pytest-dev / pytest-dev/pytest-xdist

On long batches of tests, nodes stop getting assigned tasks

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#278 6 comments 0 reactions 0 assignees View on GitHub

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bug help wanted needs information
Dominant language
Python
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Description

I've been working on tests with fixtures. It generated ~10,000 tests that I split among 35 cores. The closer it gets to 100% complete, the fewer cores are actually working. At 97% I only had 20 cores running. At 98% there were 8 cores. Now I'm at 99% with 3 cores running.

It looks like this might be happening when two nodes report back near-simultaneously, but I don't know what the root cause is.

What can I do to find out what's going on?

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First steps

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Research direction

No files or tests are named. Start by reproducing the long fixture-generated batch across 35 cores and inspect task assignment and near-simultaneous node reports; done means the cause of workers becoming idle is identified and covered by a regression test.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
distributed-systems, testing
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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