The Performance Impact Of GCC CPU Tuning On The Linux Kernel's Performance

In the end, the upstream kernel developers are largely right that the "-march=" tuning really doesn't help out.

In the various OpenGL graphics benchmarks run on Radeon GPUs as well as the Core i7 8086K with UHD Graphics, there wasn't much change though the more powerful systems with Radeon discrete graphics did have a very slight gain performance for some of the games.

In total, 79 benchmarks were run on both kernels on all four systems. When taking the geometric mean of all the results, all four systems show the outcome of the "-march=" tuning overall as dead-flat compared to the stock kernel. So the testing didn't end up being all that exciting and largely jives with what has been said by the upstream kernel developers, though if anyone is interested in the entire data-set they can find it via OpenBenchmarking.org.