Abstract: A data processing system has an execution pipeline with programmable execution stages which execute instructions to perform data processing operations provided by a host processor and in which execution threads are grouped together into groups in which the threads are executed in lockstep. The system also includes a compiler that compiles programs to generate instructions for the execution stages. The compiler is configured to, for an operation that comprises a memory transaction: issue to the execution stage instructions for executing the operation for the thread group to: perform the operation for the thread group as a whole; and provide the result of the operation to all the active threads of the group. At least one execution stage is configured to, in response to the instructions: perform the operation for the thread group as a whole; and provide the result of the operation to all the active threads of the group.

Abstract: A graphics processing unit comprises a programmable execution unit executing graphics processing programs for execution threads to perform graphics processing operations, a local register memory comprising one or more registers, where registers of the register memory are assignable to store data associated with an individual execution thread that is being executed by the execution unit, and where the register(s) assigned to an individual execution thread are accessible only to that associated individual execution thread, and a further local memory that is operable to store data for use in common by plural execution threads, where the data stored in the further local memory is accessible to plural execution threads as they execute. The programmable execution unit is operable to selectively store output data for an execution thread in a register(s) of the local register memory assigned to the execution thread, and the further local memory.

Abstract: A graphics processing unit comprises a programmable execution unit executing graphics processing programs for execution threads to perform graphics processing operations, a local register memory comprising one or more registers, where registers of the register memory are assignable to store data associated with an individual execution thread that is being executed by the execution unit, and where the register(s) assigned to an individual execution thread are accessible only to that associated individual execution thread, and a further local memory that is operable to store data for use in common by plural execution threads, where the data stored in the further local memory is accessible to plural execution threads as they execute. The programmable execution unit is operable to selectively store output data for an execution thread in a register(s) of the local register memory assigned to the execution thread, and the further local memory.

Abstract: A data processing system has an execution pipeline with programmable execution stages which execute instructions to perform data processing operations provided by a host processor and in which execution threads are grouped together into groups in which the threads are executed in lockstep. The system also includes a compiler that compiles programs to generate instructions for the execution stages. The compiler is configured to, for an operation that comprises a memory transaction: issue to the execution stage instructions for executing the operation for the thread group to: perform the operation for the thread group as a whole; and provide the result of the operation to all the active threads of the group. At least one execution stage is configured to, in response to the instructions: perform the operation for the thread group as a whole; and provide the result of the operation to all the active threads of the group.

Abstract: A processing apparatus comprising: several processors for processing data; a hierarchical memory system comprising a memory accessible to all the processors, and several caches corresponding to each of the processors, each of the caches being accessible to the corresponding processor and comprising storage locations and corresponding indicators. There is also cache coherency control circuitry for maintaining coherency of data stored in the hierarchical memory system. The processors are configured to respond to receipt of a predefined request to perform an operation on a data item to determine if the cache corresponding to the processor receiving the request has a storage location allocated to the data item. If not, the processing apparatus is configured to: allocate a storage location within the cache to the data item, set the indicator corresponding to the storage location to indicate that the storage location is storing a delta value, set data in the allocated storage location to an initial value.

Abstract: A processing apparatus comprising: several processors for processing data; a hierarchical memory system comprising a memory accessible to all the processors, and several caches corresponding to each of the processors, each of the caches being accessible to the corresponding processor and comprising storage locations and corresponding indicators. There is also cache coherency control circuitry for maintaining coherency of data stored in the hierarchical memory system. The processors are configured to respond to receipt of a predefined request to perform an operation on a data item to determine if the cache corresponding to the processor receiving the request has a storage location allocated to the data item. If not, the processing apparatus is configured to: allocate a storage location within the cache to the data item, set the indicator corresponding to the storage location to indicate that the storage location is storing a delta value, set data in the allocated storage location to an initial value.