Comparing against other serialization solutions, running on Windows 7 64bit. We use the LITE runtime for Protocol Buffers (less code / lower overhead), Rapid JSON (one of the fastest C++ JSON parsers around), and pugixml, also one of the fastest XML parsers.
We also compare against code that doesn't use a serialization library at all (the column “Raw structs”), which is what you get if you write hardcoded code that just writes structs. This is the fastest possible, but of course is not cross platform nor has any kind of forwards / backwards compatibility.
We compare against Flatbuffers with the binary wire format (as intended), and also with JSON as the wire format with the optional JSON parser (which, using a schema, parses JSON into a binary buffer that can then be accessed as before).
The benchmark object is a set of about 10 objects containing an array, 4 strings, and a large variety of int/float scalar values of all sizes, meant to be representative of game data, e.g. a scene format.
|FlatBuffers (binary)||Protocol Buffers LITE||Rapid JSON||FlatBuffers (JSON)||pugixml||Raw structs|
|Decode + Traverse + Dealloc (1 million times, seconds)||0.08||302||583||105||196||0.02|
|Decode / Traverse / Dealloc (breakdown)||0 / 0.08 / 0||220 / 0.15 / 81||294 / 0.9 / 287||70 / 0.08 / 35||41 / 3.9 / 150||0 / 0.02 / 0|
|Encode (1 million times, seconds)||3.2||185||650||169||273||0.15|
|Wire format size (normal / zlib, bytes)||344 / 220||228 / 174||1475 / 322||1029 / 298||1137 / 341||312 / 187|
|Memory needed to store decoded wire (bytes / blocks)||0 / 0||760 / 20||65689 / 4||328 / 1||34194 / 3||0 / 0|
|Transient memory allocated during decode (KB)||0||1||131||4||34||0|
|Generated source code size (KB)||4||61||0||4||0||0|
|Field access in handwritten traversal code||typed accessors||typed accessors||manual error checking||typed accessors||manual error checking||typed but no safety|
|Library source code (KB)||15||some subset of 3800||87||43||327||0|
Code for these benchmarks sits in
benchmarks/ in git branch
benchmarks. It sits in its own branch because it has submodule dependencies that the main project doesn't need, and the code standards do not meet those of the main project. Please read
benchmarks/cpp/README.txt before working with the code.