performance compare in-interface vs src-mac-address

Lets assume we have a mangle rule which we can use in-interface or src-mac-address in it . i want to know which one is lighter and better to use for routeros performance .
Thanks

I think, than src-mac is not lighter: it’s 6 bytes long, and interface id is 4 bytes long =) so either it’s slower, or the same. I think, you won’t see any difference…