Xilinx Runtime Library GDB Extensions - 2021.2 English

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

Document ID
UG1393
ft:locale
English (United States)
Release Date
2021-12-15
Version
2021.2 English
The Vitis debugger (xgdb) enables new GDB commands that give you visibility from the host application into the XRT library.
Note: If you launch GDB outside of the Vitis debugger, the command extensions need to be enabled using the appdebug.py script as described in Launching Host and Kernel Debug.

There are two kinds of commands which can be called from the gdb command line:

  1. xprint commands that give visibility into XRT library data structures (cl_command_queue, cl_event, and cl_mem). These commands are explained below.
  2. xstatus commands that give visibility into IP running on the Vitis target platform when debugging during hardware execution.

You can get more information about the xprint and xstatus commands by using the help <command> from the gdb command prompt.

A typical application for these commands is when you see the host application hang. In this case, the host application could be waiting for the command queue to finish, or waiting on an event list. Printing the command queue using the xprint queue command can tell you what events are unfinished, allowing you to analyze dependencies between events.

The output of both of these commands is automatically tracked when debugging with the Vitis IDE. In this case, three tabs are provided next to the common tabs for Variables, Breakpoints, and Registers in the upper left corner of the debug perspective. These are labeled Command Queue, Memory Buffers, and Platform Debug, showing the output of xprint queue, xprint mem, and xstatus, respectively.