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@ -11,12 +11,11 @@ simdjson : Parsing gigabytes of JSON per second
<img src="images/logo.png" width="10%" style="float: right">
JSON is everywhere on the Internet. Servers spend a *lot* of time parsing it. We need a fresh
approach. The simdjson library uses commonly available SIMD instructions and microparallel algorithms
to parse JSON 2.5x faster than RapidJSON and 25x faster than JSON for Modern C++.
to parse JSON 4x faster than RapidJSON and 25x faster than JSON for Modern C++.
* **Fast:** Over 2.5x faster than commonly used production-grade JSON parsers.
* **Fast:** Over 4x faster than commonly used production-grade JSON parsers.
* **Record Breaking Features:** Minify JSON at 6 GB/s, validate UTF-8 at 13 GB/s, NDJSON at 3.5 GB/s.
* **Easy:** First-class, easy to use and carefully documented APIs.
* **Beyond DOM:** Try the new On Demand API for twice the speed (>4GB/s).
* **Strict:** Full JSON and UTF-8 validation, lossless parsing. Performance with no compromises.
* **Automatic:** Selects a CPU-tailored parser at runtime. No configuration needed.
* **Reliable:** From memory allocation to error handling, simdjson's design avoids surprises.
@ -85,44 +84,16 @@ Usage documentation is available:
Performance results
-------------------
The simdjson library uses three-quarters less instructions than state-of-the-art parser [RapidJSON](https://rapidjson.org) and
fifty percent less than sajson. To our knowledge, simdjson is the first fully-validating JSON parser
The simdjson library uses three-quarters less instructions than state-of-the-art parser [RapidJSON](https://rapidjson.org). To our knowledge, simdjson is the first fully-validating JSON parser
to run at [gigabytes per second](https://en.wikipedia.org/wiki/Gigabyte) (GB/s) on commodity processors. It can parse millions of JSON documents per second on a single core.
The following figure represents parsing speed in GB/s for parsing various files
on an Intel Skylake processor (3.4 GHz) using the GNU GCC 9 compiler (with the -O3 flag).
We compare against the best and fastest C++ libraries.
on an Intel Skylake processor (3.4 GHz) using the GNU GCC 10 compiler (with the -O3 flag).
We compare against the best and fastest C++ libraries on benchmarks that load and process the data.
The simdjson library offers full unicode ([UTF-8](https://en.wikipedia.org/wiki/UTF-8)) validation and exact
number parsing. The RapidJSON library is tested in two modes: fast and
exact number parsing. The sajson library offers fast (but not exact)
number parsing and partial unicode validation. In this data set, the file
sizes range from 65KB (github_events) all the way to 3.3GB (gsoc-2018).
Many files are mostly made of numbers: canada, mesh.pretty, mesh, random
and numbers: in such instances, we see lower JSON parsing speeds due to the
high cost of number parsing. The simdjson library uses exact number parsing which
is particular taxing.
<img src="doc/gbps.png" width="90%">
On a Skylake processor, the parsing speeds (in GB/s) of various processors on the twitter.json file are as follows, using again GNU GCC 9.1 (with the -O3 flag). The popular JSON for Modern C++ library is particularly slow: it obviously trades parsing speed for other desirable features.
| parser | GB/s |
| ------------------------------------- | ---- |
| simdjson | 2.5 |
| RapidJSON UTF8-validation | 0.29 |
| RapidJSON UTF8-valid., exact numbers | 0.28 |
| RapidJSON insitu, UTF8-validation | 0.41 |
| RapidJSON insitu, UTF8-valid., exact | 0.39 |
| sajson (insitu, dynamic) | 0.62 |
| sajson (insitu, static) | 0.88 |
| dropbox | 0.13 |
| fastjson | 0.27 |
| gason | 0.59 |
| ultrajson | 0.34 |
| jsmn | 0.25 |
| cJSON | 0.31 |
| JSON for Modern C++ (nlohmann/json) | 0.11 |
number parsing.
<img src="doc/rome.png" width="90%">
The simdjson library offers high speed whether it processes tiny files (e.g., 300 bytes)
or larger files (e.g., 3MB). The following plot presents parsing
@ -132,7 +103,6 @@ speed for [synthetic files over various sizes generated with a script](https://g
[All our experiments are reproducible](https://github.com/simdjson/simdjson_experiments_vldb2019).
You can go beyond 4 GB/s with our new [On Demand API](https://github.com/simdjson/simdjson/blob/master/doc/ondemand.md).
For NDJSON files, we can exceed 3 GB/s with [our multithreaded parsing functions](https://github.com/simdjson/simdjson/blob/master/doc/parse_many.md).