Rapid Input/Output Doorbell Coalescing To minimize CPU Utilization And Reduce System Interrupt Latency

摘要

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.