json-performance Reference

Script defined in lua/console/json-performance.lua. Comprehensive serialization performance benchmark comparing JSON, lpack, lpack binary, and string.buffer encode/decode speeds.

Functions/Exports

No module exports (standalone script). Contains the following local helper functions that run sequentially:

test() (local)

Main orchestrator - discovers .jbeam files, reads them, runs JSON decode benchmark, then calls each serialization test function.

testLpackEncode() (local)

Benchmarks lpack.encode() on all parsed tables, reports packed size and MB/s throughput.

testLpackDecode() (local)

Benchmarks lpack.decode() on lpack-encoded data, reports MB/s throughput.

testLpackEncodeBin() (local)

Benchmarks lpack.encodeBin() (binary variant), reports packed size and MB/s.

strbufEncode() (local)

Benchmarks LuaJIT string.buffer encode on all parsed tables, reports packed size and MB/s.

strbufDecode() (local)

Benchmarks string.buffer decode, reports MB/s throughput.

Tests Performed

1. File discovery - finds all *.jbeam files in /vehicles
2. File reading - reads all files into memory, reports size and throughput (MB/s)
3. JSON decode - parses all jbeam files 6x, measures throughput
4. lpack encode - encodes parsed Lua tables to lpack format, reports compressed size and throughput
5. lpack decode - decodes lpack data back, measures throughput
6. lpack encodeBin - binary variant of lpack encoding
7. lpack decodeBin - decodes binary lpack
8. string.buffer encode - LuaJIT string.buffer serialization
9. string.buffer decode - string.buffer deserialization

Configuration

• reruns = 6 - number of iterations for each test

Usage

beamng -console lua/console/json-performance.lua

Internal Notes

• Uses HighPerfTimer for precise measurements
• Reports MB/s throughput for each serialization method
• Calls collectgarbage() before each test for clean measurements
• Compares 4 serialization formats: JSON, lpack, lpack binary, string.buffer
• Reports total packed sizes to compare compression ratios
• JIT toggle is commented out but available for testing JIT impact