[PATCH] D27715: libcxx std::condition_variable::wait_for() fix for when tick occurs during wait_for()

[Brian Cain via Phabricator via llvm-commits]

bcain added a comment.

In https://reviews.llvm.org/D27715#631540, @EricWF wrote:

> Also I would love to see an attempt at writing a test for this.


This was encountered on Hexagon.  thread.condition.condvar/wait_for detects the failure, so to some extent a test already exists.  I suspect that linux x86_64 would see the failure on that test if CONFIG_HZ were specified to be extremely high (> 40000).

An isolated, reliably failing test seems difficult/impossible since it would require the test case to simulate a system that knows quite a bit about the implementation ("system clock was just sampled in the wait_for context, so let's trigger a tick interrupt now").  A test case like this could be constructed but it would be a real challenge to integrate into the existing lit test suite.


Repository:
  rL LLVM

https://reviews.llvm.org/D27715