[WIP] Only run writer close test once

[orionr]

This had some issues in our internal PyTorch testing infrastructure.

[lanpa]

The loop was added intentionally. What is the issue?

[orionr]

I'm not 100% sure this solves the issue (still testing internally) but we have some internal stress tests that fail on this test with the loop. I still need to verify this fixes the issue, but can you explain the reason for having the loop? Was this essentially a stress test?

[lanpa]

#108

I remember that I tried to fix this long time ago and suspected that it might be related to python's GIL.
The maximum open/close allowed are different on different OS.

[orionr]

That's possible. Just landed internal changes to see if this fixes the issue we were seeing or not. I'll report back.

[orionr]

Looks like this did fix the internal case. It's possible that we could have a few loops, but the large number was definitely an issue.

[lanpa]

Yeah, I believe it needs a major rewrite with the multiprocessing module.