JP5022330B2 - Request issuing node, request receiving node, system, and control method - Google Patents

Description

  The present invention relates to a request issuing node, a request receiving node, a system, and a control method, and more particularly, to a request issuing node, a request receiving node, a system, and a control method that perform request arbitration.

  In an information processing system or the like, a request is transmitted between nodes and a reply is returned according to the request. When receiving a request from the request issuing node, the request receiving node stores the request in the reception buffer. After the predetermined processing is completed, the reply is sent to the request issuing node, but at that time, the reception buffer is not released yet, the predetermined processing is completed at the request issuing node that has received the reply, and the request is issued from the request issuing node. When an instruction is sent, the reception buffer is released.

  An example of a technique related to request arbitration related to transmission / reception of such a request is disclosed in Patent Documents 1 and 2.

JP 2003-122706 A JP-A-1-269149

  However, the following problems occur in relation to the arbitration when the request transmission from the request issuing node and the request release instruction transmission conflict.

  That is, when the reception buffer of the request receiving node is busy, the request receiving node transmits a retry request to the request issuing node. In response to this, the request issuing node issues the request again. At this time, if the request issuing node competes with the request receiving node for transmission of the request and the request release instruction, the request issuing node always performs arbitration so that the request transmission is prioritized. In this way, since the retransmission of the request is prioritized and the transmission of the request release instruction is delayed, the reception buffer of the request receiving node is not released, and as a result, the retry operation occurs again. As a result, the number of retries will increase.

  As described above, when arbitration is always performed with a priority of “request transmission priority> request release instruction transmission priority”, the number of retries increases and traffic increases. Conversely, if the priority is always “request transmission priority <request release instruction transmission priority”, the delay in request transmission timing increases. As described above, in any case, there is a problem that the system performance is deteriorated.

  An object of the present invention is to provide a request issuing node, a request receiving node, a system, and a control method that solve the above-described problem of deterioration in system performance.

  The request issuing node of the present invention includes a request transmitting means for transmitting a request to the request receiving node, and a request for releasing a request storage location in the request receiving node storing the request when a reply to the request is received from the request receiving node. Request release instruction transmission means for transmitting a release instruction to a request receiving node, and transmission of a request and request release instruction when all of a predetermined number of request storage locations in the request receiving node are in use. Arbitration means for switching the priority transmission from request transmission to request release instruction transmission when there is a conflict.

  The request receiving node of the present invention has a plurality of request storage locations for storing the requests received from the request issuing node, transmits a reply to the request to the request issuing node, and issues a request release instruction corresponding to the reply from the request issuing node. When a request is received, a busy notification is generated when the request receiving storage means for releasing the request storing place where the corresponding request is stored and a predetermined number of request storing places in the request receiving storage means are in use. Busy notification generating means.

  The system of the present invention includes a request issuing node and a request receiving node. The request issuing node receives a request when a request transmitting means for transmitting a request to the request receiving node and a reply to the request are received from the request receiving node. Request release instruction sending means for sending a request release instruction to release the request storage location in the stored request receiving node to the request receiving node, and all of the predetermined number of request storage locations in the request receiving node are in use In this case, when request transmission and request release instruction transmission compete, arbitration means for switching the priority transmission from request transmission to request release instruction transmission, the request receiving node receives from the request issuing node. If there are multiple request storage locations for storing the requested request, a reply to the request is sent to the request issuing node, and a request release instruction corresponding to the reply is received from the request issuing node, the request storage storing the corresponding request Request reception storage means for releasing the location, and busy notification generation means for generating a busy notification when a predetermined number of request storage locations in the request reception storage means are in use.

  The request issuing node control method of the present invention transmits a request to a request receiving node, and when receiving a reply to the request from the request receiving node, a request release instruction for releasing the request storage location in the request receiving node storing the request. Is sent to the request receiving node, and when all of the predetermined number of request storage locations in the request receiving node are in use, when the request transmission and the request release instruction transmission compete, Switch from sending a request to sending a request release instruction.

  The request receiving node control method of the present invention stores a request received from a request issuing node in a request storage location, transmits a reply to the request to the request issuing node, and receives a request release instruction corresponding to the reply from the request issuing node. In this case, the request storage location where the corresponding request is stored is released, and a busy notification is generated when a predetermined number of request storage locations in the request reception storage means are in use.

