Fujitsu Corporation

Go Sugizaki

Naoya Ishimura

Toshikazu Ueki

Hideyuki Koinuma

Akira Watanabe

Aiichiro Inoue

Shuji Yamamura

Seishi Okada

Tsuyoshi Motokurumada

Masahiro Mishima

Souta Kusachi

Satoshi Nakagawa

Naozumi Aoki

Shigekatsu Sagi

An arithmetic processing device has a first arithmetic processing unit including a first instruction controller that controls a write instruction to a memory and a first cache unit, and a second arithmetic processing unit including a second instruction controller and a second cache unit. The first arithmetic processing unit transmits an invalidation request to the second arithmetic processing unit when a write request to the memory is issued within a first transaction, and in response to the invalidation request, the second cache unit determines whether a second transaction is to be aborted based on information in the invalidation request when the second transaction conflicts with the first transaction for a cache block corresponding to a destination of the write request, and sends a determination result to the first arithmetic processing unit.

Arithmetic processing device, method of controlling arithmetic processing device, and information processing device

A central processing unit, connected to a main memory among a plurality of central processing units each including a cache memory, includes a control unit. The control unit executes a process including: classifying the plurality of central processing units into a smaller number than a total number of the plurality of central processing units, and writing to the main memory presence information indicating whether or not the same data as data stored in the main memory is held in a cache memory included in any of the central processing units that belong to a corresponding central processing unit group, for each central processing unit group of a plurality of central processing unit groups obtained by the classifying.

Central processing unit, method for controlling central processing unit, and information processing apparatus

An abnormality detection unit provided in at least one node among a plurality of nodes included in an information processing apparatus detects abnormality in a data transmission path of data transmission using a shared memory area sharable in a single node and other node, which is included in the storage unit provided in the single node or other nodes. An error information generation unit provided in the single node generates error information, based on the abnormality detected by the abnormality detection unit, and generates an interrupt with respect to a processor within a self node. The processor provided in the single node performs recovery processing, based on the error information according to the interrupt.

Information processing apparatus, computer-readable recording medium, and control method

An information processing apparatus includes a first arithmetic processing unit, a second arithmetic processing unit that is connected to a main storage, and a third arithmetic processing unit. The first arithmetic processing unit includes a cache memory that retains therein data. The second arithmetic processing unit includes a processing unit that notifies, when a read request for the data from the third arithmetic processing unit is not being executed when the replacement request is received, the first arithmetic processing unit of a completion notification indicating that the data has been written back to the main storage and the replacement process is completed and that notifies, when the read request is being executed when the replacement request is received, the first arithmetic processing unit of the completion notification after the read request has ended.

Information processing apparatus and control method of information processing apparatus

A processor includes a first transmitting unit that transmits, when receiving from a second processor a transmission request indicating transmission of target data which is read from a main storage unit and stored in the first processor, a transfer instruction to the first processor, the transfer instruction indicating transfer of the target data and state information to the second processor, the state information indicating a state of the target data used when the second processor reads and stores the target data. The processor includes a second transmitting unit that transmits acquisition information indicating acquisition of the target data to the second processor before receiving a response to the transfer instruction transmitted by the first transmitting unit from the first processor.

Processor and information processing apparatus

A system controller includes an output unit which transfers an access request from an access source coupled to the system controller to an other system controller; a local snoop control unit that determines whether a destination of the access request from the access source is a local memory unit coupled to the system controller, and locks the destination when the destination is the local memory unit; a receiving unit which receives the access request from the output unit and an access request from an other system controller; a global snoop control unit which sends a response indicating whether the access request is executable or not, and controls locking of the destination of the access request when the destination is the local memory unit; and an access processing unit which unlocks the locking and accesses the memory unit when the access request from the access source becomes executable.

System controller, information processing system, and access processing method

An information processing apparatus includes nodes having a first node and a second node each of which includes a processor and a memory in which at least a part of area is set as a shared memory area, and an interconnect that connects the nodes. The first node transmits communication data to be transmitted to the second node by attaching identification information used for accessing a memory in the second node. The second node determines whether or not an access to the shared memory area in the memory in the second node is permitted on the basis of the identification information that is attached to the communication data transmitted from the first node and identification information stored in a storing unit and used for controlling permission to access, from another node, the shared memory area in the memory in the second node.

