[beached_whale]

You can know where you time is going, at least with clang, by adding -ftime-report to your compiler command line. The headers take a long time is often that the compiler can do a better job at optimizing and inlining as everything is visible. Just timing your compiles is like trying to find things in the dark, you know the wall is there but what are you stepping on :) Good to know what is taking a long time, but it may not be the header itself but how much more work the compiler can do now to give a better output(potentially)

[fouronnes3]

I've been working with -ftime-report, but unfortunately it reports times per cpp file. I'm looking for a way to get a summary across an entire CMake build. Right now reading 100+ -ftime-report outputs is not really useful, although deep down I know it's all template instancing anyway.

[beached_whale]

When I look most of the time has gone to inline and optimization. But I only look sometimes and sample size is Me