  In the system control method of the present invention, when a request issuing node transmits a request to a request receiving node and receives a reply to the request from the request receiving node, the request storage location in the request receiving node storing the request is released. When the request release instruction is sent to the request receiving node and all of the predetermined number of request storage locations in the request receiving node are in use, the priority is given to the transmission of the request and the request release instruction. The request receiving node stores the request received from the request issuing node in the request storage location, and sends a reply to the request to the request issuing node. When a request release instruction corresponding to a reply is received from a row node, the request storage location where the corresponding request is stored is released, and a predetermined number of request storage locations in the request reception storage means are in use Generate busy notifications.

  The present invention has an effect that the system performance can be improved.

  First, an example of a general request arbitration system assumed by the present invention will be described.

  FIG. 1 is a diagram showing a configuration of the request arbitration system 001. The request arbitration system 001 includes nodes 101 to 103 connected to each other. The nodes 101 to 103 include processors 104 to 106, memory controllers 107 to 109, and node controllers 110 to 112, respectively. FIG. 2 is a diagram illustrating an internal configuration of the node controllers 110 to 112. For example, the node controller 110 includes a request issuing unit 201, a request receiving unit 202, and an interface control unit 203.

  Next, the operation will be described. FIG. 3 is a diagram for explaining the operation of the request arbitration system 001. Here, a case where the node 101 is a request issuing node and the node 102 is a request receiving node will be described. For this reason, the request issuing unit 201 will be described with respect to the node controller 110, and the request receiving unit 309 will be described with respect to the node controller 111.

  First, the processor 104 transmits a request to the request queue 303 in the request issuing unit 201. The request is transmitted from the request queue 303 through the arbitration circuit 304 to the other node from the interface control unit 203. Here, it is assumed that a request from the node 101 is transmitted to the node 102 using the wiring 306. The request reception buffer 305 in the request reception unit 309 of the node 102 stores the received request.

  The request reception buffer 305 transmits the request to the memory controller 108. Then, the memory controller 108 transmits a reply to the request to the request reception buffer 305. At this time, the request output to the memory controller 108 remains in the request reception buffer 305, and even if a reply is returned, the request entry is not released. The request entry is a place for storing the request in the buffer. For example, when there are 32 request entries, the request reception buffer 305 can store a maximum of 32 requests. When a request entry is released, the request reception buffer 305 stores a new request in the request entry.

  When receiving a reply from the memory controller 108 as described above, the request reception buffer 305 transmits the reply to the node 101 via the interface control unit 204 and the wiring 307. The reply received by the node 101 is sent to the reply queue 301 via the interface control unit 203, and the reply queue 301 transmits the received reply to the processor 104. At the same time as a reply is sent to the processor 104, a request release instruction corresponding to the reply sent to the processor 104 is sent to the request release instruction queue 302. This request release instruction is an instruction to release a request entry in the request reception buffer 305 in which a request corresponding to the received reply is stored.

  The request release instruction queue 302 transmits a request release instruction to the request reception buffer 305 via the arbitration circuit 304 and the wiring 306. The request reception buffer 305 releases the corresponding request entry. Thus, one request process is completed.

  As described above, even if the request reception buffer 305 receives a reply from the memory controller 108, the request reception buffer 305 does not yet release the request entry at that stage. Thereafter, when the reply is returned to the processor 104 and the request reception buffer 305 receives the request release instruction, the request reception buffer 305 releases the request entry. The above is the basic operation.

  In the system as described above, when the request reception buffer 305 is busy (all request entries are in an open state) and a request cannot be received, the request reception buffer 305 transmits a retry request to the request issuing unit 201. The request queue 303 issues the same request as the request that could not be received by the request reception buffer 305, and transmits it to the node 102 via the arbitration circuit 304. The request queue 303 issues a request every time a retry request is received from the request reception buffer 305. The request reception buffer 305 issues a retry request every time a request is received in a state where there is no space.

  As described above, when arbitration is always performed with the priority of “request transmission priority> request release instruction transmission priority”, the number of retries increases and traffic increases. Conversely, if the priority is always “request transmission priority <request release instruction transmission priority”, the request delay increases. Thus, in any case, there is a problem that the system performance is deteriorated.

  Next, an outline of the present invention for solving this problem will be described.

  FIG. 4 is a diagram showing a configuration of the request arbitration system 001.

  The request arbitration system 001 includes a request issue node 500 and a request reception node 600.

  The request issue node 500 includes a request queue 303, a request release instruction queue 302, and an arbitration circuit 304.

