Fujitsu Corporation

Daisuke Itou

Takashi Yamamoto

Takaharu Ishizuka

Toshikazu Ueki

Makoto Hataida

Yuka Hosokawa

Takeshi Owaki

Hiroshi Nakayama

Junji Ichimiya

Atsushi Morosawa

Shintaro Itozawa

Masaki Ukai

Atsushi Morozawa

A transmitting circuit transmits data to which an error detection code is attached to a receiving circuit via a transmission path. When detecting the error of the data received via the transmission path, a receiving circuit transmits a retransmit request for the data in which the error is detected to the transmitting circuit. The receiving circuit enters a termination unit adjustment period using the error detection of the received data as a trigger and updates the resistance values of a receiving side termination unit installed at the termination of the transmission path to an appropriate value within the termination unit adjustment period.

Transmission device, receiving circuit and control method of transmission device

To prevent a decrease in performance of controlling a snoop tag. A queue is stored with REPLACE target WAY information and an index as an entry associated with a REPLACE request received from a processor, the index stored in the queue is compared with an index of a subsequent READ request, and, as a result of the comparison, a process based on the index-coincident READ request is executed with respect to the snoop tag corresponding to a content of a cache memory of the processor. Further, the REPLACE target WAY information of the READ request is replaced with the WAY information in the index-coincident entry within the queue.

Control device for snoop tag

A transmission LSI calculates a buffer usage rate in accordance with data stored in a buffer in a transmission data processing unit and determines, in accordance with the calculated buffer usage rate, the number of signal lines that perform a phase readjustment and the timing thereof. Then, the transmission LSI and a receiving LSI perform a phase adjustment using some of the signal lines and continues a data transfer using the rest of the signal lines. Accordingly, it is possible to maintain the optimum phase of a clock without delaying the data transfer.

Data transfer unit, data transmission device, data receiving device, and control method

A northbridge, when detecting a synchronization break of a redundant CPU, stops the operation of an abnormal CPU bus where an error has occurred and the firmware in a firmware hub instructs the northbridge to inhibit an external instruction. In addition, the firmware saves the inside information of a normal CPU connected to a normal CPU bus and cache data on a memory and the northbridge issues reset to all CPUs in the home system board. The firmware then restores the inside information of the CPU saved on the memory to all CPUs and instructs the northbridge to cancel the inhibition of the external instruction.

Information processing apparatus for inhibiting instructions, saving and restoring internal information in response to abnormality in redundant processor system

A request issued by the CPU is output from the local arbiter by way of the CPU bus and the CPU-issued request queue. The cache replacement request loop-back circuit determines at the loop-back determination circuit whether the outputted request is a cache replacement request or not. A request other than a cache replacement request is output onto the local bus. A cache replacement request is output to the selector and sent to the request handling section when there is no valid request on the global bus.

Multiprocessor system, system board, and cache replacement request handling method

An information processing device having two processing units capable of operating in synchronization with each other, includes: a common unit capable of outputting an identical signal to the two processing units; detection units that are respectively provided for the processing units and each detects errors occurred in corresponding processing unit respectively; a comparison unit that compares outputs from the two processing units; and a control unit that controls signals from the processing units to the common unit, based on a detection result of the detection units and a comparison result of the comparison unit, and determines, if errors of an identical type are simultaneously detected by the detection units, that the errors are due to an error of the common unit.

Information processing device and error processing method

A control device managing a plurality of nodes transmitting and receiving data containing an error correcting code, comprises means accepting, when any one of the nodes detects an uncorrectable error from the data containing the error correcting code, a signal transmitted by the node detecting the error, means judging from a record of the detection of a first node, when accepting the signal from a second node receiving data transmitted by the first node, whether or not the first node has detected the uncorrectable error from the data transmitted to the second node, and means stopping, when the first node has detected the uncorrectable error from the data transmitted to the second node, a process attributed to the acceptance of the signal from the second node.

Node device, control device, control method and control program

In a system controller including a CPU-issued request queue having a circuit that processes plural requests having identical addresses not to be inputted to the CPU-issued request queue, a latest request other than a cache replace request is retained by an input-request retaining section. Consequently, even if an address of an issued request for cache replace request matches an address of a request retained by the CPU-issued request queue, the issued request for the cache replace request is not retried but is queued in the CPU-issued request queue when the address of the issued request for the cache replace request does not match the entire address retained by the input-request retaining section.

System controller, identical-address-request-queuing preventing method, and information processing apparatus having identical-address-request-queuing preventing function

In a multiprocessor system, a system controller includes snoop tags which are copy information on cache tags retained by respective CPUs. If the same address is registered in S (Shared state) in the cache tag of each of the CPUs connected to the same CPU bus, the address is registered in S (Shared state) in only any one of the snoop tags corresponding to the CPUs in which the same address is registered.

System controller, snoop tag modification method and information processing apparatus having snoop tag modification function

An information processing device of a multiprocessor configuration that can increase significantly the processing capability of read requests. The information processing device comprises a plurality of processing units, a plurality of cache memories for storing temporarily the data read by the plurality of processing units from respective main memories in combination with tag information indicating the state of the data that will be stored, and a system controller for controlling the access of the plurality of processing units to the main memories. The system controller comprises a tag copy unit for holding a copy of the tag information that will be stored in the cache memory, a plurality of write cues for storing write requests, and a store buffer for storing the arbitration results relating to a plurality of write requests that will be stored in the plurality of write cues.

Information processing device and data control method in information processing device

A multiprocessor system includes a judging unit judging whether a read command inputted to a global address crossbar is a read command to a memory on an own system board, an executing unit speculatively executing, when the judging unit judges that the read command is a read command to the memory on the own system board, the read command before global access based on an address notified from the global address crossbar, a setting unit setting for queuing data read from the memory in a data queue provided on a CPU without queuing the data in a data queue provided on the memory, and an instructing unit instructing, based on notification from the global address crossbar, the data queue provided on the CPU to discard the data or transmit the data to the CPU.

Multiprocessor system

A memory control device includes a writing unit writing information to a memory module, a reading unit reading the information from the memory module, an error detecting unit executing a detection of an error in the formation in parallel with the reading operation by the reading unit, an error correcting unit correcting the error in the information containing the error detected, and a control unit controlling a transfer and a receipt of the information to and from an external device and stopping, when the error is detected, an output of the information to the external device.

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Kawasaki, Japan

Daisuke Itou