/* * Copyright © 2010-2020 Inria. All rights reserved. * See COPYING in top-level directory. */ /** \file * \brief Object distances. */ #ifndef HWLOC_DISTANCES_H #define HWLOC_DISTANCES_H #ifndef HWLOC_H #error Please include the main hwloc.h instead #endif #ifdef __cplusplus extern "C" { #elif 0 } #endif /** \defgroup hwlocality_distances_get Retrieve distances between objects * @{ */ /** \brief Matrix of distances between a set of objects. * * This matrix often contains latencies between NUMA nodes * (as reported in the System Locality Distance Information Table (SLIT) * in the ACPI specification), which may or may not be physically accurate. * It corresponds to the latency for accessing the memory of one node * from a core in another node. * The corresponding kind is ::HWLOC_DISTANCES_KIND_FROM_OS | ::HWLOC_DISTANCES_KIND_FROM_USER. * The name of this distances structure is "NUMALatency". * * The matrix may also contain bandwidths between random sets of objects, * possibly provided by the user, as specified in the \p kind attribute. */ struct hwloc_distances_s { unsigned nbobjs; /**< \brief Number of objects described by the distance matrix. */ hwloc_obj_t *objs; /**< \brief Array of objects described by the distance matrix. * These objects are not in any particular order, * see hwloc_distances_obj_index() and hwloc_distances_obj_pair_values() * for easy ways to find objects in this array and their corresponding values. */ unsigned long kind; /**< \brief OR'ed set of ::hwloc_distances_kind_e. */ hwloc_uint64_t *values; /**< \brief Matrix of distances between objects, stored as a one-dimension array. * * Distance from i-th to j-th object is stored in slot i*nbobjs+j. * The meaning of the value depends on the \p kind attribute. */ }; /** \brief Kinds of distance matrices. * * The \p kind attribute of struct hwloc_distances_s is a OR'ed set * of kinds. * * A kind of format HWLOC_DISTANCES_KIND_FROM_* specifies where the * distance information comes from, if known. * * A kind of format HWLOC_DISTANCES_KIND_MEANS_* specifies whether * values are latencies or bandwidths, if applicable. */ enum hwloc_distances_kind_e { /** \brief These distances were obtained from the operating system or hardware. * \hideinitializer */ HWLOC_DISTANCES_KIND_FROM_OS = (1UL<<0), /** \brief These distances were provided by the user. * \hideinitializer */ HWLOC_DISTANCES_KIND_FROM_USER = (1UL<<1), /** \brief Distance values are similar to latencies between objects. * Values are smaller for closer objects, hence minimal on the diagonal * of the matrix (distance between an object and itself). * It could also be the number of network hops between objects, etc. * \hideinitializer */ HWLOC_DISTANCES_KIND_MEANS_LATENCY = (1UL<<2), /** \brief Distance values are similar to bandwidths between objects. * Values are higher for closer objects, hence maximal on the diagonal * of the matrix (distance between an object and itself). * Such values are currently ignored for distance-based grouping. * \hideinitializer */ HWLOC_DISTANCES_KIND_MEANS_BANDWIDTH = (1UL<<3), /** \brief This distances structure covers objects of different types. * \hideinitializer */ HWLOC_DISTANCES_KIND_HETEROGENEOUS_TYPES = (1UL<<4) }; /** \brief Retrieve distance matrices. * * Retrieve distance matrices from the topology into the \p distances array. * * \p flags is currently unused, should be \c 0. * * \p kind serves as a filter. If \c 0, all distance matrices are returned. * If it contains some HWLOC_DISTANCES_KIND_FROM_*, only distance matrices * whose kind matches one of these are returned. * If it contains some HWLOC_DISTANCES_KIND_MEANS_*, only distance matrices * whose kind matches one of these are returned. * * On input, \p nr points to the number of distance matrices that may be stored * in \p distances. * On output, \p nr points to the number of distance matrices that were actually * found, even if some of them couldn't be stored in \p distances. * Distance matrices that couldn't be stored are ignored, but the function still * returns success (\c 0). The caller may find out by comparing the value pointed * by \p nr before and after the function call. * * Each distance matrix returned in the \p distances array should be released * by the caller using hwloc_distances_release(). */ HWLOC_DECLSPEC int hwloc_distances_get(hwloc_topology_t topology, unsigned *nr, struct hwloc_distances_s **distances, unsigned long kind, unsigned long flags); /** \brief Retrieve distance matrices for object at a specific depth in the topology. * * Identical to hwloc_distances_get() with the additional \p depth filter. */ HWLOC_DECLSPEC int hwloc_distances_get_by_depth(hwloc_topology_t topology, int depth, unsigned *nr, struct hwloc_distances_s **distances, unsigned long kind, unsigned long flags); /** \brief Retrieve distance matrices for object of a specific type. * * Identical to hwloc_distances_get() with the additional \p type filter. */ HWLOC_DECLSPEC int hwloc_distances_get_by_type(hwloc_topology_t topology, hwloc_obj_type_t type, unsigned *nr, struct hwloc_distances_s **distances, unsigned long kind, unsigned long flags); /** \brief Retrieve a distance matrix with the given name. * * Usually only one distances structure may match a given name. * * The name of the most common structure is "NUMALatency". */ HWLOC_DECLSPEC int hwloc_distances_get_by_name(hwloc_topology_t topology, const char *name, unsigned *nr, struct hwloc_distances_s **distances, unsigned long flags); /** \brief Get a description of what a distances structure contains. * * For instance "NUMALatency" for hardware-provided NUMA distances (ACPI SLIT), * or NULL if unknown. */ HWLOC_DECLSPEC const char * hwloc_distances_get_name(hwloc_topology_t topology, struct hwloc_distances_s *distances); /** \brief Release a distance matrix structure previously returned by hwloc_distances_get(). * * \note This function is not required if the structure is removed with hwloc_distances_release_remove(). */ HWLOC_DECLSPEC void hwloc_distances_release(hwloc_topology_t topology, struct hwloc_distances_s *distances); /** @} */ /** \defgroup hwlocality_distances_consult Helpers for consulting distance matrices * @{ */ /** \brief Find the index of an object in a distances structure. * * \return -1 if object \p obj is not involved in structure \p distances. */ static __hwloc_inline int hwloc_distances_obj_index(struct hwloc_distances_s *distances, hwloc_obj_t obj) { unsigned i; for(i=0; inbobjs; i++) if (distances->objs[i] == obj) return (int)i; return -1; } /** \brief Find the values between two objects in a distance matrices. * * The distance from \p obj1 to \p obj2 is stored in the value pointed by * \p value1to2 and reciprocally. * * \return -1 if object \p obj1 or \p obj2 is not involved in structure \p distances. */ static __hwloc_inline int hwloc_distances_obj_pair_values(struct hwloc_distances_s *distances, hwloc_obj_t obj1, hwloc_obj_t obj2, hwloc_uint64_t *value1to2, hwloc_uint64_t *value2to1) { int i1 = hwloc_distances_obj_index(distances, obj1); int i2 = hwloc_distances_obj_index(distances, obj2); if (i1 < 0 || i2 < 0) return -1; *value1to2 = distances->values[i1 * distances->nbobjs + i2]; *value2to1 = distances->values[i2 * distances->nbobjs + i1]; return 0; } /** @} */ /** \defgroup hwlocality_distances_add Add or remove distances between objects * @{ */ /** \brief Flags for adding a new distances to a topology. */ enum hwloc_distances_add_flag_e { /** \brief Try to group objects based on the newly provided distance information. * \hideinitializer */ HWLOC_DISTANCES_ADD_FLAG_GROUP = (1UL<<0), /** \brief If grouping, consider the distance values as inaccurate and relax the * comparisons during the grouping algorithms. The actual accuracy may be modified * through the HWLOC_GROUPING_ACCURACY environment variable (see \ref envvar). * \hideinitializer */ HWLOC_DISTANCES_ADD_FLAG_GROUP_INACCURATE = (1UL<<1) }; /** \brief Provide a new distance matrix. * * Provide the matrix of distances between a set of objects given by \p nbobjs * and the \p objs array. \p nbobjs must be at least 2. * The distances are stored as a one-dimension array in \p values. * The distance from object i to object j is in slot i*nbobjs+j. * * \p kind specifies the kind of distance as a OR'ed set of ::hwloc_distances_kind_e. * Kind ::HWLOC_DISTANCES_KIND_HETEROGENEOUS_TYPES will be automatically added * if objects of different types are given. * * \p flags configures the behavior of the function using an optional OR'ed set of * ::hwloc_distances_add_flag_e. */ HWLOC_DECLSPEC int hwloc_distances_add(hwloc_topology_t topology, unsigned nbobjs, hwloc_obj_t *objs, hwloc_uint64_t *values, unsigned long kind, unsigned long flags); /** \brief Remove all distance matrices from a topology. * * Remove all distance matrices, either provided by the user or * gathered through the OS. * * If these distances were used to group objects, these additional * Group objects are not removed from the topology. */ HWLOC_DECLSPEC int hwloc_distances_remove(hwloc_topology_t topology); /** \brief Remove distance matrices for objects at a specific depth in the topology. * * Identical to hwloc_distances_remove() but only applies to one level of the topology. */ HWLOC_DECLSPEC int hwloc_distances_remove_by_depth(hwloc_topology_t topology, int depth); /** \brief Remove distance matrices for objects of a specific type in the topology. * * Identical to hwloc_distances_remove() but only applies to one level of the topology. */ static __hwloc_inline int hwloc_distances_remove_by_type(hwloc_topology_t topology, hwloc_obj_type_t type) { int depth = hwloc_get_type_depth(topology, type); if (depth == HWLOC_TYPE_DEPTH_UNKNOWN || depth == HWLOC_TYPE_DEPTH_MULTIPLE) return 0; return hwloc_distances_remove_by_depth(topology, depth); } /** \brief Release and remove the given distance matrice from the topology. * * This function includes a call to hwloc_distances_release(). */ HWLOC_DECLSPEC int hwloc_distances_release_remove(hwloc_topology_t topology, struct hwloc_distances_s *distances); /** @} */ #ifdef __cplusplus } /* extern "C" */ #endif #endif /* HWLOC_DISTANCES_H */