# US 2014/0208030 A1 · Information processing apparatus and control method of information processing apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0208030 A1 - Document ID: US20140208030A1 - Status: Published application - Kind: A1 - Application number: 14/220,270 - Filed: 2014-03-20 - Published: 2014-07-24 - Earliest claimed: 2011-09-22 - Assignees: Fujitsu Limited - Applicants: Fujitsu Limited - Inventors: Hideki SAKATA; Go SUGIZAKI; Naoya ISHIMURA - Web page: https://patentgrep.com/patent/US20140208030A1 ## CPC - G06F 12/084: with a shared cache - G06F 12/0817: using directory methods - G06F 12/0811: with multilevel cache hierarchies - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract An information processing apparatus including a plurality of mutually connected system boards, wherein each of the system boards includes: a plurality of processors; and a plurality of memories each of which stores data and directory information corresponding to the data, and corresponds to any one of the processors, and wherein each of the plurality of processors, upon receiving a read request for data stored in a memory corresponding to the own processor from another processor, performs an exclusive logical sum operation on identification information included in the read request and identifying the another processor and a check bit included in the directory information and identifying a processor which holds target data of the read request, increments a count value included in the directory information and indicating the number of processors which hold the target data, and sets presence information included in the directory information and indicating a system board which includes the another processor. ## Claims ### Claim 1 An information processing apparatus comprising a plurality of mutually connected system boards, wherein each of the plurality of mutually connected system boards comprises: a plurality of processors; and a plurality of memories each of which stores data and directory information corresponding to the data, and corresponds to any one of the processors, and wherein each of the plurality of processors, upon receiving a read request for data stored in a memory corresponding to the own processor from another processor, performs an exclusive logical sum operation on identification information included in the read request and identifying the another processor and a check bit included in the directory information and identifying a processor which holds target data of the read request, increments a count value included in the directory information and indicating the number of processors which hold the target data, sets presence information included in the directory information and indicating a system board which includes the another processor, and outputs the target data to the another processor which has issued the read request. ### Claim 2 (depends on 1) The information processing apparatus according to claim 1, wherein each of the plurality of processors, upon receiving an acquisition request for an exclusive right for writing the data stored in the memory corresponding to the own processor from another processor, outputs an invalidation request for held data to all of the processors in a system board corresponding to the presence bit and, upon receiving input of an invalidation response of the held data from any one of the processors in the system board corresponding to the presence bit in response to the invalidation request, performs an exclusive logical sum operation on identification information of the processor which has made the invalidation response and the check bit, and decrements the count value. ### Claim 3 (depends on 2) The information processing apparatus according to claim 2, wherein the each of the plurality of processors, after receiving the acquisition request for the exclusive right for writing the data stored in the memory corresponding to the own processor from the another processor and updating the check bit and the count value and if the count value is other than 0, determines that any one of the processors included in the system board has broken down. ### Claim 4 (depends on 2) The information processing apparatus according to claim 2, wherein the each of the plurality of processors, after receiving the acquisition request for the exclusive right for writing the data stored in the memory corresponding to the own processor from the another processor and updating the check bit and the count value and if the count value is 1, determines that the processor corresponding to the check bit or the own processor has broken down. ### Claim 5 (depends on 2) The information processing apparatus according to claim 2, wherein the each of the plurality of processors, after receiving the acquisition request for the exclusive right for writing the data in the memory corresponding to the own processor from the another processor and updating the check bit and the count value and if the check bit is other than 0, determines that any one of the processors included in a system board corresponding to the own processor has broken down. ### Claim 6 (depends on 1) The information processing apparatus according to claim 1, wherein as the count value, bits except a least significant bit of a binary number indicating the number of processors which hold the data corresponding to the directory information are stored in the memory, and wherein the least significant bit of the binary number is calculated by performing an exclusive logical sum operation on all bits of the check bit. ### Claim 7 (depends on 1) The information processing apparatus according to claim 1, wherein when the identification information is expressed in binary number, the number of bits having a value of 1 is an odd number. ### Claim 8 A control method of an information processing apparatus comprising a plurality of mutually connected system boards comprising memories each of which stores data and directory information corresponding to the data, the control method, comprising: upon receiving a read request for data stored in a memory corresponding to the own processor from another processor, performing an exclusive logical sum operation on identification information included in the read request and identifying the another processor and a check bit included in the directory information and identifying a processor which holds target data of the read request; incrementing a count value included in the directory information and indicating the number of processors which hold the target data; setting presence information included in the directory information and indicating a system board which includes the another processor; and outputting the target data to the another processor.