Abstract: A distributed data processing system executes multiple tasks within a parallel job, including a first local task on a local node and at least one task executing on a remote node, with a remote memory having real address (RA) locations mapped to one or more of the source effective addresses (EA) and destination EA of a data move operation initiated by a task executing on the local node. On initiation of the data move operation, remote asynchronous data move (RADM) logic identifies that the operation moves data to/from a first EA that is memory mapped to an RA of the remote memory. The local processor/RADM logic initiates a RADM operation that moves a copy of the data directly from/to the first remote memory by completing the RADM operation using the network interface cards (NICs) of the source and destination processing nodes, determined by accessing a data center for the node IDs of remote memory.

Abstract: A system and method for specifying an access hint for prefetching only a subsection of cache block data, for more efficient system interconnect usage by the processor core. A processing unit receives a data cache block touch (DCBT) instruction containing an access hint and identifying a specific size portion of data to be prefetched. Both the access hint and a value corresponding to an amount of data to be prefetched are contained in separate subfields of the DCBT instruction. In response to detecting that the code point is set to a specific value, only the specific size of data identified in a sub-field of the DCBT and addressed in the DCBT instruction is prefetched into an entry in the lower level cache.

Abstract: A method, computer program product, and system are provided performing a Message Passing Interface (MPI) job. A first processor chip receives a set of arrival signals from a set of processor chips executing tasks of the MPI job in the data processing system. The arrival signals identify when a processor chip executes a synchronization operation for synchronizing the tasks for the MPI job. Responsive to receiving the set of arrival signals from the set of processor chips, the first processor chip identifies a fastest processor chip of the set of processor chips whose arrival signal arrived first. An operation of the fastest processor chip is modified based on the identification of the fastest processor chip. The set of processor chips comprises processor chips that are in one of a same processor book or a different processor book of the data processing system.

Abstract: A mechanism is provided for providing reliability of communication. A first processor determines a current state of links coupled to ports of a first processor of the data processing system. Each port of the first processor comprises a plurality of links to a corresponding port on a second processor of the data processing system. The current state of the links indicates a level of error associated with each link. The first processor determines, for each link, if a level of error associated with the link exceeds a threshold. For each link whose level of error exceeds the threshold, the first processor tags the link with an error identifier in a switch associated with the ports of the first processor. The first processor reduces a level of usage for transmitting data on ports associated with links tagged with the error identifier.

Abstract: A method, computer program product, and system are provided for selecting, from a plurality of routes through the data processing system, an indirect route for transmitting data. Data that includes address information is received at a first processor that is to be transmitted to a destination processor. Using routing table data structures, indirect route entries are identified that correspond to indirect routes for transmitting data. An accessed priority table data structure comprises a priority entry for each entry in the routing table data structures. The priority entry specifies a priority of a corresponding entry in the routing table data structures. An indirect route entry is selected that corresponds to an indirect route from the routing table data structures, based on specified priorities. Then the data is transmitted from the first processor to the destination processor using a path corresponding to the selected indirect route entry.

Abstract: A method, computer program product, and system are provided for selecting, from a plurality of routes through the data processing system, a direct route for transmitting data. Data that includes address information is received at a first processor that is to be transmitted to a destination processor. Using routing table data structures, direct route entries are identified that correspond to direct routes for transmitting data. An accessed priority table data structure comprises a priority entry for each entry in the routing table data structures. The priority entry specifies a priority of a corresponding entry in the routing table data structures. A direct route entry is selected that corresponds to a direct route from the routing table data structures, based on specified priorities. Then the data is transmitted from the first processor to the destination processor using a path corresponding to the selected direct route entry.

Abstract: A computer implemented method, data processing system, and computer program product for nominating rules or policies for promotion through a policy hierarchy. An administrator at any level in a policy hierarchy may create a rule or policy. The administrator may then nominate the rule or policy for inclusion in a next higher level in the policy hierarchy. The rule or policy is evaluated at the next higher level. Responsive to an approval of the next higher level to include the rule or policy in the jurisdiction of the next higher level, the rule of policy is provided to all users under the jurisdiction. The nominating, evaluating, and providing steps may then be repeated for each higher level in the policy hierarchy.

