I'm also surprised about the dontneed vs. munmap numbers.You mean the ones for Altra that I posted? (I didn't post any for M2). The altra numbers look ok to me; dontneed has no change, and munmap has no change for order-0 and is massively improved for order-9.
I would expect that dontneed would similarly benefit -- same code path. But I focused on munmap measurements for now, I'll try finding time to confirm that it's the same on Intel.
-- Cheers, David / dhildenb