  The request queue 303 is a request transmission unit that transmits a request to the request reception node 600.

  When the request release instruction queue 302 receives a reply to the request from the request reception node 600, the request release instruction queue 302 issues a request release instruction to release the request entry (request storage location) of the request reception buffer 305 of the request reception node 600 corresponding to the request. Request release instruction transmission means for transmitting to the request receiving node 600.

  The arbitration circuit 304 is a circuit that arbitrates transmission of a request and transmission of a request release instruction. When the request reception buffer 305 is busy (when all of the predetermined number of request entries are in use), a request for priority transmission is requested when the request transmission and the request release instruction transmission compete. Arbitration means for switching from transmission of request to transmission of request release instruction.

  The request reception node 600 includes a request reception buffer 305 and a busy notification generation unit 602.

  The request reception buffer 305 has a plurality of request entries (request storage locations) for storing requests received from the request issuing node 500, transmits a reply to the request to the request issuing node 500, and responds to the reply from the request issuing node 500. When the request release instruction is received, the request reception storage means releases the request entry in which the corresponding request is stored.

  The busy notification generation unit 602 is a busy notification generation unit that generates a busy notification when a predetermined number of request entries in the request reception buffer 305 are in use.

  As described above, the present invention has an effect that the system performance can be improved.

  The reason is that transmission of a request release instruction is prioritized when the request reception buffer 305 is busy. As a result, the number of retries can be reduced, and traffic can be reduced.

  The present invention has an effect that the latency of a request can be shortened even when the request release instruction and the request conflict.

  The reason is that priority is given to the transmission of the request in normal times such as before the request reception buffer 305 becomes busy.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. The part added to the request arbitration system 001 which is the premise of the present invention described with reference to FIGS. 1, 2, and 3 will be described in detail.

  FIG. 5 is a diagram showing a configuration of the request issuing unit 201 in the embodiment of the present invention. Although the request issuing unit 201 in the node 101 will be described here, the request issuing units in other nodes such as the node 102 have the same configuration.

  The request issuing unit 201 includes a reply queue 301, a request release instruction queue 302, a request queue 303, an arbitration circuit 304, and a switching controller 401.

  The reply queue 301 receives a reply to be sent to the processor 104 from another node (the node 102 will be described below as an example).

  The request queue 303 receives a request from the processor 104 and transmits it to the node 102.

  The request release instruction queue 302 receives a request release instruction corresponding to the reply, and transmits a request release instruction for releasing the request entry in the request reception buffer 305 of the node 102 to the node 102.

  The arbitration circuit 304 performs arbitration between request transmission and request release instruction transmission. In this embodiment, instead of always giving priority to request transmission, the arbitration circuit 304 switches the priority transmission from request transmission to request release instruction transmission when the request reception buffer 305 is busy. .

  The switching controller 401 is a switching unit that transmits a switching signal that prioritizes transmission of a request release instruction to the arbitration circuit 304 when a busy notification packet is received from the node 102. The switching controller 401 stops transmission of a switching signal that gives priority to the arbitration circuit 304 to transmit a request release instruction when a predetermined time has elapsed after receiving the busy notification packet.

  FIG. 6 is a diagram illustrating a configuration of the switching controller 401.

  The switching controller 401 includes a timer 406, a setting register 407, and a switching signal generation circuit 408.

  When the timer 406 receives a busy notification packet from the node 102, the timer 406 starts counting up from the initial value.

  The setting register 407 stores a predetermined value.

  When the switching signal generation circuit 408 receives a busy notification packet from the node 102, the switching signal generation circuit 408 generates a switching signal that gives priority to the arbitration circuit 304 to transmit a request release instruction. In response, the arbitration circuit 304 switches the arbitration priority from “request transmission priority> request release instruction transmission priority” to “request transmission priority <request release instruction transmission priority”. The switching signal generation circuit 408 stops the generation of the switching signal when the timer 406 reaches a predetermined value (when it becomes the same as the value of the setting register 407). In response to this, the priority of the arbitration circuit 304 returns to “request transmission priority> request release instruction transmission priority”.

