.. _multi-gpu-debugging:

*Tutorial: Debugging with Intel® Distribution for GDB\**


Multi-GPU Debugging
===================


The debugger supports debugging a program that offloads kernels to
multiple GPU devices. Each device appears in the debugger as a separate
inferior. The auto-attach feature initializes the devices for debugging
and creates the corresponding inferiors. For example, for a program that
runs on a machine with two GPUs (one integrated, one discrete), when you
execute the ``run`` command from the ``(gdb)`` prompt:


.. code-block::


    run


A possible output is as follows:


.. code-block::


   Starting program: ./multi-device-program  
   [Thread debugging using libthread_db enabled] 
   Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". 
   [New Thread
   0x7ffff4871700 (LWP 394698)]  
   intelgt: gdbserver-gt started for process 394694.
   [...]  
   intelgt: attached to device 1 of 2; id 0x3e92 (Gen9) on inferior 2.
   [...] 
   intelgt: attached to device 2 of 2; id 0x9a40 (Gen12) on inferior 3.


.. note::


   Switching between the inferiors and threads is the same as explained
   in the :ref:`Basic Debugging <basic_debugging_gpu>` section.