Reduce memory usage in io proxy process

[dgud]

Heap grows a lot with large printouts and stays large, which causes problems when running in testcases in parallel, which keeps a lot of these processes around.

In my case the used memory went from 6.6GB to 500MB.

[github-actions]

CT Test Results

  2 files   57 suites   1h 16m 24s ⏱️
451 tests 438 ✅ 13 💤 0 ❌
485 runs  469 ✅ 16 💤 0 ❌

Results for commit b6e6804.

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[michalmuskala]

Have you tried changing the fullsweep_after setting of a process - this should force more frequent major GC too, without sprinkling the code with manual calls to GC

[dgud]

No didn't think of that, I had 20-30 of these 200MB processes that caused the 32b runs to crash with out of memory so
might have gone for the largest axe around, but these processes have almost no live data, so the fullsweep GC is cheap and in my case the overall time was slightly faster.
Changing to minor GC didn't help at all in this case.

But will try you suggestion before merging.

[dgud]

Yeah that didn't help that much, only down to ~3GB.