Abstract: Message passing circuitry comprises lookup circuitry responsive to a producer request indicating message data provided on a target message channel by a producer node of a system-on-chip, to obtain, from a channel consumer information structure, selected channel consumer information associated with a given consumer node subscribing to the target message channel. Control circuitry writes the message data to a location associated with an address in a consumer-defined region of address space determined based on the selected channel consumer information. When an event notification condition is satisfied for the target message channel and the given consumer node, and an event notification channel is to be used, event notification data is written to a location associated with an address in a consumer-defined region of address space determined based on event notification channel consumer information associated with the event notification channel.

Abstract: Circuitry comprises a set of data handling nodes comprising: two or more master nodes each having respective storage circuitry to hold copies of data items from a main memory, each copy of a data item being associated with indicator information to indicate a coherency state of the respective copy, the indicator information being configured to indicate at least whether that copy has been updated more recently than the data item held by the main memory; a home node to serialise data access operations and to control coherency amongst data items held by the set of data handling nodes so that data written to a memory address is consistent with data read from that memory address in response to a subsequent access request; and one or more slave nodes including the main memory; in which: a requesting node of the set of data handling nodes is configured to communicate a conditional request to a target node of the set of data handling nodes in respect of a copy of a given data item at a given memory address, the condit

Abstract: A system, apparatus and method for ordering a sequence of processing transactions. The method includes accessing, from a memory, a program sequence of operations that are to be executed. Instructions are received, some of them having an identifier, or mnemonic, that is used to distinguish those identified operations from other operations that do not have an identifier, or mnemonic. The mnemonic indicates a distribution of the execution of the program sequence of operations. The program sequence of operations is grouped based on the mnemonic such that certain operations are separated from other operations.

Abstract: In a cache stash relay, first data, from a producer device, is stashed in a shared cache of a data processing system. The first data is associated with first data addresses in a shared memory of the data processing system. An address pattern of the first data addresses is identified. When a request for second data, associated with a second data address, is received from a processing unit of the data processing system, any data associated with data addresses in the identified address pattern are relayed from the shared cache to a local cache of the processing unit if the second data address is in the identified address pattern. The relaying may include pushing the data from the shared cache to the local cache or a pre-fetcher of the processing unit pulling the data from the shared cache to the local cache in response to a message.

Abstract: A data processing system includes a processor, a memory system, a cache controller and a cache accessible by the processor via the cache controller. The cache controller provides an asynchronous interface between the processor and the memory system. Instructions, issued by the processor to the cache controller, are completed by the cache controller without blocking the processor. In addition, the cache controller tracks a completion status of the memory operation associated with each instruction and enables the completion status to be queried by the processor. Status of the memory operation may be recorded as an entry in a log, where the log, or a property of the log, is accessible by the processor.

Abstract: A method and apparatus for monitoring cache transactions in a cache of a data processing system is provided. Responsive to a cache transaction associated with a transaction address, when a cache controller determines that the cache transaction is selected for monitoring, the cache controller retrieves a pointer stored in a register, determines a location in a log memory from the pointer, and writes a transaction identifier to the determined location in the log memory. The transaction identifier is associated with the transaction address and may be a virtual address, for example. The pointer is updated and stored to the register. The architect of the apparatus may include a mechanism for atomically combining data access instructions with an instruction to commence monitoring.

Abstract: Circuitry comprises a set of data handling nodes comprising: two or more master nodes each having respective storage circuitry to hold copies of data items from a main memory, each copy of a data item being associated with indicator information to indicate a coherency state of the respective copy, the indicator information being configured to indicate at least whether that copy has been updated more recently than the data item held by the main memory; a home node to serialise data access operations and to control coherency amongst data items held by the set of data handling nodes so that data written to a memory address is consistent with data read from that memory address in response to a subsequent access request; and one or more slave nodes including the main memory; in which: a requesting node of the set of data handling nodes is configured to communicate a conditional request to a target node of the set of data handling nodes in respect of a copy of a given data item at a given memory address, the condit

Abstract: A system, apparatus and method for accessing an electronic storage medium, such as a memory location storing a page table, or range table. A virtual address of the electronic storage medium is identified that corresponds to designated portions, such as a range of addresses of the electronic storage medium. The virtual address is translated to a corresponding physical address and one or more commands are identified as being excluded from execution in the designated portions of the electronic storage medium. This may be accomplished by using a routine such as mprotect( ). A fault indication, or decoration, is provided to meta-data associated with the physical address, which is associated with the designated portions of the electronic storage medium when excluded commands are provided to the physical address. A mechanism, such as hardware, is actuated when the fault is generated.

Abstract: A data processing system includes a processor, a memory system, a cache controller and a cache accessible by the processor via the cache controller. The cache controller provides an asynchronous interface between the processor and the memory system. Instructions, issued by the processor to the cache controller, are completed by the cache controller without blocking the processor. In addition, the cache controller tracks a completion status of the memory operation associated with each instruction and enables the completion status to be queried by the processor. Status of the memory operation may be recorded as an entry in a log, where the log, or a property of the log, is accessible by the processor.

Abstract: A method and apparatus for monitoring cache transactions in a cache of a data processing system is provided. Responsive to a cache transaction associated with a transaction address, when a cache controller determines that the cache transaction is selected for monitoring, the cache controller retrieves a pointer stored in a register, determines a location in a log memory from the pointer, and writes a transaction identifier to the determined location in the log memory. The transaction identifier is associated with the transaction address and may be a virtual address, for example. The pointer is updated and stored to the register. The architect of the apparatus may include a mechanism for atomically combining data access instructions with an instruction to commence monitoring.

