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lancedb/.github/workflows/build_linux_wheel/action.yml
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Tobias 7b6ee0d655 feat(wheels): publish lancedb-compat for pre-Haswell x86_64 hosts (#3327)
Tracks #3324. On x86_64 CPUs without AVX2 (Sandy Bridge / Ivy Bridge /
Westmere on Intel; Bulldozer / Piledriver / Steamroller on AMD), `import
lancedb` SIGILLs because the wheel bakes AVX2 + FMA into every compiled
function. Per [westonpace's
review](https://github.com/lancedb/lancedb/issues/3324#issuecomment-4328944354),
the default `lancedb` wheel stays fast; pre-Haswell users get a
separately-published `lancedb-compat` wheel.

## Summary

- Adds a `lancedb-compat` matrix entry to `pypi-publish.yml` that builds
with `RUSTFLAGS="-C target-cpu=x86-64-v2"` (Nehalem-class baseline).
Same Python API (`import lancedb` works) — files install to the same
namespace, so the two wheels conflict at install time and users pick
one. Same pattern as `psycopg2` / `psycopg2-binary` and `tensorflow` /
`tensorflow-cpu`.
- Generalizes `build_linux_wheel` and `upload_wheel` composites with
optional `package-name` and `rustflags` inputs (defaults preserve the
existing 4 `lancedb` matrix entries verbatim).
- Documents the choice in `python/README.md`: `pip install
lancedb-compat` for pre-Haswell hosts.

The default `.cargo/config.toml` baseline is unchanged.

## Sequencing

1. ~~lance-format/lance#6630 merges → runtime SIMD dispatch lands in
lance.~~ **Done — merged.**
2. lancedb's lance dep is bumped to a release that includes it (separate
PR / normal cadence).
3. This PR's `lancedb-compat` wheel build path starts producing a wheel
that runs on pre-Haswell hardware. **Maintainer setup**: register
`lancedb-compat` on PyPI and configure trusted publishing.

## Verified end-to-end on Sandy Bridge Xeon E5-2609

Verification was done locally against a fork-pinned lance dep that
includes the runtime dispatch implementation, using the same
`RUSTFLAGS="-C target-cpu=x86-64-v2"` flags this PR uses in CI:

```
$ RUSTFLAGS="-C target-cpu=x86-64-v2" maturin build --release
$ pip install ./target/wheels/lancedb-*.whl
$ python verify.py
PASS: import + simd dispatch + table create + vector search all work.
```

Pre-fix on the same CPU (default `pip install lancedb`): `Illegal
instruction (core dumped)`. Full reproducer (deps + clone + build +
verification):
https://gist.github.com/tobocop2/2e341358b55c143527416edfdb1e37df.
Fork-internal verification PR with the dep bump and full logs:
[`tobocop2/lancedb#2`](https://github.com/tobocop2/lancedb/pull/2).

## Benchmarks — no regressions on modern CPUs from the lance-side change

These are the numbers I ran for the lance PR, confirming the runtime
dispatch doesn't slow down the default (`target-cpu=haswell`) wheel that
existing users install. Criterion, one machine, one session, base → PR,
no `RUSTFLAGS` override. Full methodology, null experiments, and logs:
[lance-format/lance#6630 benchmark
comment](https://github.com/lance-format/lance/pull/6630#issuecomment-4933063394)
and the [logs
gist](https://gist.github.com/tobocop2/3c6d0f449cbd736aa2501f89a7fe56a2).

| benchmark | EPYC 7B13 (`avx2`, `fma`, no `avx512f`) | Xeon Cascade
Lake (`avx512f`) |
|---|---|---|
| `Cosine(f32, scalar)` *(control)* | +0.04% | +0.09% |
| `Cosine(f64, scalar)` | −0.34% | −1.94% |
| `Cosine(u8, SIMD)` | +2.30% | +3.63% |
| `Dot(f16, SIMD)` | −0.58% | +0.61% |
| `Dot(f32, SIMD)` | +0.34% | **−6.08%** |
| `Dot(f32, arrow_arity)` | +0.02% | −0.00% |
| `L2(f32, scalar)` | −0.10% | −0.02% |
| `L2(f32, simd)` (dim 1024) | +2.63% | −0.53% |
| **`L2(simd,f32x8)` (dim 8)** | **−45.9%** | **−25.1%** |
| `L2(u8, SIMD)` | +0.42% | −3.11% |
| `NormL2(f32, SIMD)` | −1.02% | −4.17% |
| `NormL2(f64, SIMD)` | +3.51% | −0.58% |

Nothing regresses beyond the noise floor. Dim 8 — the PQ sub-vector
width — improves 25–46%.

