Abstract: A method is directed to use of a master root node, in a distributed computer system provided with multiple root nodes, to control the configuration of routings through an I/O switched-fabric. One of the root nodes is designated as the master root node or PCI Configuration Manager (PCM), and is operable to carry out the configuration while each of the other root nodes remains in a quiescent or inactive state. In one useful embodiment pertaining to a system of the above type, that includes multiple root nodes, PCI switches, and PCI adapters available for sharing by different root nodes, a method is provided wherein the master root node is operated to configure routings through the PCI switches. Respective routings are configured between respective root nodes and the PCI adapters, wherein each of the configured routings corresponds to only one of the root nodes.

Abstract: A method and apparatus is provided for routing error messages in a distributed computer system comprising multiple root nodes, and further comprising one or more PCI switches and one or more I/O adapters, wherein each root node includes one or more system images. In one useful embodiment, a method is provided for routing I/O error messages to root nodes respectively associated with the errors contained in the messages. The method includes detecting occurrence of an error at a specified one of the adapters, wherein the error affects one of the system images, and generating an error message at the specified adapter. The method further comprises routing the error message from the specified adapter to the particular root node that includes the affected system image. The error message is then selectively processed at the particular root node, in order to identify the affected system image.

Abstract: A method, mechanism and computer usable medium is provided for distributing I/O fabric errors to the appropriate root nodes in a multi-root environment. The case where the I/O fabric is attached to more than one root node and where each root can potentially share with the other roots the I/O adapter (IOA) resources which are attached to the I/O is addressed. Additionally, a method, mechanism and computer usable medium is provided by which errors detected in an I/O fabric may be routed to all root nodes which may be affected by the error, while not being reported to the root nodes that will not be affected by those errors. In particular, distributed computing system which uses the PCI Express protocol to communicate over the I/O fabric is addressed.

Abstract: A mechanism, method and computer usable medium is provided for each root node of a multiple root node system and its own independent address space. This mechanism also allows multiple system images within the same root node to have their own independent address spaces. A mechanism is also provided for incorporating legacy root node and input/output adapters that are non-aware of the mechanisms introduced by this invention. Input/ output adapters which implement this invention may also have the number of functions that they support greatly expanded beyond the present eight functions per input/output adapter.

Abstract: A number of improvements in network adapters that offload protocol processing from the host processor are provided. Specifically, a mechanism for improving connection establishment in a system utilizing an offload network adapter is provided. The connection establishment mechanism provides the ability to offload connection establishment and maintenance of connection state information to the offload network adapter. As a result of this offloading of connection establishment and state information maintenance, the number of communications needed between the host system and the offload network adapter may be reduced. In addition, offloading of these functions to the offload network adapter permits bulk notification of established connections and state information to the host system rather than piecemeal notifications as is present in known computing systems.

Abstract: A number of improvements in network adapters that offload protocol processing from the host processor are provided. Specifically, mechanisms for handling memory management and optimization within a system utilizing an offload network adapter are provided. The memory management mechanism permits both buffered sending and receiving of data as well as zero-copy sending and receiving of data. In addition, the memory management mechanism permits grouping of DMA buffers that can be shared among specified connections based on any number of attributes. The memory management mechanism further permits partial send and receive buffer operation, delaying of DMA requests so that they may be communicated to the host system in bulk, and expedited transfer of data to the host system.

Abstract: A number of improvements in network adapters that offload protocol processing from the host processor are provided. Specifically, an improved mechanism for handling receipt of data packets in a system utilizing an offload network adapter. The offload network adapter may include logic that permits the offload network adapter to delay notification of data reception to the host system in different ways. The advantage of delaying the notice of data packet reception to the host system is the potential for aggregation of several data packets, which can arrive immediately after the first one, for example, in a single notification. Given a stream with continuous data packet arrival, a value may be set, either statically or dynamically, for notification delay and this value may be configurable for the host system per communication socket.

Abstract: A method, apparatus, and computer instructions for transferring data objects. A request for a data object is received at a communication adapter. A determination is made as to whether the data object is stored in a memory in the communication adapter in response to receiving the request. The data object is transferred from the memory to a receiver of the data object through the communication adapter in which transfer of the data across a bus connecting the communication adapter to the data processing system is unnecessary in response to the data object being present in the memory.

Abstract: A mechanism for bottleneck avoidance is provided in an intelligent adapter. The mechanism allows the adapter to be used such that host/adapter system throughput is optimized. The bottleneck avoidance mechanism of the present invention determines when the adapter becomes a bottleneck. If certain conditions exist, then new connections are refused so that the adapter can process packets for existing connections. If certain other conditions exist, the adapter may migrate workload to the host processor for processing. These conditions may be determined by comparing memory usage or central processing unit usage to predetermined thresholds. Alternatively, the conditions may be determined by comparing adapter response time to host response time.

Abstract: A method, apparatus, and computer instructions for transferring data objects. A request for a data object is received at a communication adapter. A determination is made as to whether the data object is stored in a memory in the communication adapter in response to receiving the request. The data object is transferred from the memory to a receiver of the data object through the communication adapter in which transfer of the data across a bus connecting the communication adapter to the data processing system is unnecessary in response to the data object being present in the memory.