Abstract: In one embodiment, a cache memory includes a cache array including a plurality of entries for caching cache lines of data, where the plurality of entries are distributed between a first region implemented in a first memory technology and a second region implemented in a second memory technology. The cache memory further includes a cache directory of the contents of the cache array and a cache controller that controls operation of the cache memory.

Abstract: A system and method for cache management in a data processing system. The data processing system includes a processor and a memory hierarchy. The memory hierarchy includes at least an upper memory cache, at least a lower memory cache, and a write-back data structure. In response to replacing data from the upper memory cache, the upper memory cache examines the write-back data structure to determine whether or not the data is present in the lower memory cache. If the data is present in the lower memory cache, the data is replaced in the upper memory cache without casting out the data to the lower memory cache.

Abstract: A method and an apparatus for enabling a prefetch engine to detect and support hardware prefetching with different streams in received accesses. Multiple (simple) history tables are provided within (or associated with) the prefetch engine. Each of the multiple tables is utilized to detect different access patterns. The tables are indexed by different parts of the address and are accessed in a preset order to reduce the interference between different patterns. When an address does not fit the patterns of a first table, the address is passed to the next table to be checked for a match of different patterns. In this manner, different patterns may be detected at different tables within a single prefetch engine.

Abstract: A method and data processing system for tracking global shared memory (GSM) operations to and from a local node configured with a host fabric interface (HFI) coupled to a network fabric. During task/job initialization, the system OS assigns HFI window(s) to handle the GSM packet generation and GSM packet receipt and processing for each local task. HFI processing logic automatically tags each GSM packet generated by the HFI window with a global job identifier (ID) of the job to which the local task is affiliated. The job ID is embedded within each GSM packet placed on the network fabric. On receipt of a GSM packet from the network fabric, the HFI logic retrieves the embedded job ID and compares the embedded job ID with the ID within the HFI window(s). GSM packets are forwarded to an HFI window only when the embedded job ID matches the HFI window's job ID.

Abstract: A data processing system enables global shared memory (GSM) operations across multiple nodes with a distributed EA-to-RA mapping of physical memory. Each node has a host fabric interface (HFI), which includes HFI windows that are assigned to at most one locally-executing task of a parallel job. The tasks perform parallel job execution, but map only a portion of the effective addresses (EAs) of the global address space to the local, real memory of the task's respective node. The HFI window tags all outgoing GSM operations (of the local task) with the job ID, and embeds the target node and HFI window IDs of the node at which the EA is memory mapped. The HFI window also enables processing of received GSM operations with valid EAs that are homed to the local real memory of the receiving node, while preventing processing of other received operations without a valid EA-to-RA local mapping.

Abstract: A data processing system enables global shared memory (GSM) operations across multiple nodes with a distributed EA-to-RA mapping of physical memory. Each node has a host fabric interface (HFI), which includes HFI windows that are assigned to at most one locally-executing task of a parallel job. The tasks perform parallel job execution, but map only a portion of the effective addresses (EAs) of the global address space to the local, real memory of the task's respective node. The HFI window tags all outgoing GSM operations (of the local task) with the job ID, and embeds the target node and HFI window IDs of the node at which the EA is memory mapped. The HFI window also enables processing of received GSM operations with valid EAs that are homed to the local real memory of the receiving node, while preventing processing of other received operations without a valid EA-to-RA local mapping.

Abstract: A method for providing global notification of completion of a global shared memory (GSM) operation during processing by a target task executing at a target node of a distributed system. The distributed system has at least one other node on which an initiating task that generated the GSM operation is homed. The target task receives the GSM operation from the initiating task, via a host fabric interface (HFI) window assigned to the target task. The task initiates execution of the GSM operation on the target node. The task detects completion of the execution of the GSM operation on the target node, and issues a global notification to at least the initiating task. The global notification indicates the completion of the execution of the GSM operation to one or more tasks of a single job distributed across multiple processing nodes.

