Archives / 2014 / October
  • Json.NET 6.0 Release 6 - ASP.NET CoreCLR Support, Memory Usage Optimizations


    Json.NET now supports running on the ASP.NET CoreCLR, a coming soon server optimized CLR for running applications in the cloud.

    Today, you run ASP.NET using the same CLR that desktop apps use. We’re adding a cloud-optimized (my cloud, your cloud, their cloud - server stuff) version optimized for server scenarios like low-memory and high-throughput.

    ASP.NET vNext will let you deploy your own version of the .NET Framework on an app-by-app-basis. One app with new libraries can’t break an app next door with a different version. Different apps can even have their own cloud-optimized CLR of their own version. The CLR and cloud-optimized libraries are NuGet packages!

    Bin deploy ASP.NET to a Mac or Linux server? Sign. Me. Up. Find out more about the ASP.NET CoreCLR and ASP.NET vNext here.

    Memory Usage Optimizations

    This release of Json.NET optimizes memory usage, in particular heap allocations when reading and writing JSON.

    Json.NET has always been memory efficient, streaming the reading and writing large documents rather than loading them entirely into memory, but I was able to find a couple of key places where object allocations could be reduced. Deserialization saw the biggest improvement with about a 35% decrease in allocations. Less allocations, less garbage collection. Less garbage collection, more requests per second.

    The before memory timeline when deserializing a 5 megabyte JSON file:

    I have asked you nicely not to mangle my merchandise. You leave me no choice but to ask you nicely again.

    And the after timeline:

    I've gotten word that a child is using his imagination... and I've come to put a stop to it

    Grey is unmanaged memory, blue is the Gen0 heap, red is Gen1, green is Gen2 and the profiler used is dotMemory.

    For comparison, here is what JavaScriptSerializer looks like doing the same work:

    All my life I've been an obese man trapped inside a fat man's body.

    JavaScriptSerializer only works with strings so the purple here is a 5 megabyte string being loaded into the large object heap. After the latest optimizations Json.NET allocates 8 times less memory than JavaScriptSerializer.


    Here is a complete list of what has changed since Json.NET 6.0 Release 5.

    • New feature - Added support for ASP.NET CoreCLR
    • New feature - Reduced memory allocations when reading and writing JSON
    • New feature - Added support for passing arguments to JsonConverters with JsonConvertAttribute
    • New feature - Added JsonConvert.ToString overload that takes a StringEscapeHandling parameter
    • Change - Omit fields array for F# discriminated union serialization when there are no fields
    • Change - Escape property names in path on readers/writers/tokens when a name contains special characters
    • Change - Provide line numbers for end tokens on JTokenReader
    • Fix - Fixed parsing in SelectToken when the path has an escaped property followed by an unescaped property
    • Fix - Fixed error when deserializing a GUID from certain BSON
    • Fix - Fixed null reference error when using a JEnumerable created with its default constructor
    • Fix - Fixed line breaks in exception messages to use Environment.NewLine
    • Fix - Fixed MetadataTypeAttribute reflection error on ASP.NET CoreCLR
    • Fix - Fixed immutable collections reflection error on ASP.NET CoreCLR


    Json.NET GitHub Project

    Json.NET 6.0 Release 6 Download - Json.NET source code and assemblies