jsonbench

Welcome to the jsonbench documentation.

Description

The purpose of this tool is to compare the performance of different JSON C/C++ libraries and to show what to expect from a possible alternative JSON processor.

Currently, mod_security2 and libmodsecurity3 use YAJL for JSON processing. Unfortunately, this library is deprecated and no longer maintained.

Supported JSON Engines

The tool currently supports the following JSON parsers:

• YAJL
• RAPIDJSON
• NLOHMANNJSON
• JSONC
• JANSSON
• CJSON
• JSONCPP
• JSONCONS
• SIMDJSON
• YYJSON
• GLAZE = It is only compatible with C++23 or newer and is therefore not entirely suitable for modsecurity as it is based on C++17.

You can list them via:

src/jsonbench -h

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Requirements

To compile the code, you need development packages (-dev) of the JSON libraries.

Install required packages (Debian/Ubuntu)

sudo apt install \
    libyajl-dev \
    rapidjson-dev \
    nlohmann-json3-dev \
    libjson-c-dev \
    libjansson-dev \
    libcjson-dev \
    libjsoncpp-dev \
    libsimdjson-dev \
    libyyjson-dev \
    libjsoncons-dev \
    libglaze-dev

Note:

• The -dev packages are required for compiling (headers, pkg-config, etc.)
• Runtime libraries (e.g. libjsoncpp26, libsimdjson25, etc.) are installed automatically

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Package availability note

Some packages depend on your distribution version.

Especially:

• libglaze-dev is only available in newer Linux distributions
• Older systems may not provide it

You can check availability with:

apt list | grep glaze

or

apt search libglaze-dev

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Header-only libraries

These parsers are header-only:

• RapidJSON (rapidjson-dev)
• nlohmann JSON (nlohmann-json3-dev)

They do not require linking against a library.

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Build

./autogen.sh
./configure 
make

./configure optionally with --with-all-json=yes. This option requires all supported JSON libraries to be available and causes configuration to fail if any are missing.

If you want to disable a parser:

./configure --with-yajl=no

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Run

Show help:

src/jsonbench -h

Run with a specific parser:

src/jsonbench -e YAJL

Example:

src/jsonbench -e SIMDJSON -s tests/test01.json

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Command line options

• -h Show help
• -e Select JSON engine
• -d Max depth (default: 500)
• -a Max arguments (default: 500)
• -n Number of timed iterations (default: 1); reports mean ± stddev across all runs
• -s Silent mode

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Example

Single run:

src/jsonbench -s -e YAJL -a 10000 tests/test06.json

Output:

Time: 0.000092567 sec

Multiple iterations (reports mean ± stddev):

src/jsonbench -s -n 20 -e SIMDJSON -a 10000 tests/test06.json

Output:

Time: mean=0.000091234 sec  stddev=0.000002345 sec  (N=20)

Run the test suite:

tests/run_tests.sh           # all available engines
tests/run_tests.sh SIMDJSON  # single engine

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TODO

• Improve documentation for all parsers
• Add more JSON processors