[None] [doc] Document hang issue caused by UnpicklingError
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Signed-off-by: Kaiyu Xie <[email protected]>
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📝 WalkthroughWalkthroughDocumentation update to examples/wide_ep/README.md adding troubleshooting notes about an UnpicklingError related to MPI, including context, current stance, and guidance; note appears twice adjacent to manual cleanup guidance. Changes
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128-135: Tighten language, clarify scope, and add actionable guidance for users hitting UnpicklingErrorCurrent text is speculative (“seems to be existing in MPI”), grammatically rough, and lacks concrete next steps. Recommend a concise “Known issue” block with scope, detection, temporary workarounds, and status, plus neutral wording. Example patch:
-### Hang issue caused by `UnpicklingError` - -It's possible to see hang issue that is caused by an `UnpicklingError`, we've noticed that and recorded it as a known issue. The issue seems to be existing in MPI, because we are not reproducing again after by-passing the MPI route by implementing customized InfiniBand communicator and replacing MPI API calls with that. We did not proceed because: -1. The implementation only works on InfiniBand, hence not general enough. -2. The implementation largely duplicated with InfiniBand communicator implementation in NCCL, which is hard to maintain. - -That being said, we are aware of the `UnpicklingError`, but instead of pushing further, we decided to keep observing for a while to see if it would be gone with further 3rd-party dependency upgrade. Please let us know if it's a blocker in your workload, and we will do necessary adjustment based on the feedback. +### Known issue: potential hang with `UnpicklingError` + +You may encounter a hang preceded by an `UnpicklingError`. We have tracked this as a known issue. + +- Suspected scope: observed when using an MPI-based path. We were unable to reproduce the hang after bypassing MPI via a custom InfiniBand communicator that replaced MPI API calls. +- Why we did not adopt that workaround: (1) it only works on InfiniBand and is not general; (2) it duplicates functionality already implemented by NCCL, making it hard to maintain. + +What you can do: +- If this blocks your workload, please open a GitHub issue with logs (including the full `UnpicklingError` message and stack), MPI flavor/version, UCX/transport settings, and cluster/network details. +- If possible, try an environment without MPI for this path, or adjust to a configuration that avoids the MPI route. + +Status: +- We are monitoring upstream/dependency updates and will revisit once a robust, maintainable mitigation is available.Also consider linking to an issue ID tracking this known problem to centralize updates.
Please confirm MPI flavors/versions affected and add a link to the tracking issue so users can subscribe.
76-76: Spelling nit: use “Troubleshooting” in the headerChange “## Trouble shooting” to “## Troubleshooting” for consistency with common docs style.
-## Trouble shooting +## Troubleshooting
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