Abstract: A cache includes an upstream port, a cache memory for storing cache lines each having a line width, and a cache controller. The cache controller is coupled to the upstream port and the cache memory. The upstream port transfers data words having a transfer width less than the line width. In response to a cache line fill, the cache controller selectively determines data bus inversion information for a sequence of data words having the transfer width, and stores the data bus inversion information along with selected inverted data words for the cache line fill in the cache memory.

Abstract: A method for controlling a data processing system includes detecting a droop in a power supply voltage of a functional circuit of the data processing system greater than a programmable droop threshold. An operation of the data processing system is throttled according to a programmable step size, a programmable assertion time, and a programmable de-assertion time in response to detecting the droop.

Abstract: Systems, methods, and techniques are provided for a fabric addressable memory. A memory access request is received from a host computing device attached via one edge port of one or more interconnect switches, the memory access request directed to a destination segment of a physical fabric memory block that is allocated in local physical memory of the host computing device. The edge port accesses a stored mapping between segments of the physical fabric memory block and one or more destination port identifiers that are each associated with a respective edge port of the fabric addressable memory. The memory access request is routed by the one edge port to a destination edge port based on the stored mapping.

Abstract: Systems and methods for coordinated memory-side cache prefetching and dynamic interleaving configuration modification involve modifying one or both of the prefetch distance or the prefetch degree used by prefetcher modules of one or more memory-side caches by modifying interleaving configuration data following detection of an interleaving reconfiguration trigger condition indicative, for example, of low prefetch accuracy, low prefetch coverage, high prefetch lateness, or a combination of these. In response an interleaving reconfiguration trigger condition, a processor modifies the interleaving configuration data for the processing system based on the prefetch performance characteristics associated with the interleaving reconfiguration trigger condition. In some embodiments, the interleaving configuration data is modified by changing which physical memory address indices are used to determine the bits that define the channel identification number to which that physical memory address is to be mapped.

Abstract: Systems, apparatuses, and methods for performing efficient memory accesses for a computing system are disclosed. In various embodiments, a computing system includes a computing resource and a memory controller coupled to a memory device. The computing resource selectively generates a hint that includes a target address of a memory request generated by the processor. The hint is sent outside the primary communication fabric to the memory controller. The hint conditionally triggers a data access in the memory device. When no page in a bank targeted by the hint is open, the memory controller processes the hint by opening a target page of the hint without retrieving data. The memory controller drops the hint if there are other pending requests that target the same page or the target page is already open.

Abstract: Systems, apparatuses, and methods for performing efficient memory accesses for a computing system are disclosed. In various embodiments, a computing system includes a computing resource and a memory controller coupled to a memory device. The computing resource selectively generates a hint that includes a target address of a memory request generated by the processor. The hint is sent outside the primary communication fabric to the memory controller. The hint conditionally triggers a data access in the memory device. When no page in a bank targeted by the hint is open, the memory controller processes the hint by opening a target page of the hint without retrieving data. The memory controller drops the hint if there are other pending requests that target the same page or the target page is already open.

Abstract: A method of controlling a cache is disclosed. The method comprises receiving a request to allocate a portion of memory to store data. The method also comprises directly mapping a portion of memory to an assigned contiguous portion of the cache memory when the request to allocate a portion of memory to store the data includes a cache residency request that the data continuously resides in cache memory. The method also comprises mapping the portion of memory to the cache memory using associative mapping when the request to allocate a portion of memory to store the data does not include a cache residency request that data continuously resides in the cache memory.

Abstract: Systems, apparatuses, and methods for maintaining region-based cache directories split between node and memory are disclosed. The system with multiple processing nodes includes cache directories split between the nodes and memory to help manage cache coherency among the nodes' cache subsystems. In order to reduce the number of entries in the cache directories, the cache directories track coherency on a region basis rather than on a cache line basis, wherein a region includes multiple cache lines. Each processing node includes a node-based cache directory to track regions which have at least one cache line cached in any cache subsystem in the node. The node-based cache directory includes a reference count field in each entry to track the aggregate number of cache lines that are cached per region. The memory-based cache directory includes entries for regions which have an entry stored in any node-based cache directory of the system.

Abstract: Systems, devices, and methods for direct memory access. A system direct memory access (SDMA) device disposed on a processor die sends a message which includes physical addresses of a source buffer and a destination buffer, and a size of a data transfer, to a data fabric device. The data fabric device sends an instruction which includes the physical addresses of the source and destination buffer, and the size of the data transfer, to first agent devices. Each of the first agent devices reads a portion of the source buffer from a memory device at the physical address of the source buffer. Each of the first agent devices sends the portion of the source buffer to one of second agent devices. Each of the second agent devices writes the portion of the source buffer to the destination buffer.

