The following tips are related to AMD Performance.

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Note that this is NOT an AMD sizing document. AMD sizing practices depend on the amount and type of traffic to be analyzed and the detailed information you intend to extract from it. The purpose of this article is to provide instructions and guidelines on how to improve the AMD performance.

1. How much memory should be configured for the AMD software?

Before you make any changes, note that memory settings should be modified only in the following situations:

  • Processing of non-standard packets (jumbo frames)
  • Operating with both CBA and NFC services turned on  
  • Using non-standard traffic profile

 

Setting Data Memory Limit

The data memory limit is the maximum memory size that the AMD process is allowed to use (in megabytes); it is pre-configured to an optimum value at AMD software installation time but can be changed later if you add memory to the system.

To change one of the AMD memory limits:

  1. Run the rtminst command from the OS command line prompt.
  2. Select the AMD setup option from the main menu.
  3. Select the Data memory limit option from the AMD setup menu.
  4. Select the RTM data memory limit option from the Data memory limit menu.
  5. Select Edit property value from the menu and enter the new memory limit value.

When changing the RTM data memory limit, you should always use the recommended value, which is 70% of the system RAM size. As you may have noticed, the Data memory limit menu allows you to change the memory limits for v2page and page2trans processes as well. Please note that those values are set to optimal values by default. Changing them is an advanced operation and should not be performed unless it is explicitly recommended by Dynatrace.

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After applying the changes and exiting the rtminst menu, the AMD (all processes) will restart automatically in order to apply the changes.


Setting Packet Buffer Size

The packet buffer size is the size of the shared memory buffer that the AMD's RTM process uses for communication with the network driver and where the driver deposits data packets. This value is configurable only for 64-bit systems; it does not appear on the rtminst menu for 32-bit systems. Note that the size of this buffer is counted as a part of the data memory limit. You should always use the recommended (default) value and modify this setting only when new memory is added to the system. The recommended guideline is that the packet buffer size should be equal to 20% of the data memory limit, but not greater than 4 GB.

To change the packet buffer size:

  1. Run the rtminst command from the OS command line prompt.
  2. Select the AMD setup option from the main menu.
  3. Select the Packet buffer size setup option from the AMD setup menu.


Now, you can select a new value from the list or enter a custom value between 1 GB and 4 GB. The option to choose a custom value appears only if there is enough system memory and the upper limit of this range is never greater than 5 GB.

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After applying the changes and exiting the rtminst menu, the AMD (all processes) will restart automatically in order to apply the changes.

What to do next

If you experience further issues, contact Support for assistance.