install/toolchain steps in the sampled baseline.
- Native-IME-only source/spec changes no longer allocate the reusable E2E
  build, cache, and consumer jobs just to filter out the native spec. The
  separate native workflow still runs; SSH-only and mixed spec lists still
  allocate the reusable workflow. Routing contracts exercise these cases.
- [Hourly 34001816449](https://github.com/stablyai/orca/actions/runs/34001816449)
  exercised the new five-second preflight and successfully published macOS.
  The Windows follow-up failed in its unchanged input-vetting fetch because
  remote refs differ only by case on its case-insensitive filesystem. The
  requested SHA was correct; this does not validate an unchanged-main skip yet.

Moving the daily Mac freshness check has lower expected value than hourly:
only one potential idle allocation per day, and active development usually
requires that build. Defer another release-graph change until skip frequency
justifies it. The substantive remaining release occupancy opportunity is the
separately documented asynchronous signing policy decision.