AMD SMI C++ library usage and examples

AMD SMI C++ library usage and examples#

This section presents a brief overview and some basic examples on the AMD SMI library’s usage. Whether you are developing applications for performance monitoring, system diagnostics, or resource allocation, the AMD SMI C++ library serves as a valuable tool for leveraging the full potential of AMD hardware in your projects.

Note

hipcc and other compilers will not automatically link in the libamd_smi dynamic library. To compile code that uses the AMD SMI library API, ensure the libamd_smi.so can be located by setting the LD_LIBRARY_PATH environment variable to the directory containing librocm_smi64.so (usually /opt/rocm/lib) or by passing the -lamd_smi flag to the compiler.

Device and socket handles#

Many functions in the library take a socket handle or device handle. A socket refers to a physical hardware socket, abstracted by the library to represent the hardware more effectively to the user. While there is always one unique GPU per socket, an APU may house both a GPU and CPU on the same socket. For MI200 GPUs, multiple GCDs may reside within a single socket

To identify the sockets in a system, use the amdsmi_get_socket_handles() function, which returns a list of socket handles. These handles can then be used with amdsmi_get_processor_handles() to query devices within each socket. The device handle is used to differentiate between detected devices; however, it’s important to note that a device handle may change after restarting the application, so it should not be considered a persistent identifier across processes.

The list of socket handles obtained from amdsmi_get_socket_handles() can also be used to query the CPUs in each socket by calling amdsmi_get_processor_handles_by_type(). This function can then be called again to query the cores within each CPU.

Hello AMD SMI#

An application using AMD SMI must call amdsmi_init() to initialize the AMI SMI library before all other calls. This call initializes the internal data structures required for subsequent AMD SMI operations. In the call, a flag can be passed to indicate if the application is interested in a specific device type.

amdsmi_shut_down() must be the last call to properly close connection to driver and make sure that any resources held by AMD SMI are released.

A simple “Hello World” type program that displays the temperature of detected devices looks like this:

#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 AMDSMI_PROCESSOR_TYPE_AMD_GPU.
      processor_type_t processor_type;
      ret = amdsmi_get_processor_type(processor_handles[j], &processor_type);
      if (processor_type != AMDSMI_PROCESSOR_TYPE_AMD_GPU) {
        std::cout << "Expect AMDSMI_PROCESSOR_TYPE_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;
}

A sample program that displays the power of detected CPUs looks like this:

#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 AMDSMI_PROCESSOR_TYPE_AMD_CPU
        processor_type_t processor_type = AMDSMI_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;
}

AMD SMI C++ library usage and examples

Contents

AMD SMI C++ library usage and examples#

Device and socket handles#

Hello AMD SMI#