Buildworld and buildkernel with very slow compilation, recently

[Yuri Pankov]

Michael Grimm wrote:
> Hi,
> 
> I am following FreeBSD 12.1-STABLE.
> 
> Clang has been upgraded to version 10.0.0 on May, 1st, and ever since that time, I do observe a dramatic increase in compilation times of building world, kernel and ports. I didn't benchmark the exact times, but compilation times are at least increased by a factor of 1.5. Nothing has changed of the last month besides upgrading 12.1-Stable every other week.

Not seeing this after clang update to 10 on both stable/12 and head. 
I'd check if you are excessively swapping now as (not sure about that, 
just guessing) newer clang/llvm could consume more memory during 
compilation, and possibly reducing the make jobs number.