Modern Intel CPUs I am led to believe that issuing nops is actually slower than adding prefixes. I think there is work in the backend updating retired instructi

Modern Intel CPUs I am led to believe that issuing nops is actually slower than adding prefixes. I think there is work in the backend updating retired instruction counters and other state which still occurs for nops, but decoding prefixes happens entirely in the front end. When a nop truly is necessary you will see compilers and performance engineers add prefixes to the nop to make it the desired size.