Using ROCm SMI with C++

Using ROCm SMI with C++#

Installation#

Follow the installation procedure for rocm_smi_lib. Refer to the installation section.

Note

hipcc and other compilers will not automatically link in the librocm_smi64 dynamic library. To ensure the librocm_smi64.so can be located, you must either set the LD_LIBRARY_PATH environment variable to the directory containing librocm_smi64.so (usually /opt/rocm/lib) or pass the -lrocm_smi64 flag to the compiler.

Device indices#

Many of the functions in the library take a “device index”. The device index is a number greater than or equal to 0, and less than the number of devices detected, as determined by rsmi_num_monitor_devices(). The index is used to distinguish the detected devices from one another. It is important to note that a device may end up with a different index after a reboot, so an index should not be relied upon to be constant over reboots.

Hello ROCm SMI#

The only required ROCm-SMI call for any program that wants to use ROCm-SMI is the rsmi_init() call. This call initializes some internal data structures that will be used by subsequent ROCm-SMI calls.

When ROCm-SMI is no longer being used, rsmi_shut_down() should be called. This provides a way to do any releasing of resources that ROCm-SMI may have held. In many cases, this may have no effect, but may be necessary in future versions of the library.

A simple “Hello World” type program that displays the device ID of detected devices would look like this:

#include <stdint.h>
#include "rocm_smi/rocm_smi.h"
int main() {
  rsmi_status_t ret;
  uint32_t num_devices;
  uint16_t dev_id;

  // We will skip return code checks for this example, but it
  // is recommended to always check this as some calls may not
  // apply for some devices or ROCm releases

  ret = rsmi_init(0);
  ret = rsmi_num_monitor_devices(&num_devices);

  for (int i=0; i < num_devices; ++i) {
    ret = rsmi_dev_id_get(i, &dev_id);
    // dev_id holds the device ID of device i, upon a
    // successful call
  }
  ret = rsmi_shut_down();
  return 0;
}
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