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公开(公告)号:US11169956B2
公开(公告)日:2021-11-09
申请号:US16831590
申请日:2020-03-26
Applicant: Graphcore Limited
Inventor: Simon Knowles , Ola Torudbakken , Stephen Felix , Lars Paul Huse
Abstract: One aspect of the invention provides a computer comprising a plurality of interconnected processing nodes arranged in a ladder configuration comprising a plurality of facing pairs of processing nodes. The processing nodes of each pair are connected to each other by two links. A processing node in each pair is connected to a corresponding processing node in an adjacent pair by at least one link. The processing nodes are programmed to operate the ladder configuration to transmit data around two embedded one-dimensional rings formed by respective sets of processing nodes and links, each ring using all processing nodes in the ladder once only.
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公开(公告)号:US11119873B2
公开(公告)日:2021-09-14
申请号:US16395363
申请日:2019-04-26
Applicant: Graphcore Limited
Inventor: Stephen Felix
IPC: G06F11/20
Abstract: A processor comprises a plurality of processing units, wherein there is a fixed transmission time for transmitting a message from a sending processing unit to a receiving processing unit, based on the physical positions of the sending and receiving processing units in the processor. The processing units are arranged in a column, and the fixed transmission time depends on the position of a processing circuit in the column. An exchange fabric is provided for exchanging messages between sending and receiving processing units, the columns being arranged with respect to the exchange fabric such that the fixed transmission time depends on the distances of the processing circuits with respect to the exchange fabric. The processor comprises at least one delay stage for each processing circuit and switching circuitry for selectively switching the delay stage into or out of a communication path involved in message exchange. For processing circuits up to a defective processing circuit in the column, the delay stage is switched into the communication path, and for processing circuits above the defective processing circuit in the column, including a repairing processing circuit which repairs the defective processing circuit the delay stage is switched out of the communication path whereby the fixed transmission time of processing circuits is preserved in the event of a repair of the column.
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公开(公告)号:US20210271527A1
公开(公告)日:2021-09-02
申请号:US17320904
申请日:2021-05-14
Applicant: Graphcore Limited
Inventor: Daniel John Pelham Wilkinson , Simon Christian Knowles , Matthew David Fyles , Alan Graham Alexander , Stephen Felix
Abstract: A processing system comprising an arrangement of tiles and an interconnect between the tiles. The interconnect comprises synchronization logic for coordinating a barrier synchronization to be performed between a group of the tiles. The instruction set comprises a synchronization instruction taking an operand which selects one of a plurality of available modes each specifying a different membership of the group. Execution of the synchronization instruction cause a synchronization request to be transmitted from the respective tile to the synchronization logic, and instruction issue to be suspended on the respective tile pending a synchronization acknowledgement being received back from the synchronization logic. In response to receiving the synchronization request from all the tiles in the group as specified by the operand of the synchronization instruction, the synchronization logic returns the synchronization acknowledgment to the tiles in the specified group.
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24.
公开(公告)号:US11036673B2
公开(公告)日:2021-06-15
申请号:US16419276
申请日:2019-05-22
Applicant: Graphcore Limited
Inventor: Stephen Felix , Jonathan Mangnall
IPC: G06F15/80
Abstract: A method of recording tile identifiers in each of a plurality of tiles of a multitile processor is described. Tiles are arranged in columns, each column having a plurality of processing circuits, each processing circuit comprising one or more tiles, wherein a base processing circuit in each column is connected to a set of processing circuit identifier wires. A base value is generated on each of the set of processing circuit identifier wires for the base processing circuit in each column. At the base processing circuit, the base value on the set of processing circuit identifier wires is read and incremented by one. The incremented value is propagated to a next processing circuit in the column, and at the next processing circuit a unique identifier is recorded by concatenating an identifier of the column and the incremented value.
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公开(公告)号:US11023413B2
公开(公告)日:2021-06-01
申请号:US16725313
申请日:2019-12-23
Applicant: Graphcore Limited
Inventor: Daniel John Pelham Wilkinson , Stephen Felix , Richard Luke Southwell Osborne , Simon Christian Knowles , Alan Graham Alexander , Ian James Quinn
IPC: G06F15/80 , G06F9/52 , G06F15/173
Abstract: A method of operating a system comprising multiple processor tiles divided into a plurality of domains wherein within each domain the tiles are connected to one another via a respective instance of a time-deterministic interconnect and between domains the tiles are connected to one another via a non-time-deterministic interconnect. The method comprises: performing a compute stage, then performing a respective internal barrier synchronization within each domain, then performing an internal exchange phase within each domain, then performing an external barrier synchronization to synchronize between different domains, then performing an external exchange phase between the domains.
