dmi_cache

Synopsis

#include <opendmi/entity/cache.h>

typedef struct dmi_cache {
    const char *socket_designator;
    unsigned short level;
    bool socketed;
    dmi_cache_location_t location;
    bool enabled;
    dmi_cache_mode_t mode;
    dmi_size_t maximum_size;
    dmi_size_t installed_size;
    dmi_cache_sram_type_t supported_sram;
    dmi_cache_sram_type_t current_sram;
    unsigned int speed;
    dmi_error_correct_type_t error_correction;
    dmi_cache_type_t type;
    dmi_cache_assoc_t associativity;
} dmi_cache_t;

Description

The dmi_cache_t structure holds the decoded cache information structure (type 7) of SMBIOS: the level, location, operational mode, sizes, SRAM types, speed and associativity of one processor cache. A table carries one such structure for each cache, whether the cache is internal or external to the processor module. Processor information structures (type 4) refer to the caches of their processor by handle.

The structure is returned by dmi_entity_info for the structures of type DMI_TYPE(cache), and lives as long as the context it has been decoded in.

Fields

socket_designator: Reference designation of the cache socket, for example "CACHE1", or nullptr if the structure has none.
level: Cache level, 1 to 8 (1 for an L1 cache). The data counts the levels from zero, and the decoder adds one.
socketed: true if the cache sits in a socket (for example, cache on a stick), false otherwise.
location: Location of the cache, relative to the processor module, see dmi_cache_location.
enabled: true if the cache is enabled at boot time.
mode: Operational mode of the cache, see dmi_cache_mode.
maximum_size: Largest size of cache the socket can take, in bytes. The data carries it in granules of 1 KiB or 64 KiB. Since SMBIOS 3.1, a cache of 2 GiB or more sets the 16-bit field to 0xFFFF and carries its size in a 32-bit extended field, which the decoder then uses.
installed_size: Size of the installed cache, in bytes, or 0 if no cache is installed. Carried the same way as maximum_size.
supported_sram: Set of the SRAM types the cache supports, see dmi_cache_sram_type.
current_sram: Set of the SRAM types the cache currently uses, see dmi_cache_sram_type.
speed: Speed of the cache module, in nanoseconds, or 0 if unknown. Present since SMBIOS 2.1; 0 in older structures.
error_correction: Error-correction scheme the cache supports, see dmi_error_correct_type. Present since SMBIOS 2.1; DMI_ERROR_CORRECT_TYPE_UNSPEC in older structures.
type: Logical type of the cache: instruction, data or unified, see dmi_cache_type. Present since SMBIOS 2.1; DMI_CACHE_TYPE_UNSPEC in older structures.
associativity: Associativity of the cache, see dmi_cache_assoc. Present since SMBIOS 2.1; DMI_CACHE_ASSOC_UNSPEC in older structures.

Examples

dmi_registry_t *registry = dmi_get_registry(context);
dmi_entity_t   *entity   = dmi_registry_lookup_first(registry,
                                                     DMI_TYPE(cache), false);
dmi_cache_t    *cache    = dmi_entity_info(entity, DMI_TYPE(cache));

if (cache != nullptr)
    printf("L%u cache: %s, %llu KiB\n", cache->level,
           dmi_cache_type_name(cache->type),
           (unsigned long long)(cache->installed_size >> 10));

Standards

DMTF SMBIOS Specification (DSP0134), version 2.0 or newer.