geopm_topo(3) – query platform component topology

Synopsis

Link with -lgeopm (MPI) or -lgeopm (non-MPI)

int geopm_topo_num_domain(int domain_type);

int geopm_topo_domain_idx(int domain_type,
                          int cpu_idx);

int geopm_topo_num_domain_nested(int inner_domain,
                                 int outer_domain);

int geopm_topo_domain_nested(int inner_domain,
                             int outer_domain,
                             int outer_idx,
                             size_t num_domain_nested,
                             int *domain_nested);


int geopm_topo_domain_name(int domain_type,
                           size_t domain_name_max,
                           char *domain_name);

int geopm_topo_domain_type(const char *domain_name);

int geopm_topo_create_cache(void);

Domain Types

The geopm_domain_e enum defines a set of values that correspond to hardware components on the system:

GEOPM_DOMAIN_INVALID = -1: Indicates an invalid domain.
GEOPM_DOMAIN_BOARD = 0: All components on a user allocated compute node. There is only a single board per compute node, and every other domain is contained with the board domain.
GEOPM_DOMAIN_PACKAGE = 1: A collection of all the hardware present on a single processor package installed on a distinct socket of a motherboard.
GEOPM_DOMAIN_CORE = 2: Physical core, i.e. a group of associated hyper-threads
GEOPM_DOMAIN_CPU = 3: Linux logical CPU. In practice, there is one logical CPU per hyperthread visible to the operating system.
GEOPM_DOMAIN_MEMORY = 4: Standard off-package DIMM (DRAM or NAND).
GEOPM_DOMAIN_PACKAGE_INTEGRATED_MEMORY = 5: On-package memory (MCDRAM).
GEOPM_DOMAIN_NIC = 6: Peripheral network interface controller not on the processor package.
GEOPM_DOMAIN_PACKAGE_INTEGRATED_NIC = 7: Network interface controller on the processor package.
GEOPM_DOMAIN_GPU = 8: Peripheral GPU card not on the processor package.
GEOPM_DOMAIN_PACKAGE_INTEGRATED_GPU = 9: GPU unit on the package (e.g on-package graphics).
GEOPM_DOMAIN_GPU_CHIP = 10: GPU card chips within a package on the PCI Bus (e.g Level Zero subdevices).
GEOPM_NUM_DOMAIN = 11: The number of valid built-in domains.

Description

The interfaces described in this man page are the C language bindings for the geopm::PlatformTopo(3) C++ class. Please refer to the geopm::PlatformTopo(3) man page for a general description of the purpose, goals and use case for this interface.

geopm_topo_num_domain(): Returns the number of domains available on the system of type domain_type. If the domain_type is valid, but there are no domains of that type on the system, the return value is zero. If the domain is not a valid domain defined by the geopm_domain_e enum then the function will return a negative error code: GEOPM_ERROR_INVALID.
geopm_topo_domain_idx(): Returns the index of the domain of type domain_type that is local to the Linux logical CPU cpu_idx. The return value will be greater than or equal to zero and less than the value returned by geopm_topo_num_domain() for valid input parameters. If domain_type or cpu_idx are out of range a negative error code is returned: GEOPM_ERROR_INVALID.
geopm_topo_num_domain_nested(): Returns the number of domains of type inner_domain that are contained within each domain of outer_domain type. The return value is one if inner_domain is equal to outer_domain. If inner_domain is not contained within outer_domain a negative error code is returned: GEOPM_ERROR_INVALID. Any non-negative return value can be used to size the domain_nested array that is passed to geopm_topo_domain_nested() with the same values for inner_domain and outer_domain.
geopm_topo_domain_nested(): Fills the output array domain_nested with the domain indices of all of the inner_domain types nested within the specific outer_domain type indexed by outer_idx. num_domain_nested defines the length of the domain_nested array and must match the positive return value from geopm_topo_num_domain_nested(). Zero is returned upon success. A negative error code is returned if inner_domain is not within outer_domain, or if outer_idx is not between zero and geopm_topo_num_domain().
geopm_topo_domain_name(): Sets the domain_name string to the name associated with the domain_type selected from the geopm_domain_e enum. At most result_max bytes are written to the domain_name string. Providing a string of NAME_MAX length (from limits.h) will be sufficient for storing any result. If result_max is too small to contain the domain name an error will occur. Zero is returned on success and a negative error code is returned if any error occurs.
geopm_topo_domain_type(): Returns the domain type that is associated with the provided domain_name string. This is the inverse function to geopm_topo_domain_name() and the input domain_name must match the output from geopm_topo_domain_name() for a valid domain type. If the string does not match any of the valid domain names, then GEOPM_DOMAIN_INVALID is returned.
geopm_topo_create_cache():: Create a cache file for the geopm::PlatformTopo(3) object if one does not exist. This cache file will be used by any calls to the other geopm_topo_*() functions documented here as well as any use of the GEOPM runtime. If a privileged user is making this call (i.e. root or via sudo), the file path will be /run/geopm/geopm-topo-cache. If a non-privileged user makes this call file path will be /tmp/geopm-topo-cache-<UID>. In either case, the permissions will be -rw-------, i.e. 600. If the file exists from the current boot cycle and has the proper permissions no operation will be performed. To force the creation of a new cache file, unlink(3) the existing cache file prior to calling this function.

Return Value

If an error occurs in any call to an interface documented here, the return value of the function will be a negative integer corresponding to one of the error codes documented in geopm_error(3).

geopm_topo(3) – query platform component topology

Synopsis

Domain Types

Description

Return Value

See Also