James Newton-King
1fa5e4a22e
-Fixed potential null reference error when getting attributes -Performance documentation
84 lines
4.8 KiB
XML
84 lines
4.8 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<topic id="Performance" revisionNumber="1">
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<developerConceptualDocument xmlns="http://ddue.schemas.microsoft.com/authoring/2003/5" xmlns:xlink="http://www.w3.org/1999/xlink">
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<introduction>
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<para>Out of the box Json.NET is faster than DataContractJsonSerializer and JavaScriptSerializer.
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Here are some tips to make it go even faster.</para>
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</introduction>
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<section>
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<title>Optimize Memory Usage</title>
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<content>
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<para>To keep an application consistantly fast it is important to minimize the
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amount of time the .NET framework spends performing <externalLink>
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<linkText>garbage collection</linkText>
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<linkUri>http://msdn.microsoft.com/en-us/library/ms973837.aspx</linkUri>
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<linkTarget>_blank</linkTarget>
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</externalLink>.
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Allocating too many objects, or allocating very large objects can slow down or even
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halt an application while garbage collection is in progress.
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</para>
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<para>To minimize memory usage and the number of objects allocated Json.NET supports
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serializing and deserializing directly to a stream. Reading or writing JSON a piece at a time instead of having
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the entire JSON string loaded into memory is especially important when working with JSON
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documents greater than 85kb in size to avoid the JSON string ending up in the <externalLink>
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<linkText>large object heap</linkText>
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<linkUri>http://msdn.microsoft.com/en-us/magazine/cc534993.aspx</linkUri>
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<linkTarget>_blank</linkTarget>
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</externalLink>.</para>
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<code lang="cs" source="..\Src\Newtonsoft.Json.Tests\Documentation\PerformanceTests.cs" region="DeserializeString" title="Deserialize String" />
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<code lang="cs" source="..\Src\Newtonsoft.Json.Tests\Documentation\PerformanceTests.cs" region="DeserializeStream" title="Deserialize Stream" />
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</content>
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</section>
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<section>
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<title>JsonConverters</title>
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<content>
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<para>Passing a <codeEntityReference>T:Newtonsoft.Json.JsonConverter</codeEntityReference> to SerializeObject or DeserializeObject provides a simple way to completely
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change how an object is serialized. There is however a small overhead; the CanConvert method is called for every
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type to check whether serialization should be handled by that JsonConverter.</para>
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<para>There are a couple of ways to continue to use JsonConverters without any overhead. The simplest way
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is to specify the JsonConverter using the <codeEntityReference>T:Newtonsoft.Json.JsonConverterAttribute</codeEntityReference>. This attribute tells the serializer
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to always use that converter when serializing and deserializing the type, without the check.</para>
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<code lang="cs" source="..\Src\Newtonsoft.Json.Tests\Documentation\PerformanceTests.cs" region="JsonConverterAttribute" title="Use JsonConverter with JsonConverterAttribute" />
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<para>If the class you want to convert isn't your own and you're unable to use an attribute a JsonConverter can still be used by
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creating your own <codeEntityReference>T:Newtonsoft.Json.Serialization.IContractResolver</codeEntityReference>.</para>
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<code lang="cs" source="..\Src\Newtonsoft.Json.Tests\Documentation\PerformanceTests.cs" region="JsonConverterContractResolver" title="Use JsonConverter with IContractResolver" />
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<para>The IContractResolver in the example above will set all DateTimes to use the JavaScriptDateConverter.</para>
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</content>
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</section>
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<section>
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<title>Manually Serialize</title>
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<content>
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<para>The absolute fastest way to read and write JSON is to use JsonTextReader and JsonTextWriter directly. Using a reader or writer
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directly skips any of the overhead from a serializer such as reflection.</para>
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<code lang="cs" source="..\Src\Newtonsoft.Json.Tests\Documentation\PerformanceTests.cs" region="ReaderWriter" title="Manually serialize using JsonTextWriter" />
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<para>If performance is important and you don't mind more code to get it then this is your best choice.</para>
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</content>
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</section>
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<section>
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<title>Benchmarks</title>
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<content>
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<mediaLink>
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<image class="image" xlink:href="performance" mimeType="image/png" width="643" height="345" />
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<summary>Json.NET Performance</summary>
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</mediaLink>
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</content>
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</section>
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<relatedTopics>
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<codeEntityReference>T:Newtonsoft.Json.JsonSerializer</codeEntityReference>
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<codeEntityReference>T:Newtonsoft.Json.JsonConverter</codeEntityReference>
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<codeEntityReference>T:Newtonsoft.Json.JsonConverterAttribute</codeEntityReference>
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<codeEntityReference>T:Newtonsoft.Json.JsonTextWriter</codeEntityReference>
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<codeEntityReference>T:Newtonsoft.Json.JsonTextReader</codeEntityReference>
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</relatedTopics>
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</developerConceptualDocument>
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</topic> |