On Friday 2022-06-10 10:17, David Laight wrote:

quoted

Calling a "printf" style function is already insanely expensive. :-) I
understand that it's not okay blithely to increase runtime resources
simply because it's already slow, but in this case it's worthwhile.

Yep, IMHO definitely should be fixed.
It is even possible that using "%s" is faster because the printf
code doesn't have to scan the string for format effectors.

I see no special handling; the vsnprintf function just loops
over fmt as usual and I see no special casing of fmt by
e.g. strcmp(fmt, "%s") == 0 to take a shortcut.