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Optimizing Reflective Memory

Last Modified: June 10, 2021

Improve the use of your reflective memory usage by reducing the dynamic data size, creating channel mappings between targets, and using data channels selectively with non-VeriStand systems.

Before you begin, add a reflective memory network.
  1. Launch the VeriStand Editor.
  2. In the Project Files pane, double-click a system definition file (.nivssdf). System Explorer opens.
  3. To optimize your reflective memory performance, complete any of the following tasks.
    Goal Tasks Rationale
    Reduce the dynamic data size of the data sharing network to 0.
    1. Click Data Sharing Network.
    2. On the Data Sharing Network configuration page, enter the Dynamic Data Size as 0.
    Dynamic Data Size specifies the number of channels in reflective memory to reserve for dynamically mapping channel data at run time. Reflective memory can negatively impact performance. Reducing the number of channels to 0 avoids decreasing performance.
    spd-note-note
    Note  

    This is only recommended for systems that do not execute stimulus profiles or perform data logging that references channels across multiple targets.

    Create channel mappings between targets in the system definition file.
    1. Create channel mappings between targets.
    2. Prevent reflective memory used by VeriStand from overlapping with any non-VeriStand traffic on the bus.
      1. Click Configure Mappings .
      2. In the System Configuration Mappings dialog box, click the Network drop-down and select Reflective Memory Network .
      3. Click OK.
      4. Click Data Sharing Network»Reflective Memory Network.
      5. On the Reflective Memory Network Configuration page, enter a Start Memory Address and Maximum End Address Block to limit the range of addresses the systems can use.

    Rather than using data channels to read and write data between targets in a system definition, create channel mappings between targets. When you configure channel mappings, VeriStand uses optimized reflective memory.

    When sending data from a VeriStand system to a non-VeriStand system, manually select channels to add to reflective memory and read those channels from the non-VeriStand system.
    1. Click Controller»Hardware»Chassis»Data Sharing»Reflective Memory.
    2. Click Export Channels.
    3. In the Export Channels to Reflective Memory dialog box, select channels to export and click OK.
    4. Click Data Sharing Network»Reflective Memory Network.
    5. On the Reflective Memory Network Configuration page, click Export memory table to file.

    VeriStand adds the channels you export to the direct memory access (DMA) block write for the target. This reduces CPU usage.

    After selecting the channels to export, you must configure the non-VeriStand systems to read the memory addresses of the exported channels. The Export memory table to file option creates a text file that contains the memory addresses when you deploy the system definition file.

    When a VeriStand system must read data from a non-VeriStand system, add data channels to only the targets that require the data.
    • Click Controller»Hardware»Chassis»Data Sharing»Reflective Memory.
    • Click Add Data Channel.

    Data channels allow you to specify the reflective memory addresses a VeriStand target reads. However, you should only add data channels you intend to use. VeriStand reads the memory addresses one at a time. The more addresses VeriStand reads, the slower the performance.

  4. Save the system definition file.

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