Abstract: Systems, apparatuses, and methods for maintaining region-based cache directories split between node and memory are disclosed. The system with multiple processing nodes includes cache directories split between the nodes and memory to help manage cache coherency among the nodes' cache subsystems. In order to reduce the number of entries in the cache directories, the cache directories track coherency on a region basis rather than on a cache line basis, wherein a region includes multiple cache lines. Each processing node includes a node-based cache directory to track regions which have at least one cache line cached in any cache subsystem in the node. The node-based cache directory includes a reference count field in each entry to track the aggregate number of cache lines that are cached per region. The memory-based cache directory includes entries for regions which have an entry stored in any node-based cache directory of the system.

Abstract: Systems, apparatuses, and methods for efficient data transfer in a computing system are disclosed. A source generates packets to send across a communication fabric (or fabric) to a destination. The source generates partition enable signals for the partitions of payload data. The source negates an enable signal for a particular partition when the source determines the packet type indicates the particular partition should have an associated asserted enable signal in the packet, but the source also determines the particular partition includes a particular data pattern. Routing components of the fabric disable clock signals to storage elements assigned to store the particular partition. The destination inserts the particular data pattern for the particular partition in the payload data.

Abstract: A processing system that includes a shared data fabric resets a first client processor while operating a second client processor. The first client processor is instructed to stop making requests to one or more devices of the shared data fabric. Status communications are blocked between the first client processor and a memory controller, the second client processor, or both, such that the first client processor enters a temporary offline state. The first client processor is indicated as being non-coherent. Accordingly, when the processor is reset some errors and efficiency losses due messages sent during or prior to the reset are prevented.

Abstract: A system for combining write transactions of a large write includes a processor including at least a first die and a second die, and a link coupling the first die and the second die. When a link interface on one die transmits packets to the other die over the link, the link interface identifies, from a queue containing a plurality of write transactions, two or more write transactions in the queue that are candidates for combination based on one or more attributes of each write transaction. The link interface determines whether two or more candidate write transactions are combinable based on a set of conditions. When two or more candidate write transaction are combinable, the link interface combines the candidate write transactions into a single combined write transaction and transmits the combined write transaction.

Abstract: Dynamic network-on-chip traffic throttling, including: determining, by a detector module of a network-on-chip, that a predefined condition is met; sending, by the detector module, a signal to a mediator module of the network-on-chip; and sending, in response to the signal, by the mediator module, an indication to a plurality of agents to implement a traffic throttling policy.

Abstract: Systems, apparatuses, and methods for routing interrupts on a coherency probe network are disclosed. A computing system includes a plurality of processing nodes, a coherency probe network, and one or more control units. The coherency probe network carries coherency probe messages between coherent agents. Interrupts that are detected by a control unit are converted into messages that are compatible with coherency probe messages and then routed to a target destination via the coherency probe network. Interrupts are generated with a first encoding while coherency probe messages have a second encoding. Cache subsystems determine whether a message received via the coherency probe network is an interrupt message or a coherency probe message based on an encoding embedded in the received message. Interrupt messages are routed to interrupt controller(s) while coherency probe messages are processed in accordance with a coherence probe action field embedded in the message.

Abstract: Disclosed are examples of a system and method to communicate cache line eviction data from a CPU subsystem to a home node over a prioritized channel and to release the cache subsystem early to process other transactions.

Abstract: A method includes, in response to each write request of a plurality of write requests received at a memory-side cache device coupled with a memory device, writing payload data specified by the write request to the memory-side cache device, and when a first bandwidth availability condition is satisfied, performing a cache write-through by writing the payload data to the memory device, and recording an indication that the payload data written to the memory-side cache device matches the payload data written to the memory device.

Abstract: Systems, apparatuses, and methods for efficient data transfer in a computing system are disclosed. A source generates packets to send across a communication fabric (or fabric) to a destination. The source generates partition enable signals for the partitions of payload data. The source negates an enable signal for a particular partition when the source determines the packet type indicates the particular partition should have an associated asserted enable signal in the packet, but the source also determines the particular partition includes a particular data pattern. Routing components of the fabric disable clock signals to storage elements assigned to store the particular partition. The destination inserts the particular data pattern for the particular partition in the payload data.

Abstract: A method of controlling a cache is disclosed. The method comprises receiving a request to allocate a portion of memory to store data. The method also comprises directly mapping a portion of memory to an assigned contiguous portion of the cache memory when the request to allocate a portion of memory to store the data includes a cache residency request that the data continuously resides in cache memory. The method also comprises mapping the portion of memory to the cache memory using associative mapping when the request to allocate a portion of memory to store the data does not include a cache residency request that data continuously resides in the cache memory.

Abstract: Systems, apparatuses, and methods for maintaining a region-based cache directory are disclosed. A system includes multiple processing nodes, with each processing node including a cache subsystem. The system also includes a cache directory to help manage cache coherency among the different cache subsystems of the system. In order to reduce the number of entries in the cache directory, the cache directory tracks coherency on a region basis rather than on a cache line basis, wherein a region includes multiple cache lines. Accordingly, the system includes a region-based cache directory to track regions which have at least one cache line cached in any cache subsystem in the system. The cache directory includes a reference count in each entry to track the aggregate number of cache lines that are cached per region. If a reference count of a given entry goes to zero, the cache directory reclaims the given entry.