Abstract: An apparatus has processing circuitry for processing instructions from multiple threads. A storage structure is shared between the threads and has a number of entries. Indexing circuitry generates a target index value identifying an entry of the storage structure to be accessed in response to a request from the processing circuitry specifying a requested index value corresponding to information to be accessed from the storage structure. The indexing circuitry generates the target index value as a function of the requested index value and a key value selected depending on which of the threads trigger the request. The key value for at least one of the threads is updated from time to time.

Abstract: A system, apparatus and method for accessing an electronic storage medium, such as a memory location storing a page table, or range table. A virtual address of the electronic storage medium is identified that corresponds to designated portions, such as a range of addresses of the electronic storage medium. The virtual address is translated to a corresponding physical address and one or more commands are identified as being excluded from execution in the designated portions of the electronic storage medium. This may be accomplished by using a routine such as mprotect( ). A fault indication, or decoration, is provided to meta-data associated with the physical address, which is associated with the designated portions of the electronic storage medium when excluded commands are provided to the physical address. A mechanism, such as hardware, is actuated when the fault is generated.

Abstract: Data processing apparatus comprises one or more interconnected processing elements; each processing element being configured to execute processing instructions of program tasks; each processing element being configured to save context data relating to a program task following execution of that program task by that processing element; and to load context data, previously saved by that processing element or another of the processing elements, at resumption of execution of a program task; each processing element having respective associated format definition data to define one or more sets of data items for inclusion in the context data; the apparatus comprising format selection circuitry to communicate the format definition data of each of the processing elements with others of the processing elements and to determine, in response to the format definition data for each of the processing elements, a common set of data items for inclusion in the context data.

Abstract: A method and apparatus are provided for dynamically determining when an operation, specified by one or more instructions in a data processing system, is suitable for accelerated execution. Data indicators are maintained, for data registers of the system, that indicate when data-flow from a register derives from a restricted source. In addition, instruction predicates are provided for instructions to indicate which instructions are capable of accelerated execution. From the data indicators and the instruction predicates, the microarchitecture of the data processing system determines, dynamically, when the operation is a thread-restricted function and suitable for accelerated execution in a hardware accelerator. The thread-restricted function may be executed on a hardware processor, such as a vector, neuromorphic or other processor.

Abstract: A host machine uses a range-based address translation system rather than a conventional page-based system. This enables address translation to be performed with improved efficiency, particularly when nest virtual machines are used. A data processing system utilizes range-based address translation to provide fast address translation for virtual machines that use virtual address space.

Abstract: A system, apparatus and method for ordering a sequence of processing transactions. The method includes accessing, from a memory, a program sequence of operations that are to be executed. Instructions are received, some of them having an identifier, or mnemonic, that is used to distinguish those identified operations from other operations that do not have an identifier, or mnemonic. The mnemonic indicates a distribution of the execution of the program sequence of operations. The program sequence of operations is grouped based on the mnemonic such that certain operations are separated from other operations.

Abstract: A system, apparatus and method are provided in which a range of virtual memory addresses and a copy of that range are mapped to the same first system address range in a data processing system until an address in the virtual memory address range, or its copy, is written to. The common system address range includes a number of divisions. Responsive to a write request to an address in a division of the common address range, a second system address range is generated. The second system address range is mapped to the same physical addresses as the first system address range, except that the division containing the address to be written to and its corresponding division in the second system address range are mapped to different physical addresses. First layer mapping data may be stored in a range table buffer and updated when the second system address range is generated.

Abstract: Data processing apparatus comprises a group of two or more processing elements configured to execute processing instructions of a program task; the processing elements being configured to provide context data relating to a program task following execution of that program task by that processing element; and to receive context data, provided by that processing element or another processing element, at resumption of execution of a program task; in which a next processing element of the group to execute a program task is configured to receive a first subset of the context data from a previous processing element to execute that program task and to start to execute the program task using the first subset of the context data; and in which the next processing element is configured to receive one or more items of a second, remaining, subset of the context data during execution of the program task by that processing element.

Abstract: A data processing network includes a network of devices addressable via a system address space, the network including a computing device configured to execute an application in a virtual address space. A virtual-to-system address translation circuit is configured to translate a virtual address to a system address. A memory node controller has a first interface to a data resource addressable via a physical address space, a second interface to the computing device, and a system-to-physical address translation circuit, configured to translate a system address in the system address space to a corresponding physical address in the physical address space of the data resource. The virtual-to-system mapping may be a range table buffer configured to retrieve a range table entry comprising an offset address of a range together with a virtual address base and an indicator of the extent of the range.

Abstract: A memory address translation apparatus comprises a translation data store to store one or more instances of translation data. Each instance provides address range boundary values defining a range of virtual memory addresses between respective virtual memory address boundaries in a virtual memory address space, and indicates a translation between a virtual memory address in the range of virtual memory addresses and a corresponding output memory address in an output address space. When a given virtual memory address to be translated lies outside the ranges of virtual memory addresses defined by any instances of the translation data stored by the translation data store, detector circuitry retrieves one or more further instances of the translation data and translation circuitry applies the translation defined by a detected instance of the translation data to the given virtual memory address.