open-standards/.github/workflows/wai-quantum-lang.yml
Transaction Science 6517401f01 CI: the gate that decides whether a workflow runs was queued behind the work it gates
Every path-gated workflow begins with one small job -- `does this change touch
it`, or `which workspaces this change touches` for the standards build -- that
all of its real jobs declare in `needs`. All 55 of those gate jobs ran on
`linux-arm64`.

That is the one label the fleet cannot spare. Sampled while 267 runs were
queued, every waiting run had the same shape:

    [waiting]  linux-arm64    does this change touch it
    [blocked]  linux          member · dataflow device, simulated
    [blocked]  macos          member · dataflow device absent

237 runs, each holding a gate in the longest queue, and every real job blocked
behind it. Not only `linux` jobs: `macos`, `linux-hw`, `linux-arm64-hw` and
`macos-m3-ultra` jobs were blocked too. The measured effect was `linux-arm64`
263 deep against `linux` **zero**, with jetson-hub's 20 cores taking no job for
a full hour -- starved not for want of work but because the work could not be
unblocked. A gate waiting on the resource it is rationing is head-of-line
blocking, and it makes every other runner in the fleet idle on its behalf.

The gates move to `linux`. Nothing else changes: the diff is 55 `runs-on` lines
and no others, and every touched file still parses.

Why `linux` and not elsewhere. The gate is not free -- it compares
`BASE...HEAD`, which needs the merge base, so `fetch-depth: 0` is a full clone
rather than a ten-second script. `macos` is served by hosts on a Mac Studio
sitting at load 185; `linux` is a separate 20-core box that was measurably
empty. This moves a serialisation point to the least contended label; it does
not remove it, and the gate is still a single point of failure for its
workflow. The structural fix is an early-exit first step inside each job, which
costs one checkout per leg and is a larger change.

Follow-up, deliberately not bundled: jetson-hub runs at capacity 2 with 15 GB of
RAM, so 55 clones still serialise two at a time. Raising capacity helps gates
and hurts the heavy emulated-architecture jobs that share the label, so it wants
measuring on its own.

