PGO not only for own code but for D runtime & Phobos too?

[Jon Degenhardt]

On Thursday, 3 October 2019 at 15:15:44 UTC, Robert M. Münch 
wrote:
> Did anyone already try to use PGO with his own code and for the 
> D runtime and phobos?
>
> Any indication how big the performance difference is when the D 
> runtime and Phobos is compiled using PGO?

I did a study of LTO and PGO on the combined application and 
libraries (druntime & phobos). It's available here: 
https://github.com/eBay/tsv-utils/blob/master/docs/lto-pgo-study.md.

For the apps tested it's a big win to include druntime and phobos 
in the LTO/PGO target. PGO makes a difference standalone, though 
I didn't try to separate the app code from the druntime/phobos 
code.

--Jon