---

To be transparent: this isn't my domain of expertise and the lance-side
implementation is AI-generated. I verified it works end-to-end on the
failing hardware. Happy to roll in feedback.
2026-07-16 10:54:42 -07:00

85 lines
3.5 KiB
YAML

# We create a composite action to be re-used both for testing and for releasing
name: build-linux-wheel
description: "Build a manylinux wheel for lance"
inputs:
python-minor-version:
description: "10, 11, 12, 13"
required: true
args:
description: "--release"
required: false
default: ""
arm-build:
description: "Build for arm64 instead of x86_64"
# Note: this does *not* mean the host is arm64, since we might be cross-compiling.
required: false
default: "false"
manylinux:
description: "The manylinux version to build for"
required: false
default: "2_17"
package-name:
description: "Override [project] name in python/pyproject.toml (e.g. 'lancedb-compat'). Default keeps 'lancedb'."
required: false
default: "lancedb"
rustflags:
description: "RUSTFLAGS for the build container, as a single whitespace-free token (e.g. '-Ctarget-cpu=x86-64-v2'). Empty leaves RUSTFLAGS unset, keeping the defaults from .cargo/config.toml."
required: false
default: ""
runs:
using: "composite"
steps:
- name: CONFIRM ARM BUILD
shell: bash
env:
ARM_BUILD: ${{ inputs.arm-build }}
run: |
echo "ARM BUILD: $ARM_BUILD"
- name: Patch package name for variant build
if: ${{ inputs.package-name != 'lancedb' }}
shell: bash
env:
PACKAGE_NAME: ${{ inputs.package-name }}
run: |
# Swap the [project] name so this build produces e.g. lancedb-compat
# wheels. The package still installs files under the lancedb/
# namespace -- import lancedb still works after pip install.
sed -i.bak 's/^name = "lancedb"$/name = "'"$PACKAGE_NAME"'"/' python/pyproject.toml
rm -f python/pyproject.toml.bak
grep '^name = ' python/pyproject.toml
- name: Build x86_64 Manylinux wheel
if: ${{ inputs.arm-build == 'false' }}
uses: PyO3/maturin-action@v1
with:
maturin-version: "1.12.4"
command: build
working-directory: python
docker-options: "-e PIP_EXTRA_INDEX_URL='https://pypi.fury.io/lance-format/ https://pypi.fury.io/lancedb/' -e PROTOC=/usr/local/bin/protoc ${{ inputs.rustflags != '' && format('-e RUSTFLAGS={0}', inputs.rustflags) || '' }}"
target: x86_64-unknown-linux-gnu
manylinux: ${{ inputs.manylinux }}
args: ${{ inputs.args }}
before-script-linux: |
set -e
curl -fsSL https://github.com/protocolbuffers/protobuf/releases/download/v24.4/protoc-24.4-linux-x86_64.zip -o /tmp/protoc.zip
unzip /tmp/protoc.zip -d /usr/local
rm /tmp/protoc.zip
/usr/local/bin/protoc --version
- name: Build Arm Manylinux Wheel
if: ${{ inputs.arm-build == 'true' }}
uses: PyO3/maturin-action@v1
with:
maturin-version: "1.12.4"
command: build
working-directory: python
docker-options: "-e PIP_EXTRA_INDEX_URL='https://pypi.fury.io/lance-format/ https://pypi.fury.io/lancedb/' -e PROTOC=/usr/local/bin/protoc ${{ inputs.rustflags != '' && format('-e RUSTFLAGS={0}', inputs.rustflags) || '' }}"
target: aarch64-unknown-linux-gnu
manylinux: ${{ inputs.manylinux }}
args: ${{ inputs.args }}
before-script-linux: |
set -e
yum install -y clang
curl -fsSL https://github.com/protocolbuffers/protobuf/releases/download/v24.4/protoc-24.4-linux-aarch_64.zip -o /tmp/protoc.zip
unzip /tmp/protoc.zip -d /usr/local
rm /tmp/protoc.zip
/usr/local/bin/protoc --version