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I experiment some problems with rustc 1.12.0 (under OpenBSD):
- when builded with system LLVM 3.8.1 : seems ok
- when builded with system LLVM 3.9.0 (with additionnal patch rL281650 for ICE: void llvm::Value::replaceAllUsesWith(llvm::Value*): Assertion `!contains(New, this) && "this->replaceAllUsesWith(expr(this)) is NOT valid!"' failed. #36474) : problems
- when builded with embedded LLVM: still problems
There are two kind of problems:
- performance regression from stable to stable : I saw lot of
xxx has been running for over 60 secondsmessages in make check - occasionnally rustc compiler dead-lock: all threads are in
thrsleestate.
For the performance problem, by tracing the syscalls I saw lot of __thrsleep(), __thrwakeup() and sched_yield() dance: the process makes high usage of thread-syscalls, and it slows down.
Some stats for 1 second, I have 16314 syscalls:
- 7344 __thrwakeup
- 7343 __thrsleep
- 1605 sched_yield
- 11 mmap
- 4 write
- 4 mquery
- 2 munmap
- 1 fstat
For this second, by thread:
- thread 1031567:
- 1850 __thrsleep
- 1850 __thrwakeup
- 443 sched_yield
- thread 1048099
- 1848 __thrsleep
- 1848 __thrwakeup
- 298 sched_yield
- thread 1056179:
- 1844 __thrsleep
- 1844 __thrwakeup
- 483 sched_yield
- 4 write
- 3 mmap
- 2 mquery
- 1 munmap
- 1 fstat
- thread 1065035:
- 1801 __thrsleep
- 1802 __thrwakeup
- 381 sched_yield
- 8 mmap
- 2 mquery
- 1 munmap
I am unsure about the way to better describe the problem or reduce it.
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