Remove OMP_NUM_THREADS if set to empty

[mrocklin]

Generally though, sometimes our use of OMP_NUM_THREADS makes other systems sad. It's unfortunately somewhat difficult to turn off. A common approach is that people set OMP_NUM_THREADS="" but this doesn't properly unset things.

I'm curious if an approach like this would be helpful.

There might be a cleaner way to do this, and this might be a bad idea. Please feel free to reject. It was just easy to put this up as a PR.

@ntabris would something like this make your life easier? @fjetter is this not dumb?

[ntabris]

would something like this make your life easier?

Not anytime soon but seems like a positive change to me.

[github-actions[bot]]

Unit Test Results

See test report for an extended history of previous test failures. This is useful for diagnosing flaky tests.

    27 files  ± 0      27 suites  ±0   11h 28m 55s ⏱️ - 2m 51s  4 117 tests + 1   4 000 ✅  - 5    111 💤 ±0   6 ❌ + 6  51 628 runs  +13  49 314 ✅  - 3  2 296 💤  - 2  18 ❌ +18 

For more details on these failures, see this check.

Results for commit b735ba0f. ± Comparison against base commit fd3722da.

:recycle: This comment has been updated with latest results.

[fjetter]

No objections. It appears to not be working, though. The test is failing (linter is also off)

[guillaumeeb]

I think this won't be relevant anymore if we confirm https://github.com/dask/distributed/pull/9081.