Re: Speed up clean meson builds by ~25%

Hi,

On 2024-04-05 15:36:34 +0200, Jelte Fennema-Nio wrote:
> On Fri, 5 Apr 2024 at 00:45, Jelte Fennema-Nio <me(at)jeltef(dot)nl> wrote:
> > It improved clean build times on my machine (10 cores/20 threads) from ~40
> > seconds to ~30 seconds.
>
> After discussing this off-list with Bilal, I realized that this gain
> is only happening for clang builds on my system. Because those take a
> long time as was also recently discussed in[1]. My builds don't take
> nearly as long though. I tried with clang 15 through 18 and they all
> took 10-22 seconds to run and clang comes from apt.llvm.org on Ubuntu
> 22.04
>
> [1]: https://www.postgresql.org/message-id/flat/CA%2BhUKGLvJ7-%3DfS-J9kN%3DaZWrpyqykwqCBbxXLEhUa9831dPFcg%40mail.gmail.com

I recommend opening a bug report for clang, best with an already preprocessed
input file.

We're going to need to do something about this from our side as well, I
suspect. The times aren't great with gcc either, even if not as bad as with
clang.

Greetings,

Andres Freund