Comment by 8n4vidtmkvmk
4 days ago
Doesn't capn proto win hands down on compute?
I haven't used it, but I thought that was the big claim.
4 days ago
Doesn't capn proto win hands down on compute?
I haven't used it, but I thought that was the big claim.
Not necessarily.
Cap'n Proto serialization can be a huge win in terms of compute if you are communicating using shared memory or reading huge mmaped files, especially if the reader only cares to read some random subset of the message but not the whole thing.
But in the common use case of sending messages over a network, Cap'n Proto probably isn't a huge difference. Pushing the message through a socket is still O(n), and the benefits of compression might outweigh the CPU cost. (Though at least with Cap'n Proto, you have the option to skip compression. Most formats have some amount of compression baked into the serialization itself.)
Note that benchmarks vary wildly depending on the use case and the type of data being sent, so it's not really possible to say "Well it's N% faster"... it really depends. Sometimes Protobuf wins! You have to test your use case. But most people don't have time to build their code both ways to compare.
I actually think Cap'n Proto's biggest wins are in the RPC system, not the serialization. But these wins are much harder to explain, because it's not about speed, but instead expressiveness. It's really hard to understand the benefits of using a more expressive language until you've really tried it.
(I'm the author of Cap'n Proto.)