Comment by MrDarcy
9 hours ago
TIL serializing a protobuf is only 5 times slower than copying memory, which is way faster than I thought it’d be. Impressive given all the other nice things protobuf offers to development teams.
9 hours ago
TIL serializing a protobuf is only 5 times slower than copying memory, which is way faster than I thought it’d be. Impressive given all the other nice things protobuf offers to development teams.
I guess that number is as good or as bad as you want with the right nesting.
Protobuf is likely really close to optimally fast for what it is designed to be, and the flaws and performance losses left are most likely all in the design space, which is why alternatives are a dime a dozen.
5x is pretty slow honestly. Imagine anything happening 5x as slow as you'd expect it to. I mean, for a recent project I had to inline Rust structs rather than parsing JSON too for specific fields, and that definitely sped it up.
Serializing a protobuf can be significantly faster than memcpy, depending. If you have a giant vector of small numbers represented with wide types (4-8 bytes in the machine) then the cost of copying them as variable-length symbols can be less.
that actually crazy fast
I wouldn't hold onto that number as any kind of fixed usable constant since the reality will depend entirely on things like cache locality and concurrency, and the memory bandwidth of the machine you're running on.
Go around doing this kind of pointless thing because "it's only 5x slower" is a bad assumption to make.