TLDR -- PGO reduces build times by 10-16% but is not straightforward to realize in CI.
Why isn't it straightforward, isn't autofdo automating the process?
> Unfortunately, bringing these improvements to end users is not as simple as adding a few compiler flags to our dist builds. PGO is different from most other optimizations in that it:
- requires a different, extended build workflow due to the additional instrumentation and data collection phases, and
- it incurs a sustained build time cost (a trait it shares with other automated optimizations like LTO).
Autofdo if automatically called by the rust toolchain should alleviate the first point
https://github.com/google/autofdo
(though it only work on Linux)
How much percent slower is the build time with PGO on average?