Simple benchmark for a number of C++ JSON libraries.

List of currently measured libraries:

• casablanca - C++ REST SDK (codename "Casablanca")
• json_spirit
• jsoncpp
• libjson
• rapidjson

I created this benchmark driven by curiosity and for my own purposes, with hope to obtain useful and interesting results, for myself and others too. I do not have any objective of making ultimate performance shootout. This is not a rocket science, but a simple set of C++ programs, with likelyhood of bugs or inconsistencies. Found any, please report. Comments and improvements are always welcome!

Recorded are elapsed times of parsing/reading/consuming JSON string and constructing corresponding value object in memory of type as defined by interface of a particular library.

Single mark of elapsed time is collected for I iterations of P parsings. Each mark is repeated M times in order to obtain lowest and highest timing.

For example, if there are P JSON different strings loaded into test data container, and all strings are parsed I times, total elapsed time of all I x P parsings is measured; this is repeated M times.

There are two sets of JSON test data:

• large - single large JSON object
  • data/canada.json contains contour of Canada border in GeoJSON
• small - collection of small JSON objects:
  • data/one-json-per-line.jsons collection of 500 sample JSON strings from sub-100 to 500 characters long.

Note, all libraries are used to read and parse strings of narrow char characters (i.e. std::string), no wchar_t strings are used.

All timings obtained running optimised builds of the binaries.

• small

rapidjson.small:  2 marks of 1000 x 500 batch of parsings in 0.961858 to 0.962361 per batch
libjson.small:    2 marks of 1000 x 500 batch of parsings in 5.2787 to 5.29663 per batch
jsoncpp.small:    2 marks of 1000 x 500 batch of parsings in 5.762 to 5.77978 per batch
casablanca.small: 2 marks of 1000 x 500 batch of parsings in 17.7374 to 17.7587 per batch
spirit.small:     2 marks of 1000 x 500 batch of parsings in 22.137 to 22.137 per batch

• large

rapidjson.large:  2 marks of 1000 x 1 batch of parsings in 7.96621 to 7.97555 sec per batch
libjson.large:    2 marks of 1000 x 1 batch of parsings in 240.289 to 240.289 sec per batch

Notes:

• rapidjson was used in DOM parsing mode, not SAX
• libjson supports lazy parsing, times collected for this modes was:

libjson.small:    2 marks of 1000 x 500 batch of parsings in 0.478065 to 0.486636 per batch

TODO

Boost.Build configuration is provided and it assumes either your user-config.jam file has use-project entry for Boost (headers are required) and for every JSON library. For example:

use-project /boost : /home/mloskot/boost/trunk ;
use-project /json_spirit  : /home/mloskot/json_spirit ;

Alternatively, set the environment variables:

• BOOST_ROOT for Boost
• <LIBRARY_NAME>_ROOT for each library.

The environment variables can be passed directly on the Boost.Build invocation:

b2 -sBOOST_ROOT=/home/mloskot/boost/trunk -sJSON_SPIRIT_ROOT=/home/mloskot/json_spirit

and so on.

Or, simply edit Jamroot file.

In order to build the benchmark programs run:

b2 variant=release

Distributed under the Boost Software License, Version 1.0. See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.

Copyright 2013 Mateusz Loskot

and others (see copyright headers in source files).