rocm-systems/docs/how-to/using-amdsmi-for-C++.rst

.. meta::
  :description: Using AMD SMI 
  :keywords: AMD, SMI, system, management, interface, ROCm

********************************
Usage Basics for the C Library
********************************

Device/Socket handles
----------------------

Many of the AMD SMI library's functions take a "socket handle" or "device handle." The socket is an abstraction of the hardware's physical socket. This will enable AMD SMI to provide a better representation of the hardware to the user. Although there is always one distinct GPU for a socket, the APU may have both GPU and CPU devices on the same socket. Moreover, for the MI200 series, it may have multiple GCDs.

To discover the sockets in the system, `amdsmi_get_socket_handles()` is called to get a list of socket handles, which, in turn, can be used to query the devices in that socket using `amdsmi_get_processor_handles().` The device handler is used to distinguish the detected devices from one another. It is important to note that a device may end up with a different device handle after restarting the application, so a device handle should not be relied upon to be constant over the process.

The list of socket handles discovered using `amdsmi_get_socket_handles()`, can also be used to query the CPUs in that socket using amdsmi_get_processor_handles_by_type(), which in turn can then be used to query the cores in that CPU using amdsmi_get_processor_handles_by_type() again.


Hello AMD SMI
--------------

The only required AMD SMI call for any program that wants to use AMD SMI is the `amdsmi_init()` call. This call initializes some internal data structures that subsequent AMD-SMI calls will use. A flag can be passed in the call if the application is only interested in a specific device type.

When AMD SMI is no longer used, `amdsmi_shut_down()` should be called. This provides a way to release resources that AMD-SMI may have held.

1) A simple "Hello World" type program that displays the temperature of detected devices would look like this:

.. code-block:: 

            #include <iostream>
            #include <vector>
            #include "amd_smi/amdsmi.h"
                    
            int main() {
            amdsmi_status_t ret;
                
            // Init amdsmi for sockets and devices. Here we are only interested in AMD_GPUS.
               ret = amdsmi_init(AMDSMI_INIT_AMD_GPUS);
                    
            // Get all sockets
               uint32_t socket_count = 0;
                    
            // Get the socket count available in the system.
               ret = amdsmi_get_socket_handles(&socket_count, nullptr);
                    
            // Allocate the memory for the sockets
                std::vector<amdsmi_socket_handle> sockets(socket_count);
            // Get the socket handles in the system
               ret = amdsmi_get_socket_handles(&socket_count, &sockets[0]);
                    
              std::cout << "Total Socket: " << socket_count << std::endl;
                    
              // For each socket, get identifier and devices
                for (uint32_t i=0; i < socket_count; i++) {
              // Get Socket info
                 char socket_info[128];
                 ret = amdsmi_get_socket_info(sockets[i], 128, socket_info);
                std::cout << "Socket " << socket_info<< std::endl;
                    
              // Get the device count for the socket.
                 uint32_t device_count = 0;
                 ret = amdsmi_get_processor_handles(sockets[i], &device_count, nullptr);
                    
              // Allocate the memory for the device handlers on the socket
                 std::vector<amdsmi_processor_handle> processor_handles(device_count);
              // Get all devices of the socket
                 ret = amdsmi_get_processor_handles(sockets[i],
                  &device_count, &processor_handles[0]);
                    
              // For each device of the socket, get name and temperature.
                 for (uint32_t j=0; j < device_count; j++) {
              // Get device type. Since the amdsmi is initialized with
              // AMD_SMI_INIT_AMD_GPUS, the processor_type must be AMD_GPU.
                 processor_type_t processor_type;
                 ret = amdsmi_get_processor_type(processor_handles[j], &processor_type);
                 if (processor_type != AMD_GPU) {
                 std::cout << "Expect AMD_GPU device type!\n";
                  return 1;
                          }
                    
                // Get device name
                  amdsmi_board_info_t board_info;
                  ret = amdsmi_get_gpu_board_info(processor_handles[j], &board_info);
                  std::cout << "\tdevice "
                  << j <<"\n\t\tName:" << board_info.product_name << std::endl;
                    
              // Get temperature
                 int64_t val_i64 = 0;
                 ret =  amdsmi_get_temp_metric(processor_handles[j], AMDSMI_TEMPERATURE_TYPE_EDGE,
                  AMDSMI_TEMP_CURRENT, &val_i64);
                          std::cout << "\t\tTemperature: " << val_i64 << "C" << std::endl;
                        }
                      }
                    
            // Clean up resources allocated at amdsmi_init. It will invalidate sockets
            // and devices pointers
                  ret = amdsmi_shut_down();
                    
                      return 0;
                    }
              
            
2) A sample program that displays the power of detected cpus would look like this:
        
