Abstract: A method for improving performance of a host bus adapter in a data storage system is disclosed. In one embodiment, such a method uses, as an interface to a memory controller contained within a host bus adapter, multiple two-way ports configured to operate in parallel. The method uses, within each two-way port, a read FIFO buffer for transferring read data across the two-way port and a write FIFO buffer for transferring write data across the two-way port. The method also uses the read FIFO buffer and the write FIFO buffer within each two-way port to provide speed-matching for different clock speeds that operate on opposite sides of the two-way port. A corresponding system and computer program product are also disclosed.

Abstract: A method for improving performance of a direct memory access (DMA) transfer is disclosed. The method generates a descriptor that describes parameters of a DMA transfer to be performed by a DMA engine, such as a DMA engine within a host bus adapter of a data storage system. The method provides, in the descriptor, a field that describes an operation to be performed by the DMA engine. The field has as options an echo read operation, a dual write operation, a loop DDs operation, and a normal DMA transfer operation. The method provides the descriptor to the DMA engine. The DMA engine extracts the operation from the field and performs the operation. This operation may, in certain embodiments, move data through a host bus adapter of a data storage system. A corresponding system and computer program product are also disclosed.

Abstract: A method for improving performance of a host bus adapter in a data storage system is disclosed. In one embodiment, such a method uses, as an interface to a memory controller contained within a host bus adapter, multiple two-way ports configured to operate in parallel. The method uses, within each two-way port, a read FIFO buffer for transferring read data across the two-way port and a write FIFO buffer for transferring write data across the two-way port. The method also uses the read FIFO buffer and the write FIFO buffer within each two-way port to provide speed-matching for different clock speeds that operate on opposite sides of the two-way port. A corresponding system and computer program product are also disclosed.

Abstract: An apparatus, system, and method are provided for managing errors in prefetched data. The apparatus, system, and method identify prefetched data that contains an uncorrectable error. In addition, the apparatus, system, and method initiate an error recovery process only for prefetched data that is actually used by a requesting device, module, or application. The apparatus includes a prefetch module that prefetches data packets, a validation module that determines whether a prefetched data packet contains an uncorrectable error, a transfer module that transfers prefetched data packets to a requester, and an error recovery module that selectively initiates error recovery for those data packets that contain an uncorrectable error and are actually transferred to the requester.

Abstract: A diagnostic tracing logger is presented for use in a multithread environment in which diagnostic trace log entries are captured and recorded. The trace logs are composed of sequences of memory addresses used to access instructions and operands, instruction op-codes and register specifiers, sequences of memory addresses, branch instructions or exceptions, the contents of registers or semiconductor memory locations, and the like. In one embodiment, a software module configures a plurality of buffers to capture bus traces, each trace triggered by a specific pattern. A buffer controller manages transfer of diagnostic trace information from the plurality of buffers to a diagnostic log without using processor memory cycles. The trace information is transferred to a selected buffer using a processor cache flush instruction. Diagnostic trace logging facilitates diagnosis of complex system and software interactions without the cost and overhead of prior art trace logging techniques.

Abstract: A diagnostic tracing logger is presented for use in a multithread environment in which diagnostic trace log entries are captured and recorded. The trace logs are composed of sequences of memory addresses used to access instructions and operands, instruction op-codes and register specifiers, sequences of memory addresses, branch instructions or exceptions, the contents of registers or semiconductor memory locations, and the like. In one embodiment, a software module configures a plurality of buffers to capture bus traces, each trace triggered by a specific pattern. A buffer controller manages transfer of diagnostic trace information from the plurality of buffers to a diagnostic log without using processor memory cycles. The trace information is transferred to a selected buffer using a processor cache flush instruction. Diagnostic trace logging facilitates diagnosis of complex system and software interactions without the cost and overhead of prior art trace logging techniques.

Abstract: An apparatus, system, and method are provided for managing errors in prefetched data. The apparatus, system, and method identify prefetched data that contains an uncorrectable error. In addition, the apparatus, system, and method initiate an error recovery process only for prefetched data that is actually used by a requesting device, module, or application. The apparatus includes a prefetch module that prefetches data packets, a validation module that determines whether a prefetched data packet contains an uncorrectable error, a transfer module that transfers prefetched data packets to a requester, and an error recovery module that selectively initiates error recovery for those data packets that contain an uncorrectable error and are actually transferred to the requester.

Abstract: A high speed interrupt controller and interrupt discrimination scheme for a data communication system is provided, usable in a subsystem of a data communication system. The controller and its scheme may be used for expanding the number of interrupts to be efficiently received and discriminated by a processor having a limited number of interrupt input lines. The present invention can be used for optimizing the management of data within a shared bus with multiple masters, wherein a shared bus is connected to a plurality of bus masters and corresponding slaves and located between an external bus connected to a system processor, and an internal bus connected to an internal processor. The architecture utilizes the high speed interrupt controller device having a circuitry which has a plurality of interrupt lines and may have one output line and a control code, located in the device interrupt handler.

Abstract: A shared bus hang prevention and recovery scheme for a data communication system is provided, where a shared bus is connected to a plurality of bus masters and corresponding slaves and located between an external bus connected to a system processor, and an internal bus connected to an internal processor. Some of the masters are associated with the external bus and others are associated with the internal bus, and one of the bus masters is a control master associated with the internal processor. The scheme utilizes a shared bus hang prevention and recovery device having a circuitry and a control code. The circuitry is timing each pending request of the control master for the shared bus and initiating bus recovery if the shared bus is hung up, when the control master exceeded a pre-determined time period allowed for waiting to acquire the shared bus control and complete the transfer on the shared bus.