Disabling idle GC leads to freeze
I'm currently getting a runtime freeze with a spinning CPU with the latest GHC 8.0.1 RC (126.96.36.19960411). Testing 2 months ago on whatever was the latest release candidate showed no problems. The reproduction steps are a bit long winded:
- All tested on Ubuntu Linux.
- Checkout Shake, https://github.com/ndmitchell/shake.git (currently at 75505baa5fc5d1b99a1162edae6ecf7669f00ed9).
- Checkout Ninja, https://github.com/ninja-build/ninja.git (currently at 78f548880e549c701bd77760e4b3f3a4ee147641).
- Change to the
cp ninja nin
./nin -t clean
Observe that Shake fails to complete and starts spinning on 1 CPU.
If you modify
shake.cabal to remove
-with-rtsopts=-I0 -qg -qb then it works again and completes in < 1 min. Adding back flags with
+RTS -I0 -RTS shows that
-I0 alone is the culprit.