.. code-block:: 

            #include <iostream>
            #include <vector>
            #include "amd_smi/amdsmi.h"
                
            int main(int argc, char **argv) {
                amdsmi_status_t ret;
              uint32_t socket_count = 0;
                
             // Initialize amdsmi for AMD CPUs
                ret = amdsmi_init(AMDSMI_INIT_AMD_CPUS);
                
                ret = amdsmi_get_socket_handles(&socket_count, nullptr);
                
             // Allocate the memory for the sockets
                std::vector<amdsmi_socket_handle> sockets(socket_count);
            
            // Get the sockets of the system
               ret = amdsmi_get_socket_handles(&socket_count, &sockets[0]);
            
             std::cout << "Total Socket: " << socket_count << std::endl;
            
              // For each socket, get cpus
              for (uint32_t i = 0; i < socket_count; i++) {
                  uint32_t cpu_count = 0;
            
              // Set processor type as AMD_CPU
                 processor_type_t processor_type = AMD_CPU;
                  ret = amdsmi_get_processor_handles_by_type(sockets[i], processor_type, nullptr, &cpu_count);
            
              // Allocate the memory for the cpus
                  std::vector<amdsmi_processor_handle> plist(cpu_count);
            
            	// Get the cpus for each socket
                 ret = amdsmi_get_processor_handles_by_type(sockets[i], processor_type, &plist[0], &cpu_count);
            
                  for (uint32_t index = 0; index < plist.size(); index++) {
                    uint32_t socket_power;
                    std::cout<<"CPU "<<index<<"\t"<< std::endl;
                    std::cout<<"Power (Watts): ";
            
                      ret = amdsmi_get_cpu_socket_power(plist[index], &socket_power);
                      if(ret != AMDSMI_STATUS_SUCCESS)
                        std::cout<<"Failed to get cpu socket power"<<"["<<index<<"] , Err["<<ret<<"] "<< std::endl;
            
                    if (!ret) {
                      std::cout<<static_cast<double>(socket_power)/1000<<std::endl;
                        }
                        std::cout<<std::endl;
                    }
                }
            
              // Clean up resources allocated at amdsmi_init
              ret = amdsmi_shut_down();
            
              return 0;
            }
        

Building AMD SMI
-----------------

Rebuilding Python wrapper
==========================                                                             

Python wrapper (binding) is an auto-generated file `py-interface/amdsmi_wrapper.py`

The wrapper should be re-generated on each C++ API change by doing the following:


.. code-block:: bash
                                                               
    ./update_wrapper.sh


After this command, the file in `py-interface/amdsmi_wrapper.py` will be automatically updated on each compile.

Note: To re-generate the Python wrapper, you must have **Docker** installed.

Note: Python_wrapper is NOT automatically re-generated. You must run `./update_wrapper.sh`.


Additional software required for building AMD SMI
--------------------------------------------------                                                            

The following components are required to build the library.

.. Note:: The software versions listed are what was used in development. Earlier versions are not guaranteed to work.

* CMake (v3.14.0) - `python3 -m pip install cmake`
* g++ (5.4.0)

The following components are required to build the AMD SMI Python package:

* Clang (14.0 or above)
* Python (3.6.8 or above)
* virtualenv - `python3 -m pip install virtualenv`

The following tools are required to build the latest documentation:

* Doxygen (1.8.11)
* Latex (pdfTeX 3.14159265-2.6-1.40.16)

The source code for AMD SMI is available on Github.

After the AMD SMI library git repository is cloned to a local Linux machine, the default location for the library and headers is /opt/rocm. 

.. Note:: Before installation, the old ROCm directories must be deleted:

* /opt/rocm
* /opt/rocm-{number}

Building the library is achieved by following the typical CMake build sequence (run as root user or use 'sudo' before the 'make install' command), specifically:

.. code-block:: bash

      mkdir -p build
      cd build
      cmake ..
      make -j $(nproc)
      make install


The built library will appear in the `build` folder.

In addition to the preceding steps, use the following instructions to build the rpm and deb packages:

.. code-block:: bash

    make package

Building tests
-------------------

To verify the build and capability of AMD SMI on your system and see an example of how AMD SMI can be used, you may build and run the tests available in the repo. To build the tests, follow these steps:

.. code-block:: bash

      mkdir -p build
      cd build
      cmake -DBUILD_TESTS=ON ..
      make -j $(nproc)


Running tests
--------------

Execute the program `amdsmitst` that is built from the steps above to run the test. 

Path to the program `amdsmitst`: `build/tests/amd_smi_test/`