  FIG. 7 is a diagram showing a configuration of the request receiving unit 309 in the present embodiment. Although the request receiving unit 309 in the node 102 will be described here, the request receiving units in other nodes such as the node 101 have the same configuration. The request receiving unit 309 receives a request and a request release instruction, and transmits a retry request, a reply, and a busy notification packet via the interface control unit 204. When the buffer 305 is busy, the interface control unit 204 broadcasts a busy notification packet to the request issuing units of all nodes such as the request issuing unit 201 of the node 101 and the request issuing unit 308 of the node 102. All the switching controllers such as the switching controller 401 of the request issuing unit 201 and the switching controller (not shown) of the request issuing unit 308 receive the busy notification packet.

  The request reception unit 309 includes a request reception buffer 305 and a busy notification packet generation unit 402.

  The request reception buffer 305 receives a request, a reply, and a request release instruction. The request reception buffer 305 stores the request received from the node 101 in the request entry, and transmits a reply to the request to the node 101. When a request release instruction is received from the node 101, the request entry is released.

  When the request reception buffer 305 becomes busy, the busy notification packet generation unit 402 generates a busy notification packet and transmits it to all the nodes including the node 101. Specifically, the busy notification packet generation unit 402 counts the number of valid request entries stored in the request reception buffer 305 and determines whether or not the set threshold value is exceeded.

  FIG. 8 is a diagram illustrating a configuration of the busy notification packet generation unit 402.

  The busy notification packet generation unit 402 includes a valid request measurement counter 403, a threshold register 404, and a busy notification packet generation circuit 405.

  The valid request measurement counter 403 increases (increments) the count value by 1 every time a request is received from another node such as the node 101, and decreases the count value by 1 each time a request release instruction is received (decrement). To do). Note that nothing is done when retrying.

  The threshold register 404 stores a predetermined value.

  When the value of the valid request measurement counter 403 becomes equal to or greater than a predetermined value stored in the threshold register 404, the busy notification packet generation circuit 405 generates a busy notification packet and transmits it to other nodes such as the node 101. The busy notification packet generation circuit 405 includes a comparator 410, a register 411, an AND circuit 412, and a packet generation circuit 413.

  The comparator 410 outputs 0 when the value of the valid request measurement counter 403 is smaller than the predetermined value stored in the threshold register 404, and 1 when the value of the valid request measurement counter 403 is equal to or larger than the predetermined value. Output.

  The register 411 holds the value output from the comparator 410, and outputs the held value after a predetermined period (for example, after one clock).

  The AND circuit 412 takes a logical product of a value output from the comparator 410 and a value obtained by inverting the value output from the register 411, and outputs the value of the logical product.

  The packet generation circuit 413 generates a busy notification packet when the logical product value is 1.

  FIG. 9 is a diagram for explaining the operation of the busy notification packet generation circuit 405.

  When the value of the threshold register 404 is larger than the value of the valid request measurement counter 403, the output value of the comparator 410 is 0, and this is stored in the register 411 at the clock timing immediately thereafter. Further, 0 which is the value of the register 411 is output at the next clock, and this is given to the inverting input terminal of the AND circuit 412. The input values of the inverting input terminal and the non-inverting input terminal of the AND circuit 412 are 0 and 0, respectively, and the output value of the AND circuit 412 is 0 (a). Next, when the value of the valid request measurement counter 403 becomes equal to or larger than the value of the threshold register 404, the output value of the comparator 410 becomes 1, and is stored in the register 411 at the clock timing immediately after that. At this time, since 0 is still output from the register 411, the input values of the inverting input terminal and the non-inverting input terminal of the AND circuit 412 are 0 and 1, respectively, and the output value of the AND circuit 412 is 1 ( A pulse is generated) (b). At the next clock timing, 1 stored one clock before is output from the register 411, the input values of the inverting input terminal and the non-inverting input terminal of the AND circuit 412 are 1 and 1, respectively, and the AND circuit 412 sets 0 again. Output (c).

  Next, the operation of the embodiment of the present invention will be described with reference to the drawings. First, the operation of the entire request arbitration system 001 will be described.

  FIG. 10 is a sequence diagram showing an outline of the operation of the request arbitration system 001.

  The node 101 (referred to as a request issuing node) transmits a request to the node 102 (referred to as a request receiving node) (A1). In response to this, the node 102 stores the received request in the request entry of the reception buffer (B1), and transmits a reply (B2). At this time, when the reception buffer becomes busy due to the reception of the request (B3, Y), the node 102 generates a busy notification packet and transmits it to other nodes including the node 101 (B4).

