Buffer Allocation on the Device - 2021.2 English

Vitis Unified Software Platform Documentation: Application Acceleration Development (UG1393)

Document ID
English (United States)
Release Date
2021.2 English

By default, when kernels are linked to the platform the memory interfaces from all the kernels are connected to a single default global memory bank. As a result, only a single compute unit (CU) can transfer data to and from the global memory bank at one time, limiting the overall performance of the application.

If the device contains only one global memory bank, then this is the only option. However, if the device contains multiple global memory banks, you can customize the global memory bank connections by modifying the memory interface connection for a kernel during linking. The method for performing this is discussed in detail in Mapping Kernel Ports to Memory. Overall performance is improved by using separate memory banks for different kernels or compute units, enabling multiple kernel memory interfaces to concurrently read and write data.

Important: XRT must detect the kernel's memory connection to send data from the host program to the correct memory location for the kernel. XRT will automatically find the buffer location from the kernel binary files if clSetKernelArgs is used before any enqueue operation on the buffer, such as clEnqueueMigrateMemObject.