> Never ever build in '-03 -march=native' by default. This is always a red flag and a sign of immaturity.
replyPerhaps you can see how there are some assumptions baked into that statement.
What assumptions would that be?
replyShipping anything built with -march=native is a horrible idea. Even on homogeneous targets like one of the clouds, you never know if they'll e.g. switch CPU vendors.
The correct thing to do is use microarch levels (e.g. x86-64-v2) or build fully generic if the target architecture doesn't have MA levels.
The only time I used -march=native was for a university assignment which was built and evaluated on the same server, and it allowed juicing an extra bit of performance. Using it basically means locking the program to the current CPU only.
replyHowever I'm not sure about -O3. I know it can make the binary larger, not sure about other downsides.
Not assumptions, experience.
replyI fully concur with that whole post as someone who also maintained a C++ codebase used in production.
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reply> -march=native is always always a mistake
replyGentoo user: hold my beer.
It's also an option on NixOS but I haven't managed to get it working unlike Gentoo.
replyGentoo binaries aren't shipped that way
reply>15000
reply15000 what?
1500 C/C++ individual software components.
replyThe 15000 was a typo on my side. Fixed.
I see, thanks. I didn't mind the number it just wasn't clear what was it about.
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