77 results about "Interrupt latency" patented technology

Status / error reporting is implemented using a doorbell system. A plurality of flag registers are included on a system device, such as a serial buffer. Each flag register has a corresponding address, and stores a plurality of flags. A flag scan controller accesses the flag registers in a predetermined priority order, using the flag register addresses. Upon detecting that one or more of the flags of a flag register are activated, the flag scan controller causes a doorbell command to be generated. The doorbell command includes the flag register address and the corresponding flags. A system processor receives the doorbell command and services the activated flags. Once the activated flags are serviced, the system processor performs one or more software write operations to clear the flags within the system device. The system processor can simultaneously service multiple flags. The system processor can also simultaneously clear multiple flags.

The present invention provides a data processing apparatus and method for saving return state. The data processing apparatus comprises a processing unit for executing data processing instructions, the processing unit having a plurality of modes of operation, with each mode of operation having a corresponding stack for storing data associated with that mode. The processing unit is responsive to a return state data processing instruction to write return state data of the processing unit from its current mode of operation to a stack corresponding to a different mode of operation to the current mode of operation. This approach significantly reduces code size and improves interrupt latency over known prior art techniques.

A method provides adaptive interrupt latency to improve performance in a processing system. A ration of transmit queue depth to receive queue depth of the adapter is compared to its historical value in order to provide an estimate of processor load. The estimated processor load is then used to set a parameter that controls the frequency of an interrupt generator, which may be controlled by setting an interrupt queue depth threshold, packet frequency threshold or interrupt hold-off time value. The historical value may be predetermined, user-settable, obtained during a calibration interval or obtained by taking a long-term average of the ratio.

A data processing apparatus is described which comprises processing circuitry responsive to data processing instructions to execute integer data processing operations and floating point data processing operations, a first set of integer registers useable by the processing circuitry in executing the integer data processing operations, and a second set of floating point registers useable by the processing circuitry in executing the floating point data processing operations. The processing circuitry is responsive to an interrupt request to perform one of an integer state preservation function in which at least a subset of only the integer registers are copied to a stack memory, and a floating point state preservation function in which at least a subset of both the integer registers and the floating point registers are copied to the stack memory, the one of said integer state preservation function and the floating point state preservation function being selected by the processing circuitry in dependence on state information. In this way, it is possible to reduce the memory size requirement through reduced stack sizes, and to reduce the number of memory accesses required compared with the basic solution of always preserving floating point registers. As a result, power usage and interrupt latency can be reduced.