try to debug crash on CI

[Guest0x0]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 166

Details

• 3 of 9 (33.33%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.5%) to 80.769%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/internal/event_loop/event_loop.mbt	3	9	33.33%

Totals
Change from base Build 162:	-0.5%
Covered Lines:	693
Relevant Lines:	858

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💛 - Coveralls

[Guest0x0]

close via #40. The actual cause is a bug in MacOS's signal implementation, and there is no way to work around the bug. Now the runtime uses condition variable for thread wake up on MacOS. Interestingly, condition variable is also buggy on MacOS. Fortunately the condition variable bug can be worked around.

On Linux, the runtime still uses signal, for smaller overhead, and the condition variable implementation of glibc seems to be buggy too.