On Tue, 7 Feb 2023 10:30:24 +0200 Κρακ Άουτ <krack...@gmx.com> wrote:
Dear Κρακ, > I have compiled dwm & st using -march=x86-64-v3 (tried > -march=x86-64-v2 also). To be honest they are both (dwm & st) fast > and snappy with their default configuration and I cannot spot any > difference when compiled with -march=x86-64-v3 or v2. Is there any > point adding them? > > Related, would -O2 or -O3 flags give any benefit? > > As I mentioned, in practice I don't see any differences. I'm > wondering if theoretically there could be some positive effect. > People who know how exactly the code works are better suited to > supply a definitive answer than me, that's why I'm posting here. what Petr and Roberto said, but also: The -Os flag (i.e. go for smallest size) often yields more performant code than -O2 or -O3. As a general note: I found the use of efficent and smart data structures to always be the best way to dramatically speed up code. It's very inconsistent to rely on "smart" optimizations by the compiler, and even though they can go very far, they can rarely beat well-thought-out data structures. With best regards Laslo
