[PATCH] D124715: Use QoS class Utility for ThreadPriority::Low on Mac

Tue May 3 07:53:57 PDT 2022

sammccall added a comment.

> With this priority, the thread is
> confined to efficiency cores only, which makes background indexing take forever

(How) does this interact with battery vs mains power on laptops?
It seems like there's a common scenario where:

- the user is on a relatively slow laptop, running off battery
- the codebase is large, and indexing is unlikely to finish within an editing session

In this case, it seems like only using efficiency cores is what you'd want, and that people are likely to be upset if clangd 15 keeps their performance cores running at all times.

Reading the docs <https://developer.apple.com/library/archive/documentation/Performance/Conceptual/power_efficiency_guidelines_osx/PrioritizeWorkAtTheTaskLevel.html> it seems like background is the intended QoS for this type of work ("such as indexing"..."minutes or hours").

(Sorry to bring this up at code review time, I wasn't thinking about laptops when we discussed on the bug)

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124715/new/

https://reviews.llvm.org/D124715