https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81616
--- Comment #17 from Andrew Roberts <andrewm.roberts at sky dot com> --- The general consensus in userland is that the znver1 optimization is much worse than 0.5%, or even 2% off. Most people are using -march=haswell if they care about performance. Just taking one part of one of my apps I see a 5% difference with -march=haswell vs -march=znver1, and this is just general code (loading GL extensions). The trick is to remove system dependencies from things I could benchmark. If there are no recommendations, I'll come up with some tests myself for various workloads, and try across various march/tune combos. I'll also look at some other real world benchmarks that are available online.
