[PATCH] D73010: [llvm-lto2] By default, use two threads for ThinLTO backend.

[Yuanfang Chen via Phabricator via llvm-commits]

ychen added a comment.

@MaskRay @mehdi_amini I have no clue either on how this does not happen before. Adding `std::__throw_system_error` in ThreadPool ctor and reverting this change, I still see the crash in my machine (Ubuntu 18.04). I'm inclined to think the exception did not trigger before rather than it was triggered but somehow muted in some way.

FYI, besides the problem this change wanted to address, D67847 <https://reviews.llvm.org/D67847> also triggered a random host compiler crash on PPC64be bots.
http://lab.llvm.org:8011/builders/clang-ppc64be-linux/builds/43016/steps/build%20stage%201/logs/stdio

Both issues are related to system resource constraints. But how they are related to D67847 <https://reviews.llvm.org/D67847> remains a mystery to me. PPC64 bots admin said they are willing to help diagnosing these issues.

Do you think this change is worthwhile in general? I don't think any tests are relying on the number of backend threads and using less resources should be beneficial.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D73010/new/

https://reviews.llvm.org/D73010