Information processing apparatus and access control method

An information processing apparatus, a memory control method, and a memory control device are disclosed, the information processing apparatus including nodes each having a main memory, a processor including a cache memory, and a system controller. The system controller of at least one of the nodes includes a holding unit that holds address information corresponding to primary data stored in the main memory of its local node, and not cached in any of the cache memories of other nodes. The system controller of the at least one node may include local and global snoop control units, as well as a virtual tag expansion (VTAGx) unit, to maintain cache coherency, and under certain conditions, a snoop operation may be skipped or omitted.

Information processing apparatus, memory control method, and memory control device utilizing local and global snoop control units to maintain cache coherency

A system includes a first apparatus and a second apparatus connected via a transmission path. The first apparatus includes a transmitting unit that transmits a request as at least one packet and retransmits the at least one request packet if a time period between the request and a response is not less than a predetermined time period; and a receiving unit that receives the response as at least one response packet and discards any error packet and any redundant packet from among the received at least one response packet. The second apparatus includes: a receiving unit that receives the at least one request packet and discards any error packet from among the received at least one request packet; and a transmitting unit that determines a response type, selectively makes the at least one response packet redundant for any response of a specific type, and transmits the redundant response packets.

Transmitting system, apparatus, and method

A method of controlling an apparatus including a processor and an I/O controller includes storing execution information, receiving a first and a second requests successively, determining whether initiation of each execution of the first and the second requests is to be supervised by either of the processor and the I/O controller in reference to the execution information, transmitting the first request to the processor from the I/O controller, and upon completion of execution of the first request at the processor, transmitting the second request to the processor from the I/O controller when the initiations of executions of the first and second request is supervised by the I/O controller, and transmitting the first and second requests to the processor regardless of completion of execution of the first request by the processor when the initiations of executions of the first and second requests is supervised by the processor.

System having processor and I/O controller

One aspect of the embodiments utilizes an information processing apparatus having a plurality of system boards connected via a bus, each system board including a CPU having a cache memory, a main memory that forms a shared memory, and a system controller that manages the CPU and the main memory as well as controls a data transfer of at least one of the cache memory and the main memory by a memory access request, wherein each system controller including a snoop controller that selects a transfer source CPU from transfer source candidate CPUs each having cache memory including a data requested by the memory access request when the data is available in a plurality of cache memories.

Information processing apparatus and data transfer method

One aspect of the embodiments utilizes a system controller which has a broadcast transmitting and receiving unit that receives a memory access request from each of CPU and notifies to the other system controllers and a snoop control unit that judges when the memory access request from any of the CPUs for each of the cache memories in the CPU is received, whether object data conflicts with object data requested by a prior access request received earlier than the memory access request and whether the object data is present in any of the cache memories, selects the status of the cache memory of the CPU, notifies the other system controller of a snoop processing result in which the status selected and the cache memory are associated, and set a final status as the status of the system controller based on priority of each status of other system controllers.

Method and apparatus for setting status of cache memory

The present invention relates to an information processing apparatus equipped with a plurality of storage units and a plurality of system controllers sharing communication control on the plurality of storage units. For shortening the processing time needed for a memory access request, each of the plurality of system controllers includes a local snoop control unit for, when receiving the memory access request, retrieving target data on the memory access request from the storage unit, this system controller takes charge of, in parallel with transmission/reception processing on a retrieval instruction in a broadcast transmitting/receiving unit or processing in a global snoop control unit and a memory access control unit for fulfilling the memory access request when the target data is retrieved by the local snoop control unit and a predetermined condition reaches satisfaction.

Information processing apparatus, system controller, local snoop control method, and local snoop control program recorded computer-readable recording medium

A system controller, which executes a speculative fetch from a memory before determining whether data requested for a memory fetch request is in a cache by searching tag information of the cache, includes a consumption determining unit that monitors a consumption status of a hardware resource used in the speculative fetch, and determines whether a consumption of the hardware resource exceeds a predetermined value; and a speculative-fetch issuing unit that stops issuing the speculative fetch when the consumption determining unit determines that the consumption of the hardware resource exceeds the predetermined value.

System controller, speculative fetching method, and information processing apparatus

A system control apparatus and method capable of increasing the possibility of recovery from a synchronization error in snooping between system controllers are provided. The system control apparatus has a local port that holds a memory access request received externally and reoutputs it in response to an error retry instruction. A broadcast output section broadcasts the memory access request. A broadcast input section receives the broadcast memory access request. A global port holds the received memory access request. A snoop control section transmits and receives cache status information containing a result of snooping, and detects a synchronization error on the basis of the cache status information. If a synchronization error occurs, the snoop control section outputs the error retry instruction to the local port holding the memory access request that resulted in the synchronization error.

Growing community of inventors

Kawasaki, Japan

Go Sugizaki