Graphics configuration and fine-tuning

This article provides guidance for the Linux VDA graphics configuration and fine-tuning.

For more information, see System requirements and the Installation overview section.

Configuration

Thinwire is the display remoting technology used in the Linux VDA. The technology allows graphics generated on one machine to be transmitted, typically across a network, to another machine for display.

The Use video codec for compression graphics policy sets the default graphics mode and provides the following options for different use cases:

• Use when preferred. This setting is the default. No additional configuration is required. It ensures that Thinwire is selected for all Citrix connections, and optimized for scalability, bandwidth, and superior image quality for typical desktop workloads.
• For the entire screen. Delivers Thinwire with full-screen H.264 or H.265 to optimize for improved user experience and bandwidth, especially in cases with heavy use of 3D graphics.
• For actively changing regions. The adaptive display technology in Thinwire identifies moving images (video, 3D in motion). It uses H.264 only in the part of the screen where the image is moving. The selective use of the H.264 video codec enables HDX Thinwire to detect and encode parts of the screen that are frequently updated using the H.264 video codec. Still image compression (JPEG, RLE) and bitmap caching continue to be used for the rest of the screen, including text and photographic imagery. Users get the benefit of lower bandwidth consumption and better quality for video content combined with lossless text or high quality imagery elsewhere. To enable this feature, change the policy setting Use video codec for compression to Use when preferred (default) or For actively changing regions. For more information, see Graphics policy settings.

Some other policy settings, including the following visual display policy settings can be used to fine-tune the performance of display remoting:

• Preferred color depth for simple graphics
• Target frame rate
• Visual quality

Parallel processing

Thinwire can improve the number of Frames Per Second (FPS) by parallelizing certain tasks, with the overhead of slightly higher overall CPU consumption. This feature is disabled by default. To enable the feature, run the following command on your VDA:

sudo /opt/Citrix/VDA/bin/ctxreg create -k "HKLM\System\CurrentControlSet\Control\Citrix\Thinwire" -t "REG_DWORD" -v "ParallelProcessing" -d "0x00000001" --force
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