Question

We are using WCF for transferring data from a server application to several clients. Actually, for most of the traffic, client and server are running on the same machine, so I would expect the transfer to be really fast.

However, when transferring large arrays (16-bit grayscale images), it takes several seconds until the data is transferred. For a 16 MB image, it takes around 3-5 seconds!

Initially, we were using ushort arrays because it is the most suitable data type for storing 16-bit grayscale image data. However, this was extremely slow: something around 20-25 seconds for 16 MB. When we copy the data to a byte array before serialization using Buffer.BlockCopy, it is reduced to 3-5 seconds for some reason. However, 3-5 seconds for transferring 16 MB from one application to another running on the same machine still seems far too long to me!

Therefore, my question is: How can we improve the performance for such a scenario?

I already investigated protobuf-net from Marc Gravell, but I am uncertain whether it would help in this case… Any experiences or other suggestions?

Here is the source code of one of our data classes (containing the image data):

[DataContract(IsReference = true)]
public class ImageData
{
    private ushort[] m_pixelData;

    public ushort[] PixelData
    {
        get
        {
            return m_pixelData;
        }
        set
        {
            m_pixelData = value;
            OnPropertyChanged("PixelData");
        }
    }

    [DataMember]
    public override byte[] FileData
    {
        get
        {
            if (this.PixelData == null)
            {
                return null;
            }

            return ListHelper.ConvertToByteArray(this.PixelData);
        }
        set
        {
            if (value == null)
            {
                this.PixelData = null;
                return;
            }

            this.PixelData = ListHelper.ConvertToUshortArray(value);
        }
    }

}

Note that only the FileData property is marked as [DataMember], so that the PixelData property is not serialized!

Here are the relevant parts of the server’s app.config:

<system.serviceModel>
    <services>
        <service name="Services.ImageDataService" behaviorConfiguration="ServicesBehavior">
            <host>
                <baseAddresses>
                    <add baseAddress="net.tcp://localhost:8008/ImageDataService" />
                </baseAddresses>
            </host>
            <endpoint address="" binding="netTcpBinding" bindingConfiguration="NetTcpBindingLargeFileTransfer" contract="Services.IImageDataService" />
            <endpoint address="mex" binding="mexTcpBinding" bindingConfiguration="" contract="IMetadataExchange" />
        </service>
    </services>
    <behaviors>
        <serviceBehaviors>
            <behavior name="ServicesBehavior">
                <serviceMetadata httpGetEnabled="false" />
                <serviceDebug includeExceptionDetailInFaults="false" />
                <dataContractSerializer maxItemsInObjectGraph="2147483647"/>
            </behavior>
        </serviceBehaviors>
    </behaviors>
    <bindings>
        <netTcpBinding>
            <binding
                name="NetTcpBindingLargeFileTransfer"
                openTimeout="00:01:00" closeTimeout="00:01:00" receiveTimeout="infinite" sendTimeout="infinite"
                transactionFlow="false" transactionProtocol="OleTransactions"
                transferMode="Buffered" hostNameComparisonMode="StrongWildcard" listenBacklog="10"
                maxBufferPoolSize="2097152" maxBufferSize="1073741824" maxConnections="10" maxReceivedMessageSize="1073741824">
                <readerQuotas
                    maxDepth="2147483647" maxStringContentLength="2147483647"
                    maxArrayLength="2147483647" maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647" />
                <reliableSession ordered="true" inactivityTimeout="infinite" enabled="false" />
                <security mode="None">
                    <transport clientCredentialType="Windows" protectionLevel="EncryptAndSign" />
                    <message clientCredentialType="Windows" />
                </security>
            </binding>
        </netTcpBinding>
    </bindings>
</system.serviceModel>

And the client’s app.config:

<system.serviceModel>
    <bindings>
        <netTcpBinding>
            <binding
                name="NetTcpBindingLargeFileTransfer"
                openTimeout="00:01:00" closeTimeout="00:01:00" receiveTimeout="infinite" sendTimeout="00:10:00"
                transactionFlow="false" transactionProtocol="OleTransactions"
                transferMode="Buffered" hostNameComparisonMode="StrongWildcard" listenBacklog="10"
                maxBufferPoolSize="2097152" maxBufferSize="1073741824" maxConnections="10" maxReceivedMessageSize="1073741824">
                <readerQuotas
                    maxDepth="2147483647" maxStringContentLength="2147483647"
                    maxArrayLength="2147483647" maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647" />
                <reliableSession ordered="true" inactivityTimeout="infinite" enabled="false" />
                <security mode="None">
                    <transport clientCredentialType="Windows" protectionLevel="EncryptAndSign" />
                    <message clientCredentialType="Windows" />
                </security>
            </binding>
        </netTcpBinding>
    </bindings>
    <client>
        <endpoint
            address="net.tcp://localhost:8008/ImageDataService"
            binding="netTcpBinding"
            bindingConfiguration="NetTcpBindingLargeFileTransfer"
            contract="Services.IImageDataService"
            name="Services.IImageDataService"
            behaviorConfiguration="ServicesBehavior" />
    </client>
    <behaviors>
        <endpointBehaviors>
            <behavior name="ServicesBehavior">
                <dataContractSerializer maxItemsInObjectGraph="2147483647"></dataContractSerializer>
            </behavior>
        </endpointBehaviors>
    </behaviors>
</system.serviceModel>

Answer 1

On the same machine try named pipes.

Choosing a Transport