Co-Authored-By: Claude Opus 5 <[email protected]>
2026-11-03 15:19:13 -05:00

147 lines
6.5 KiB
YAML

name: wai-quantum OpenQASM reader
# The OpenQASM reader every surface uses (wai/wai-quantum/src/qasm.rs and
# src/qasm/): its unit tests (the lexer, the parser, the elaborator, the
# diagnostic table and the page that documents it, every modifier against the
# matrix it must equal, every condition compiled to steps against every value
# of its bits), and the OpenQASM 3 conformance corpus
# (wai/quantum-conformance/qasm3/: the specification's example programs and a
# program for each construct, each with what the reader must do with it).
#
# The corpus runs natively, where a second test holds its bundle equal to its
# files, and under wasm32-wasip2 by wasmtime, where the cases come from the
# bundle the test compiles in. The browser build runs the corpus too
# (wai-web-wasm.yml, wai-web's wasm32 tests). The reader is also built without
# the lowerings (features quantum_lang and quantum_toolchain), as the edge
# component builds it.
concurrency:
group: ${{ github.workflow }}-${{ github.ref }}
cancel-in-progress: true
on:
push:
branches: [main]
paths:
- 'wai/wai-quantum/**'
- 'wai/quantum-conformance/qasm3/**'
- 'rust-toolchain.toml'
- '.github/workflows/wai-quantum-lang.yml'
pull_request:
paths:
- 'wai/wai-quantum/**'
- 'wai/quantum-conformance/qasm3/**'
- 'rust-toolchain.toml'
- '.github/workflows/wai-quantum-lang.yml'
jobs:
relevant:
name: does this change touch it
runs-on: linux
outputs:
run: ${{ steps.gate.outputs.run }}
steps:
- uses: actions/checkout@v5
with:
fetch-depth: 0
- id: gate
run: |
set -euo pipefail
r=$(python3 scripts/pr-touches-paths.py .github/workflows/wai-quantum-lang.yml \
"${{ github.event.pull_request.base.sha }}" \
"${{ github.event.pull_request.head.sha }}")
echo "this change touches the OpenQASM reader: $r"
echo "run=$r" >> "$GITHUB_OUTPUT"
native:
name: reader and corpus · linux
needs: relevant
if: needs.relevant.outputs.run == 'true'
runs-on: linux
timeout-minutes: 60
steps:
- uses: actions/checkout@v5
- name: Install Rust 1.98.0
shell: bash
run: |
export PATH="$HOME/.cargo/bin:$PATH"
command -v rustup >/dev/null 2>&1 || \
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile minimal --default-toolchain 1.98.0
rustup toolchain install 1.98.0 --profile minimal
rustup default 1.98.0
echo "$HOME/.cargo/bin" >> "$GITHUB_PATH"
# A module filter is satisfied by any one test of the module, so each
# module's tests are required by name to have run.
- name: The reader's unit tests
shell: bash
working-directory: wai/wai-quantum
run: |
set -euo pipefail
cargo test --locked --release --features full --lib qasm 2>&1 | tee "$RUNNER_TEMP/qasm.log"
grep -qE '^test result: ok\. [1-9][0-9]+ passed; 0 failed' "$RUNNER_TEMP/qasm.log" || { echo "::error::the reader's tests did not pass"; exit 1; }
for m in qasm::diag qasm::lex qasm::parse qasm::value qasm::lang_tests qasm::tests quantum_toolchain::tests::qasm_round_trip; do
grep -q "^test $m.* \.\.\. ok$" "$RUNNER_TEMP/qasm.log" || { echo "::error::no test of $m ran"; exit 1; }
done
- name: The conformance corpus
shell: bash
working-directory: wai/wai-quantum
run: |
set -euo pipefail
cargo test --locked --release --features full --test qasm3_conformance 2>&1 | tee "$RUNNER_TEMP/corpus.log"
grep -q 'test result: ok. 2 passed; 0 failed' "$RUNNER_TEMP/corpus.log" || { echo "::error::the corpus did not pass"; exit 1; }
- name: The reader without the lowerings
shell: bash
working-directory: wai/wai-quantum
run: |
set -euo pipefail
cargo check --locked --no-default-features --features quantum_lang --lib
cargo check --locked --no-default-features --features quantum_toolchain --lib
wasip2:
name: corpus under wasm32-wasip2 (wasmtime)
needs: relevant
if: needs.relevant.outputs.run == 'true'
runs-on: linux
timeout-minutes: 60
steps:
- uses: actions/checkout@v5
- name: Install Rust 1.98.0 with the wasm32-wasip2 target
shell: bash
run: |
export PATH="$HOME/.cargo/bin:$PATH"
command -v rustup >/dev/null 2>&1 || \
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile minimal --default-toolchain 1.98.0
rustup toolchain install 1.98.0 --profile minimal
rustup default 1.98.0
rustup target add --toolchain 1.98.0 wasm32-wasip2
echo "$HOME/.cargo/bin" >> "$GITHUB_PATH"
# The release binary, pinned by version and SHA-256, rather than a build from source.
- name: Install wasmtime 49.0.2
shell: bash
run: |
set -euo pipefail
[ "$(uname -m)" = x86_64 ] || { echo "::error::the pinned wasmtime archive is x86_64; this host is $(uname -m)"; exit 1; }
if ! command -v xz >/dev/null 2>&1; then
SUDO=""; [ "$(id -u)" -ne 0 ] && SUDO="sudo"
$SUDO apt-get update -qq
$SUDO apt-get install -y -qq xz-utils
fi
v=49.0.2
f="wasmtime-v$v-x86_64-linux.tar.xz"
curl --proto '=https' --tlsv1.2 -sSfL -o "$RUNNER_TEMP/$f" \
"https://github.com/bytecodealliance/wasmtime/releases/download/v$v/$f"
echo "a4d6e9e3a5a60f527cf7793d674c48930c80c2e8977995b8a275cad3254b9322 $RUNNER_TEMP/$f" | sha256sum -c -
tar -xJf "$RUNNER_TEMP/$f" -C "$RUNNER_TEMP"
echo "$RUNNER_TEMP/wasmtime-v$v-x86_64-linux" >> "$GITHUB_PATH"
# A debug build, so integer overflow panics instead of wrapping. The test
# that reads the corpus's files has no wasip2 build; the one that runs the
# cases from the compiled-in bundle does.
- name: The conformance corpus under wasmtime
shell: bash
working-directory: wai/wai-quantum
env:
CARGO_TARGET_WASM32_WASIP2_RUNNER: wasmtime
run: |
set -euo pipefail
cargo test --locked --target wasm32-wasip2 --features full --test qasm3_conformance 2>&1 | tee "$RUNNER_TEMP/wasip2.log"
grep -q 'test result: ok. 1 passed; 0 failed' "$RUNNER_TEMP/wasip2.log" || { echo "::error::the corpus did not pass under wasip2"; exit 1; }