Abstract: A method and data processing system for performing fence operations within a global shared memory (GSM) environment having a local task executing on a processor and providing GSM commands for processing by a host fabric interface (HFI) window that is allocated to the task. The HFI window has one or more registers for use during local fence operations. A first register tracks a first count of task-issued GSM commands, and a second register tracks a second count of GSM operations being processed by the HFI. The processing logic detects a locally-issued fence operation, and responds by performing a series of operations, including: automatically stopping the task from issuing additional GSM commands; monitoring for completion of all the task-issued GSM commands at the HFI; and triggering a resumption of issuance of GSM commands by the task when the completion of all previous task-issued GSM commands is registered by the HFI.

Abstract: A method and a data processing system for completing checkpoint processing of a distributed job with local tasks communicating with other remote tasks via a host fabric interface (HFI) and assigned HFI window. Each HFI window has a send count and a receive count, which tracks GSM messages that are sent from and received at the HFI window. When a checkpoint is initiated by a master task, each local task forwards the send count and the receive count to the master task. The master task sums the respective counts and then compares the totals to each other. When the send count total is equal to the receive count total, the tasks are permitted to continue processing. However, when the send count total is not equal to the receive count total, the master task notifies each task of the job to rollback to a previous checkpoint or kill the job execution.

Abstract: In a global shared memory (GSM) environment, a method provides local notification of completion of a global shared memory (GSM) operation processed by a first task executing at a local node of the distributed system. The system includes multiple nodes on which different tasks of a single job execute and perform GSM operations that are received from a second task via a via host fabric interface (HFI) and associated HFR window assigned to the first tasks. The local task initiates execution of a GSM operation on the local node. The task then monitors for and detects a completion of the execution of the GSM operation on the local node. When the task detects completion of the execution of the GSM operation, the task issues an internal notification to inform the locally-executing tasks of the completion of the GSM operation.

Abstract: A method for issuing global shared memory (GSM) operations from an originating task on a first node coupled to a network fabric of a distributed network via a host fabric interface (HFI). The originating task generates a GSM command within an effective address (EA) space. The task then places the GSM command within a send FIFO. The send FIFO is a portion of real memory having real addresses (RA) that are memory mapped to EAs of a globally executing job. The originating task maintains a local EA-to-RA mapping of only a portion of the real address space of the globally executing job. The task enables the HFI to retrieve the GSM command from the send FIFO into an HFI window allocated to the originating task. The HFI window generates a corresponding GSM packet containing GSM operations and/or data, and the HFI window issues the GSM packet to the network fabric.

Abstract: A host fabric interface (HFI) enables debugging of global shared memory (GSM) operations received at a local node from a network fabric. The local node has a memory management unit (MMU), which provides an effective address to real address (EA-to-RA) translation table that is utilized by the HFI to evaluate when EAs of GSM operations/data from a received GSM packet is memory-mapped to RAs of the local memory. The HFI retrieves the EA associated with a GSM operation/data within a received GSM packet. The HFI forwards the EA to the MMU, which determines when the EA is mapped to RAs within the local memory for the local task. The HFI processing logic enables processing of the GSM packet only when the EA of the GSM operation/data within the GSM packet is an EA that has a local RA translation. Non-matching EAs result in an error condition that requires debugging.

Abstract: A system and method are provided for implementing a two-tier full-graph interconnect architecture. In order to implement a two-tier full-graph interconnect architecture, a plurality of processors are coupled to one another to create a plurality of supernodes. Then, the plurality of supernodes are coupled together to create the two-tier full-graph interconnect architecture. Data is then transmitted from one processor to another within the two-tier full-graph interconnect architecture based on an addressing scheme that specifies at least a supernode and a processor chip identifier associated with a target processor to which the data is to be transmitted.