  When the node 101 receives the reply (A2), it transmits a request release instruction. Here, when the node 101 is not trying to transmit a new request, there is no contention between the request transmission and the request release instruction transmission (A3, N), and the node 101 transmits the request release instruction (A4). . When the node 101 is about to transmit a new request, a conflict between request transmission and request release instruction transmission occurs (A3, Y). In this case, the node 101 determines whether a busy notification packet has been received (A5). If the busy notification packet has not been received (A5, N), the request transmission is prioritized (A9) and the request is transmitted. (A1).

  When the busy notification has been received (A5, Y), the node 101 prioritizes transmission of the request release instruction (A6) and transmits the request release instruction to the node 102 (A7). In response to this, the node 102 releases the corresponding request entry (B5).

  When a predetermined time has elapsed (A8, Y), the node 101 switches to give priority to request transmission again (A9).

  Next, the operation of the busy notification packet generator 402 will be described. FIG. 11 is a flowchart showing the operation of the busy notification packet generation unit 402. This corresponds to the processing of B3 and B4 in FIG.

  The request reception buffer 305 increments each time a request is received from another node such as the node 101 and decrements each time a request release instruction is received from another node, thereby measuring the valid request in the busy notification packet generation unit 402. The counter 403 counts valid requests (C1). Then, the comparator 410 determines whether the number of valid requests is greater than or equal to a predetermined threshold value. That is, the values of the valid request measurement counter 403 and the threshold register 404 are compared (C2). As a result of the comparison, when the value of the valid request measurement counter 403 is smaller than the value of the threshold register 404 (C2, No), the busy notification packet generation unit 402 does not generate a busy notification packet, and the process returns to C1, and the request And request release instructions.

  The busy notification packet generation unit 402 generates and transmits a busy notification when the number of valid requests at the previous count is smaller than a predetermined threshold and the number of valid requests at the current count is equal to or greater than the predetermined threshold (C3). (C4). Specifically, the busy notification packet generation unit 402 generates a busy notification packet when the value of the valid request measurement counter 403 is equal to or greater than the value of the threshold register 404 (C4). For example, when the number of request entries is 32 and the value of the threshold register 404 is 30, the busy notification packet generation unit 402 generates a busy notification packet when the value of the valid request measurement counter 403 becomes 30 or more.

  When the number of previous and current valid requests is equal to or greater than a predetermined threshold, or when a busy notification is generated and transmitted in the process of C4, the process returns to the process of counting the number of valid requests (C1). As described above, when the value of the previous valid request measurement counter 403 is equal to or greater than the value of the threshold register 404, and this time is also equal to or greater than the value of the threshold register 404, the busy notification packet has already been generated. No notification packet is generated.

  Next, the operation of the switching controller 401 that has received the generation and transmission of the busy notification packet will be described.

  FIG. 12 is a flowchart for explaining the operation of the switching controller 401. This corresponds to the processing of A5 and A6 in FIG.

  First, the switching controller 401 determines whether a busy notification packet has been received (D1). When receiving the busy notification packet (D1, Yes), the switching controller 401 sets the timer value to 1 (D2). When the busy notification packet is not received (D1, No), it is determined whether the timer value is the same as the threshold value, the timer value is 0, or the timer value is greater than 0 and smaller than the threshold value (D3).

  If the timer value is the same as the predetermined threshold, the timer value is reset to 0 (D4). When the timer value is larger than 0 and smaller than the predetermined threshold value, 1 is added to the timer value (D5).

  When the timer value is set to 1 (D2), when the timer value is reset to 0 (D4), when the busy notification packet is not received and the timer value is 0, or 1 is added to the timer value (D5), it is determined whether the timer value is greater than 0 (D6).

  When the timer value is greater than 0 (D6, Yes), the value of the switching signal that determines which of request transmission and request release instruction transmission is given priority is set to 1 that gives priority to the request release instruction (D7). When the timer value is 0 (when the timer value is not greater than 0 (D6, No)), the value of the switching signal is set to 0 which gives priority to the request (D8).

  Next, FIG. 12 will be described more specifically. First, the switching controller 401 monitors whether a busy notification packet is received (D1). When the busy notification packet has not been received (D1, No), the timer value is determined (D3). Next, it is determined whether or not the timer value is greater than 0 (D6). Since the timer value is 0 and the timer value is not greater than 0 (D6, No), a switching signal is not generated under the switching signal generation condition (request priority). (D8) The busy notification packet reception is monitored again (D1).

