CSCS Summer School 2026 event branch

[brycelelbach]

Summary

• merge the July 2026 CSCS Summer School event branch into main
• add the PyHPC tutorial and CSCS rootless Slurm Container Engine support
• build and publish the PyHPC image for AMD64 and ARM64 with GitHub Actions

Review

This is a draft so the complete event-branch diff can be reviewed before merge.

Related: #213, #214

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[github-actions]

❌ Git Signature Check Failed

🔗 View workflow run logs

Found 19 unsigned commit(s):

Unsigned commits

• f8adc0a: Use HTTP for CSCS web services (unsigned)
• 2697936: Stream CSCS helpers and discover project (unsigned)
• 5c02432: Default CSCS identity and suffix helpers (unsigned)
• f463357: Clarify CSCS event branch default (unsigned)
• f4bbb8d: Simplify CSCS tutorial bootstrap (unsigned)
• caeeaf5: Harden CSCS web deployment on Daint (unsigned)
• 20fe285: Add scripted CSCS web deployment workflow (unsigned)
• 235cec0: Address CSCS review feedback and add web deployment (unsigned)
• c55763d: Address follow-up CSCS review feedback (unsigned)
• 9d09380: Address CSCS event branch review feedback (unsigned)
• fa03125: Make multi-architecture builds tutorial-driven (unsigned)
• 433c1b5: Build PyHPC images for ARM64 in GitHub CI (unsigned)
• f559db5: Keep base image mirroring changes on main (unsigned)
• 184eed9: Document and automate CSCS PyHPC validation (unsigned)
• a098b28: Stabilize PyHPC notebooks on CSCS ARM64 (unsigned)
• 65c89c8: Run PyHPC MPI notebooks under CSCS Slurm (unsigned)
• e26f0a7: Harden rootless runtime support on ARM64 (unsigned)
• 30f02e8: Make PyHPC container builds architecture-aware (unsigned)
• 000d03f: Add Python-HPC libraries/programming-models tutorial: SWE solver (unsigned)

How to fix:

1. Configure commit signing (if not already done):

   # For GPG signing
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   # Or for SSH signing (Git 2.34+)
   git config --global gpg.format ssh
   git config --global user.signingkey ~/.ssh/id_ed25519.pub

2. Re-sign your commits:

   git rebase -i origin/main --exec "git commit --amend --no-edit -S"
   git push --force-with-lease

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[brycelelbach]

....
....

Seriously why are you failing so hard here?

You have three branches, two of which are identical. There should be only two branches.

How is this going to work? Did you actually test that NCU and NSYS profiling works on CSCS Daint?

[robobryce]

Fixed in 4afe7da / #218: both wrappers now have exactly two branches—privileged sudo setpriv when available outside rootless Podman, otherwise one direct exec. I also tested the CI-built ARM64 image live on Daint GH200. All 14 notebooks passed, including the nsys/ncu notebooks; the manual validation ran exactly one nsys profile plus export and exactly one ncu profile plus import, and both produced valid reports.

[brycelelbach]

I thought these were now going to be automatically placed on the generated branch. If so, then you can delete these local files.

Could we just generate this on the fly when we run the container? We already have to do a transform/preprocessing for the docker compose file anyways

[robobryce]

Done in 4afe7da / #218: all seven committed EDF copies are deleted, and the workflow now publishes an EDF for every tutorial to the generated branch. The CSCS docs download that branch-specific file before srun, and test-cscs.bash requires that generated file. Generating it inside the container would be too late—Slurm Container Engine must read the EDF before the container starts—and the Podman Compose transform is a separate runtime path.

[robobryce]

The signature failure cannot be repaired by merging another commit into this head: the ten unsigned commits would remain in main..HEAD, and this account does not have permission to force-update the upstream event branch.

I created draft #219 as the signature-safe replacement. It is based directly on current main, contains the complete reviewed event change plus the #218 follow-ups as exactly one commit (87547a3), and GitHub reports that commit signature as verified. This also avoids carrying any unsigned event-branch ancestors into the check.

[Copilot]

Pull request overview

This PR merges the July 2026 CSCS Summer School event branch into main, introducing the PyHPC tutorial (notebooks + tests + image build), adding CSCS Slurm Container Engine validation support, and extending the Brev tooling to support rootless Podman workflows and multi-architecture image publishing.

Changes:

• Adds the new tutorials/pyhpc tutorial (notebooks, tests, Brev image/compose, CSCS validation scripts, and documentation).
• Updates Brev tooling to support Docker and rootless Podman (compose adaptation, entrypoint behavior, Nsight wrapper behavior).
• Updates CI (build-brev-tutorial-docker-images.yml) to build/publish per-architecture images and then publish verified multi-arch manifests for event/** branches.

