pytorch-ci

Out-of-tree CI for PyTorch on RISC-V.

Overview

This repository is a downstream CI for pytorch/pytorch, registered as a PyTorch Out-of-Tree CI.

The relay mechanism is defined in RFC #90, which describes the Cross-Repo CI Relay (CRCR) architecture: GitHub webhooks from pytorch/pytorch are forwarded via repository_dispatch events to registered downstream repositories at increasing trust levels (L1–L4).

Workflows

out-of-tree-ci.yml — Dispatch receiver

Listens for repository_dispatch (push) events forwarded by the CRCR relay from pytorch/pytorch. Triggers the main ci.yml workflow when any of the following conditions match:

• A commit lands on refs/heads/main (via refs/tags/trunk/ tag)
• The ciflow/docker label is applied (Docker image changes in .ci/docker)
• The ciflow/riscv64 label is applied

ci.yml — Build pipeline

Triggered by the dispatch receiver (or manually via workflow_dispatch) with a ref/sha pair pointing to a commit in pytorch/pytorch.

docker-builds job — Runs on ubuntu-24.04. Builds and pushes a cross-compilation Docker image (pytorch-linux-noble-riscv64-py3.12-gcc14) to GHCR, using QEMU + Docker Buildx. Skips the build if the image for the current .ci/docker tree hash already exists.

linux-noble-riscv64-py3_12-build job — Runs on ubuntu-24.04-riscv self-hosted runners. Checks out pytorch/pytorch at the given ref, merges pytorch/pytorch#182278 (in-flight RISC-V patches), then builds PyTorch inside the Docker container using .ci/pytorch/build.sh. Build artifacts (dist/, build/lib, build/bin) are uploaded as GitHub Actions artifacts with a 14-day retention.

Build caching

The build uses a custom sccache binary with a Redis-backed distributed coordinator, allowing multiple concurrent RISC-V build jobs to share compilation work. The cache bucket is hosted on Scaleway Object Storage (s3.fr-par.scw.cloud).