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公开(公告)号:US20200293278A1
公开(公告)日:2020-09-17
申请号:US16395502
申请日:2019-04-26
Applicant: Graphcore Limited
Inventor: Jonathan Mangnall , Stephen Felix
Abstract: An execution unit for a processor, the execution unit comprising: a look up table having a plurality of entries, each of the plurality of entries comprising an initial estimate for a result of an operation; a preparatory circuit configured to search the look up table using an index value dependent upon the operand to locate an entry comprising a first initial estimate for a result of the operation; a plurality of processing circuits comprising at least one multiplier circuit; and control circuitry configured to provide the first initial estimate to the at least one multiplier circuit of the plurality of processing circuits so as perform processing, by the plurality of processing units, of the first initial estimate to generate the function result, said processing comprising applying one or more Newton Raphson iterations to the first initial estimate.
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公开(公告)号:US20190155768A1
公开(公告)日:2019-05-23
申请号:US16165607
申请日:2018-10-19
Applicant: Graphcore Limited
Inventor: Daniel John Pelham Wilkinson , Richard Luke Southwell Osborne , Stephen Felix , Graham Bernard Cunningham , Alan Graham Alexander
Abstract: A processor comprising multiple tiles on the same chip, and an external interconnect for communicating data off-chip in the form of packets. The external interconnect comprises an external exchange block configured to provide flow control and queuing of the packets. One of the tiles is nominated by the compiler to send an external exchange request message to the exchange block on behalf of others with data to send externally. The exchange sends an exchange-on message to a first of these tiles, to cause the first tile to start sending packets via the external interconnect. Then, once this tile has sent its last data packet, the exchange block sends an exchange-off control packet to this tile to cause it to stop sending packets, and sends another exchange-on message to the next tile with data to send, and so forth.
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公开(公告)号:US20190121679A1
公开(公告)日:2019-04-25
申请号:US15885972
申请日:2018-02-01
Applicant: Graphcore Limited
Inventor: Daniel John Pelham Wilkinson , Simon Christian Knowles , Matthew David Fyles , Alan Graham Alexander , Stephen Felix
Abstract: A processing system comprising an arrangement of tiles and an interconnect between the tiles. The interconnect comprises synchronization logic for coordinating a barrier synchronization to be performed between a group of the tiles. The instruction set comprises a synchronization instruction taking an operand which selects one of a plurality of available modes each specifying a different membership of the group. Execution of the synchronization instruction cause a synchronization request to be transmitted from the respective tile to the synchronization logic, and instruction issue to be suspended on the respective tile pending a synchronization acknowledgement being received back from the synchronization logic. In response to receiving the synchronization request from all the tiles in the group as specified by the operand of the synchronization instruction, the synchronization logic returns the synchronization acknowledgment to the tiles in the specified group.
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公开(公告)号:US20190121388A1
公开(公告)日:2019-04-25
申请号:US15886053
申请日:2018-02-01
Applicant: Graphcore Limited
Inventor: Simon Christian Knowles , Daniel John Pelham Wilkinson , Richard Luke Southwell Osborne , Alan Graham Alexander , Stephen Felix , Jonathan Mangnall , David Lacey
Abstract: The invention relates to a computer implemented method of generating multiple programs to deliver a computerised function, each program to be executed in a processing unit of a computer comprising a plurality of processing units each having instruction storage for holding a local program, an execution unit for executing the local program and data storage for holding data, a switching fabric connected to an output interface of each processing unit and connectable to an input interface of each processing unit by switching circuitry controllable by each processing unit, and a synchronisation module operable to generate a synchronisation signal, the method comprising: generating a local program for each processing unit comprising a sequence of executable instructions; determining for each processing unit a relative time of execution of instructions of each local program whereby a local program allocated to one processing unit is scheduled to execute with a predetermined delay relative to a synchronisation signal a send instruction to transmit at least one data packet at a predetermined transmit time, relative to the synchronisation signal, destined for a recipient processing unit but having no destination identifier, and a local program allocated to the recipient processing unit is scheduled to execute at a predetermined switch time a switch control instruction to control the switching circuitry to connect its processing unit wire to the switching fabric to receive the data packet at a receive time.
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公开(公告)号:US11928523B2
公开(公告)日:2024-03-12
申请号:US17446681
申请日:2021-09-01
Applicant: Graphcore Limited
Inventor: Simon Knowles , Daniel John Pelham Wilkinson , Alan Alexander , Stephen Felix , Richard Osborne , David Lacey , Lars Paul Huse
CPC classification number: G06F9/522 , G06F9/30087 , G06F9/3858 , G06F1/12
Abstract: A multi-tile processing unit in which the tiles in the processing unit may be divided between two or more different external sync groups for performing barrier synchronisations. In this way, different sets of tiles of the same processing unit each sync with different sets of tiles external to that processing unit.
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