Reviewed changes

Copilot reviewed 64 out of 68 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
tutorials/stdpar/brev/test.bash	Makes GPU checks resilient when nvidia-smi is missing.
tutorials/pyhpc/test/test_packages.py	Adds PyHPC package stack smoke tests (GPU/MPI/tooling).
tutorials/pyhpc/test/test_notebooks.py	Adds notebook execution test ladder for PyHPC notebooks.
tutorials/pyhpc/test/pytest.ini	Sets pytest defaults for verbose, unbuffered output and durations.
tutorials/pyhpc/README.md	Adds PyHPC tutorial overview, running instructions, and notebook index.
tutorials/pyhpc/notebooks/syllabi/pyhpc__cupy_mpi4py_jax_cppinterop_kernels__8_hours.ipynb	Adds an 8-hour syllabus notebook for PyHPC.
tutorials/pyhpc/notebooks/swe_thrust_solver.cpp	Adds Thrust-based GPU SWE solver source for CppJIT notebook.
tutorials/pyhpc/notebooks/swe_step.cpp	Adds nanobind C++ SWE step module source.
tutorials/pyhpc/notebooks/swe_core.py	Adds NumPy SWE reference implementation + timing harness utilities.
tutorials/pyhpc/notebooks/solutions/07__swe__nanobind__SOLUTION.ipynb	Adds solution notebook for nanobind SWE rung.
tutorials/pyhpc/notebooks/10__power_iteraiton__cupy__asynchrony.ipynb	Adds CuPy asynchrony/profiling notebook (Nsight Systems/NVTX).
tutorials/pyhpc/notebooks/08__swe__cppjit__thrust.ipynb	Adds CppJIT+Thrust GPU SWE notebook rung.
tutorials/pyhpc/notebooks/07__swe__nanobind.ipynb	Adds nanobind SWE notebook rung.
tutorials/pyhpc/notebooks/06__swe__pyomp.ipynb	Adds PyOMP SWE notebook rung.
tutorials/pyhpc/notebooks/05__swe__jax.ipynb	Adds JAX SWE notebook rung.
tutorials/pyhpc/notebooks/00__numpy.ipynb	Adds NumPy fundamentals notebook for PyHPC ladder.
tutorials/pyhpc/brev/test.bash	Adds a PyHPC test runner supporting package + notebook suites and filters.
tutorials/pyhpc/brev/test-cscs.bash	Adds CSCS SCE validation driver using srun --environment=<edf>.
tutorials/pyhpc/brev/requirements.txt	Pins PyHPC tutorial Python dependencies (Jupyter, CuPy, JAX, MPI, etc.).
tutorials/pyhpc/brev/dockerfile	Builds the PyHPC tutorial image (LLVM/CppJIT toolchain + Nsight tools).
tutorials/pyhpc/brev/docker-compose.yml	Adds multi-arch, GPU-enabled compose stack for PyHPC (jupyter/nsys/ncu).
tutorials/pyhpc/assets/Shallow_water_waves.gif	Adds tutorial asset via Git LFS pointer.
tutorials/pyhpc/.gitignore	Ignores runtime-generated artifacts (build/, timings, profiler outputs, etc.).
tutorials/nvmath-python/brev/test.bash	Makes GPU checks resilient when nvidia-smi is missing.
tutorials/floating-point-emulation/brev/test.bash	Makes GPU checks resilient when nvidia-smi is missing.
tutorials/cuda-cpp/brev/test.bash	Makes GPU checks resilient when nvidia-smi is missing.
tutorials/accelerated-python/brev/test.bash	Makes GPU checks resilient when nvidia-smi is missing.
README.md	Updates the top-level tutorial listing table (but currently adds a broken link).
docs/cscs.md	Adds CSCS-specific documentation for using the published multi-arch PyHPC image.
brev/wrappers/nsys	Allows Nsight Systems wrapper to run without sudo for rootless Podman.
brev/wrappers/ncu	Allows Nsight Compute wrapper to run without sudo for rootless Podman.
brev/test-docker-compose.bash	Extends compose test harness to support Docker and Podman variants.
brev/prepare-podman-compose.py	Adds a converter to adapt ACH compose files for rootless Podman.
brev/generate-cscs-edf.bash	Adds EDF generator for CSCS Slurm Container Engine runs (optionally pinned tags).
brev/entrypoint.bash	Adjusts entrypoint to behave correctly for root and non-root (rootless) contexts.
brev/entrypoint-shell.bash	Handles user switching only when running as root.
brev/entrypoint-nsight.bash	Removes restart workaround logic from Nsight streamer entrypoint wrapper.
brev/entrypoint-jupyter.bash	Handles user switching only when running as root.
brev/entrypoint-base.bash	Handles user switching only when running as root.
brev/entrypoint-base-user.bash	Fixes test argument forwarding by splitting env var into an argv array.
brev/dev-test.bash	Updates documentation text to cover Docker/Podman compose.
brev/dev-stop.bash	Switches dev stop to use selected compose engine rather than hard-coded docker.
brev/dev-start.bash	Supports Podman dev start by using --no-build and adapted compose file.
brev/dev-shell.bash	Supports Podman dev shells (pull first; use prepared compose).
brev/dev-common.bash	Introduces container engine selection helpers and compose-file preparation.
brev/dev-build.bash	Uses selected compose engine for image builds.
.github/workflows/build-brev-tutorial-docker-images.yml	Enables event/** builds and switches to native per-arch build + manifest publish flow.

