Few years back, i actually compared the three serializations, for the data i used ironically raw struct came on top for every benchmark https://cloudef.pw/protobug.png
This matches my experience as well. You should probably add code size to the graphs. Raw struct probably wins there too.
The only thing I’ve seen that’s competitive to raw struct is writing a C++ template visitor style pattern to walk the struct fields using inline methods. (This can be achieved in some other compiled languages, of course.)
It lets you compress things as you walk the struct, and breaks the dependency on struct layout (which can matter for cross-platform stuff, and for versioned protocols). It’s not quite as fast as a memcpy off the network buffer, but it can be branch and virtual dispatch free (not counting branches in the compression logic).
Also, it can validate as it copies the data into the struct, so now you can auto-generate application-specific validation logic. This is a big deal, since validating the output of a deserializer is almost as hard as hand deserialization!
I really liked the article however. Forcing tail optimization in the c++ template serializer sounds like it will substantially improve the (worst case) generated assembly.
