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AI Engine Debug Walkthrough Tutorial - From Simulation to Hardware

AI Engine/PL Kernel Debug with XRT Utilities on HW

This section is useful when running the design in HW, and there is a stall/hang. First step is to examine the errors from XRT which in turn reflects the errors from the AIE driver. The steps below show you how to obtain this information running the tutorial design in HW.

xbutil

The utility, xbutil, is supported for PL/AI Engine debug. It can be used to

Report AI Engine Status

Step 0 Prepare the boot image and boot the board

After the design is built correctly without error, we are ready to run on the hardware board.

  • Flash the SD card with the built sd_card.img.
  • Plug the flashed SD card into the SD card slot of the vck190 board.
  • Connect the USB type C cable to the board and computer that supports serial port connection.
  • Set the serial port configuration with Speed=115200, Data=8 bit, Parity=none, Stop bits=1 bit and flow control=none.
  • Power up the vck190 board to see boot messages from serial connection.

Step 1.1 Generate AI Engine status data

Create an xrt.ini file on SD card using the following lines.

[Debug]
aie_status=true
aie_status_interval_us=1000

Step 1.2 to Run Application after Petalinux Boots up on Board

cd /run/media/mmcblk0p1
./host.exe a.xclbin

Step 1.3 Collect AI Engine Status Files

After the design run completes on the hardware, the generated profiling files and run_summary files need to be collected and ready to be examined.

Step 1.3.1

Make sure aie_status_edge.json, aieshim_status_edge.json, summary.csv and xrt.run_summary files are generated on the SD card.

Step 1.3.2

Power off the board and take out the SD card from the board, and plug it into the host SD card reader.

Step 1.3.3

Copy aie_status_edge.json, aieshim_status_edge.json, summary.csv and xrt.run_summary files from the SD card back to where the design is.

  • xrt.run_summary: Run summary that contains list of files information that can be used by vitis analyzer.
  • aie_status_edge.json: Status of AI Engine and AI Engine memory.
  • aieshim_status_edge.json: AI Engine interface tiles status.
  • summary.csv: Always created.

Step 1.4 Launch Vitis Analyzer to Examine Status Files

vitis_analyzer xrt.run_summary

After above command issued, expect to see vitis_analyzer GUI is launched. Click on Set AI Engine compile summary in the summary view to set the AI Engine compile summary ![alt text](images/bc_va.png">

AI Engine Status Explanation

Click on Graph view then Tile Status.

  • Tile Status: Shows all tiles completed execution and at Disabled, Done state. ![alt text](images/bc_va1.png">

  • PC: Shows the current PC (program counter) value. It can be cross-probed with source code by clicking it. ![alt text](images/bc_va3.png">

  • Error Event: Shows error events that occurred before the status was generated.

  • Buffers: Shows buffer objects in the design with the current status.

Click on DMA Status. DMA status shows each tile's DMA input/output channel status. ![alt text](images/bc_va2.png">

Reference UG1076, Analyzing AI Engine Status in Vitis Analyzer section for details.

Report XRT Errors

Reference xrt-error-api for detail information.

Report Mechanism with XRT APIs

Asynchronous errors are cached in driver subsystems and can be accessed by user application through APIs. Asynchronous errors retrieved from the driver are shared between user space and kernel space.

Example using XRT APIs:

    dut.run(100);
    try {
        dut.wait();
    }
    catch (const std::system_error& ex) {
        if (ex.code().value() == ETIME) {
            xrt::error error(device, XRT_ERROR_CLASS_AIE);

            auto errCode = error.get_error_code();
            auto timestamp = error.get_timestamp();
            auto err_str = error.to_string();

            /* code to deal with this specific error */
            std::cout << timestamp << " error code:" << errCode << " Error:" << err_str << std::endl;
         } else {
         /* Something else */
         }
     }

Step 2.1 Replace host.cpp with host.cpp.error_code that is available from this tutorial.

cp ${PROJECT_PATH}/sw/host.cpp.error_code ${PROJECT_PATH}/sw/host.cpp
cd ${PROJECT_PATH}

Step 2.2 Compile the host.cpp code and package to sd_card.img by issuing the following commands.

make host.exe
make package

Step 2.3 Follow step 0 Prepare the boot image and boot the board

Step 0 Prepare the boot image and boot the board

Step 2.4 After VCK190 is powered up and booted up complete, run the binaries.

cd /run/media/mmcblk0p1
./host.exe a.xclbin

Step 2.5 Expected result is as follows.

alt text

Step 2.6 Report Mechanism with xbutil

Issue command xbutil examine -d 0000:00:00.0 -r error to VCK190 console to get output from console. alt text

Support

GitHub issues will be used for tracking requests and bugs. For questions go to support.xilinx.com.

License

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

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