[lld] [lld][MachO]Multi-threaded i/o. 40% speedup linking a large project. (PR #147134)

[John Holdsworth via llvm-commits]

johnno1962 wrote:

The last commit was to also use the threaded page-in approach with the objects in archives. The last ten linking times were:

19.45, 15.43, 15.45, 13.43, 12.30, 12.98, 12.10, 15.35, 15.13, 15.69

Looking at process manager as it cycles repeatedly through a link I/o is now far more concentrated.

<img width="410" alt="image" src="https://github.com/user-attachments/assets/e455e5a3-4b20-44bd-a194-8f21e1f4c97c" />


https://github.com/llvm/llvm-project/pull/147134