last time i benchmarked msgpack and protobuf against each other it was near flat for my use case. JSON was 2-3x slower, but msgpack and protobuf were near equal. might be different now after this release, exciting :)

Keep in mind that some of the performance bottlenecks the author is talking about and optimizing for show up in large-scale uses and possibly not in benchmarks. In particular, the "parsing too many different types blows away your instruction cache" issue will only show up if you are actually parsing lots of types, otherwise UPB is not necessary.