## memory_object_perf_info

Structure - Specifies a memory object's attributes with respect to performance.

### SYNOPSIS

    struct  memory_object_perf_info
    {
            vm_offset_t      cluster_size;
            boolean_t    may_cache_object;
    };

    typedef struct memory_object_perf_info* memory_object_perf_info_t;

### FIELDS

cluster_size
  Preferred cluster size (in bytes) for the memory object. This helps to determine how many pages are transferred in individual data request and return messages.

may_cache_object
  Cache indicator. If true, the kernel can cache data associated with the memory object (keep the memory object active) even if no virtual memory references to it remain.

### DESCRIPTION

The memory_object_perf_info structure defines a memory object's character with respect to performance.

### NOTES

Sharing cached data among all the clients of a memory object can have a major impact on performance, especially if it can be extended across successive, as well as concurrent, uses. For example, the memory objects that represent program images can be used regularly by different programs. By retaining the data for these memory objects in cache, the number of secondary storage accesses can be reduced significantly.

### RELATED INFORMATION

Functions: memory_object_get_attributes, memory_object_change_attributes, vm_region, memory_object_synchronize, vm_set_default_memory_manager, vm_msync.

Structures: memory_object_attr_info.