Object attributes

# Normal attributes

hwloc objects have many attributes. The hwloc_obj structure contains a common set of attributes that are available for object types, for instance their `type` or `logical_index`.

Each object also contains an `attr` field that, if non NULL, points to a union hwloc_obj_attr_u of type-specific attribute structures. For instance, a Cache object `obj` contains cache-specific information in `obj->attr->cache`, such as its size and associativity. See hwloc_obj_attr_u for details.

# Custom string infos

Aside from the `name` field of each object, hwloc annotates many objects with string attributes that are made of a key and a value. Each object contains a list of such pairs that may be consulted manually (looking at the object `infos` array field) or using the hwloc_obj_get_info_by_name(). The user may additionally add new key-value pairs to any object using hwloc_obj_add_info() or the hwloc-annotate program.

Here is a non-exhaustive list of attributes that may be automatically added by hwloc (with the usual corresponding object in parentheses). Note that these attributes heavily depend on the ability of the operating system to report them. Many of them will therefore be missing on some OS.

OSName, OSRelease, OSVersion, HostName, Architecture (Machine object)
  The operating system name, release, version, the hostname and the architecture name, as reported by the Unix `uname` command.
Backend (Machine object or topology root object)
  The name of the hwloc backend/component that filled the topology. If several components were combined, multiple Backend keys may exist, with different values, for instance `x86`, `Linux` and `pci`.
LinuxCgroup (Machine object)
  The name the Linux control group where the calling process is placed.
SyntheticDescription (topology root object)
  The description string that was given to hwloc to build this synthetic topology.
CPUModel (Package or Machine)
  The processor model name. Usually added to Package objects, but can be in Machine instead if hwloc failed to discover any package.
CPUType (Package)
  A Solaris-specific general processor type name, such as "i86pc".
CPUVendor, CPUModelNumber, CPUFamilyNumber, CPUStepping (Package or Machine)
  The processor vendor name, model number, family number, and stepping number. Currently available for x86 and Xeon Phi processors on most systems, and for ia64 processors on Linux (except CPUStepping). Usually added to Package objects, but can be in Machine instead if hwloc failed to discover any package.
CPURevision (Package)
  A POWER/PowerPC-specific general processor revision number, currently only available on Linux.
PlatformName, PlatformModel, PlatformVendor, PlatformBoardID, PlatformRevision,
SystemVersionRegister, ProcessorVersionRegister (Machine)
  Some POWER/PowerPC-specific attributes describing the platform and processor. Currently only available on Linux. Usually added to Package objects, but can be in Machine instead if hwloc failed to discover any package.
PCIVendor, PCIDevice (PCI devices and bridges)
  The vendor and device names of the PCI device.
PCISlot
  The name/number of the physical slot where the PCI device is plugged.
Vendor, Model, Revision, SerialNumber
  The vendor and model names, and revision and serial numbers of a Block OS device.
LinuxDeviceID
  The major/minor device number such as 8:0 on Linux for a Block OS device.
CoProcType (Co-Processor OS devices)
  The type of co-processor, for instance `"MIC"`, `"CUDA"` or `"OpenCL"`.
GPUVendor, GPUModel (GPU or Co-Processor OS devices)
  The vendor and model names of the GPU device.
OpenCLDeviceType, OpenCLPlatformIndex,
OpenCLPlatformName, OpenCLPlatformDeviceIndex (OpenCL GPU OS devices)
  The type of OpenCL device, the OpenCL platform index and name, and the index of the device within the platform.
OpenCLComputeUnits, OpenCLGlobalMemorySize
  The number of compute units and global memory size (in kB) of a OpenCL device.
NVIDIAUUID, NVIDIASerial (NVML GPU OS devices)
  The UUID and Serial of NVIDIA GPUs.
CUDAMultiProcessors, CUDACoresPerMP,
CUDAGlobalMemorySize, CUDAL2CacheSize, CUDASharedMemorySizePerMP (CUDA OS devices)
  The number of shared multiprocessors, the number of cores per multiprocessor, the global memory size, the (global) L2 cache size, and size of the shared memory in each multiprocessor of a CUDA device. Sizes are in kB.
MICSerialNumber
  The serial number of an Intel Xeon Phi (MIC) coprocessor. hwloc may run either inside the coprocessor itself, or on the host processor. That attribute is set in both cases, so that the exact same coprocessor may be identified from both point of views, even if there are multiple nodes with multiple MICs. When running hwloc on the host, each hwloc OS device object that corresponds to a Xeon Phi gets such an attribute. When running hwloc inside a Xeon Phi coprocessor, the root object of the topology gets this attribute.
MICFamily, MICSKU, MICActiveCores, MICMemorySize
  The family, SKU (model), number of active cores, and memory size (in kB) of an Intel Xeon Phi (MIC) coprocessor.
DMIBoardVendor, DMIBoardName, etc. (Machine object)
  DMI hardware information such as the motherboard and chassis models and vendors, the BIOS revision, etc., as reported by Linux under `/sys/class/dmi/id/`.
Address, Port (Network interface OS devices)
  The MAC address and the port number of a software network interface, such as `eth4` on Linux.
NodeGUID, SysImageGUID, Port1State, Port2LID, Port2LMC, Port3GID1 (OpenFabrics OS devices)
  The node GUID and GUID mask, the state of a port #1 (value is 4 when active), the LID and LID mask count of port #2, and GID #1 of port #3.
Type
  A better type name than the usual one. This may be used to specify where Groups come from. For instance Linux s390 books appear as Groups of type Book. Block OS devices may have a Type of "Disk", "Tape", "Removable Media Device" or "Other". The Type attribute value is displayed instead of the default object type name in lstopo.
Vendor, AssetTag, PartNumber, DeviceLocation, BankLocation (MemoryDevice Misc objects)
  Information about memory devices (DIMMs) extracted from SMBIOS.
hwlocVersion
  The version number of the hwloc library that was used to generate the topology. If the topology was loaded from XML, this is not the hwloc version that loaded it, but rather the first hwloc instance that exported the topology to XML earlier.
ProcessName
  The name of the process that contains the hwloc library that was used to generate the topology. If the topology was from XML, this is not the hwloc version that loaded it, but rather the first process that exported the topology to XML earlier.

Here is a non-exhaustive list of user-provided info attributes that have a special meaning:

lstopoStyle
  Enforces the style of an object (background and text colors) in the graphical output of lstopo. See CUSTOM COLORS in the lstopo(1) manpage for details.