---

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[robobryce]

Fixed in #220. The top-level row now names the PyHPC tutorial and links to tutorials/pyhpc/README.md and its Docker Compose file. I also corrected its hardware guidance. The full link check reports 87 valid links and 0 errors.

[robobryce]

Fixed in #220. The direct reference is now one quoted pip argument (nsightful[notebook] @ git+https://…), and I corrected all six matching exercise/solution Colab cells. They now pin the same tested nsightful commit as the image requirements; all 26 notebook-format and install-consistency checks pass.

[robobryce]

Fixed in #220: swe_thrust_solver.cpp now includes <cmath>. CUDA 13.3 compile validation passes.

[robobryce]

Fixed in #220. cpp_step now accepts only 1-D, C-contiguous, CPU-resident double arrays with implicit conversion disabled; it validates equal lengths and the two-ghost-cell minimum before dereferencing. The exercise and solution notebook sources match, and compile/runtime guard tests pass.

[robobryce]

Fixed in #220. Both exercise and solution files are renamed to power_iteration, with the README, syllabus, and test ladder updated consistently. A repository search finds no remaining power_iteraiton references.

[brycelelbach]

We need instructions on how to deploy the container for 10 hours and connect to the JupyterLab, nsys, and ncu services from a web browser. Those instructions should mount the checked out repo so students solutions will persist. Add them to cscs.md

I have a feeling we'll need to do SSH port forwarding. Will that cause issues with the responsiveness/interactivity of the nsys/ncu services that use WebRTC?

[robobryce]

Implemented and live-tested in #220. docs/cscs.md now gives the checkout/update, 10-hour sbatch, browser tunnel, service URLs, reconnect, cancellation, and cleanup commands. The launcher pulls only the GitHub-CI tutorial image plus the NVIDIA Streamer images and bind-mounts the $SCRATCH checkout so student work persists.

The working tunnel forwards five ports: Jupyter HTTPS 8888; Nsight Systems HTTPS/signaling 8080 plus TURN/TCP 3478; and Nsight Compute HTTPS/signaling 8081 plus TURN/TCP 3479. The two TURN forwards are required for WebRTC video/input. TURN/TCP works through SSH, with the documented TCP-over-TCP responsiveness tradeoff on lossy links.

I tested from this node against Daint job 4258261 on nid006001: all three HTTPS applications loaded; both Streamers selected connected, nominated TURN/TCP relay pairs, opened their input data channels, and delivered advancing 1280x800 video with zero dropped frames in the samples. A file written through Jupyter HTTPS appeared in the bind-mounted $SCRATCH checkout. Graceful TERM cleanup removed containers, listeners, private TLS/TURN state, and job-local image stores while preserving student work.

[Copilot]

Pull request overview

Copilot reviewed 69 out of 73 changed files in this pull request and generated 5 comments.

[Copilot]

Pull request overview

Copilot reviewed 69 out of 73 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (2)

brev/generate-cscs-edf.bash:91

• generate-cscs-edf.bash shells out to docker compose ... config to read x-config values. That hard-requires a working Docker CLI/daemon even though this script is meant for CSCS/rootless environments where Podman is used. Since the repo already provides brev/dev-common.bash with setup_container_engine + compose, use those helpers here so the EDF generator works with either engine.

if [ -z "${IMAGE}" ] || [ -z "${WORKDIR}" ]; then
    COMPOSE_CONFIG=$(docker compose -f "${COMPOSE_FILE}" config --format json)
fi

tutorials/pyhpc/notebooks/swe_thrust_solver.cpp:36

• CUDA API calls here ignore return codes (cudaMallocManaged, cudaDeviceSynchronize, cudaFree), so allocation/sync failures can lead to undefined behavior or silent wrong results (especially since the output buffers are then copied back unconditionally). Add explicit cudaError_t checks (and ideally capture/report errors after the Thrust launches as well) so failures surface clearly to the Python caller.

[Copilot]

Pull request overview

Copilot reviewed 69 out of 73 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (2)

brev/generate-cscs-edf.bash:91

• This script shells out to docker compose ... config, which will fail on CSCS-style environments that intentionally lack a Docker daemon/client (but do have rootless Podman). Since the repo now provides brev/dev-common.bash helpers to select Docker vs Podman, use them here so EDF generation works in both environments.

if [ -z "${IMAGE}" ] || [ -z "${WORKDIR}" ]; then
    COMPOSE_CONFIG=$(docker compose -f "${COMPOSE_FILE}" config --format json)
fi

tutorials/pyhpc/notebooks/swe_thrust_solver.cpp:36

• cudaMallocManaged return codes are ignored. If any allocation fails, the function will dereference null pointers (or leak earlier allocations) and likely crash the notebook kernel. Check allocation status and clean up on failure so the error is handled predictably.