  Next, the switching controller 401 monitors the reception of the busy notification packet (D1), and when the busy notification packet is received for the first time (D1, Yes), sets the timer value to 1 (D2). The switching signal generation condition (whether the timer value is greater than 0) is determined (D6). Since the timer value is greater than 0 (D6, Yes), the switching signal is generated (D7), so the arbitration circuit 304 releases the request. Switch to instruction transmission priority arbitration. As described above, when the busy notification packet is received in the initial state, priority is given to the transmission of the request release instruction.

  When returning to step D1 in the state of switching to the request release instruction priority arbitration, if a new busy notification packet has not been received (D1, No), the processing is changed according to the timer value (D3).

  First, when the timer value is equal to the threshold value set by the setting register 407, the switching controller 401 resets the timer value and sets the value to 0 (D4). Next, when the reset is performed, the switching signal generation condition (whether the timer value is greater than 0) is determined (D6). Since the timer value is not greater than 0 (D6, No), the switching signal is not generated (D8). The arbitration circuit 304 switches to request priority arbitration. That is, when a predetermined time elapses after receiving the busy notification packet, the request transmission is given priority.

  When the timer value is larger than 0 and the timer value is smaller than the threshold value, the switching controller 401 counts up the timer value (D5). The switching signal generation condition (whether the timer value is greater than 0) is determined (D6). Since the timer value is greater than 0 (D6, Yes), the switching signal is generated (D7), so the arbitration circuit 304 releases the request. Instruction priority arbitration remains. That is, when a predetermined time has not elapsed since the busy notification packet was received, the state where priority is given to the transmission of the request release instruction continues.

  When a busy notification packet is received and a new busy notification packet is received before the timer value becomes equal to the threshold value (D1, Yes), the timer value is set to 1 (D2). The switching signal generation condition (whether the timer value is greater than 0) is determined (D6). Since the timer value is greater than 0 (D6, Yes), the switching signal is generated, and the arbitration circuit 304 remains in the request release instruction priority arbitration. become. That is, even when the predetermined time has not elapsed since the busy notification packet was received, the timer 406 is reset when the busy notification packet is received again, and priority is given to the transmission of the request release instruction until the predetermined time has elapsed from this point. The state will continue.

  The above-described embodiment has an effect that the system performance can be improved.

  The reason is that transmission of a request release instruction is prioritized when the request reception buffer 305 is busy. As a result, the number of retries can be reduced and traffic can be reduced.

  Furthermore, this embodiment has an effect that the latency of the request can be shortened even when the request release instruction and the request conflict.

  The reason is to prioritize request transmission before the request reception buffer 305 is busy and when a predetermined time has elapsed after the request reception buffer 305 is busy. In other words, it is because priority is given to the transmission of requests during normal times.

It is a figure which shows the structure of the request arbitration system 001. It is a figure which shows the internal structure of the node controllers 110-112. It is a figure for demonstrating operation | movement of the request arbitration system. It is a figure which shows the structure of the request arbitration system 001. It is a figure which shows the structure of the request issuing part 201 in embodiment of this invention. 2 is a diagram illustrating a configuration of a switching controller 401. FIG. It is the figure which showed the structure of the request reception part 309 in this Embodiment. 6 is a diagram showing a configuration of a busy notification packet generation unit 402. FIG. 6 is a diagram for explaining the operation of a busy notification packet generation circuit 405. FIG. It is the sequence diagram which showed the outline | summary of operation | movement of the request arbitration system 001. 5 is a flowchart showing an operation of a busy notification packet generator 402. 4 is a flowchart illustrating an operation of a switching controller 401.

Explanation of symbols

001 Request arbitration system 101, 102, 103 Nodes 104, 105, 106 Processors 107, 108, 109 Memory controller 110, 111, 112 Node controller 201 Request issuing unit 202 Request receiving unit 203 Interface control unit 204 Interface control unit 301 Reply queue 302 Request release instruction queue 303 Request queue 304 Arbitration circuit 305 Request reception buffer 306, 307 Wiring 308 Request issue unit 309 Request reception unit 401 Switching controller 402 Busy notification packet generation unit 403 Valid request measurement counter 404 Threshold register 405 Busy notification packet generation circuit 406 Timer 407 Setting register 408 Switching signal generation Circuit 410 Comparator 411 Register 412 AND circuit 413 Packet generation circuit 500 Request issuing node 600 Request receiving node 602 Busy notification generating unit

Claims (17)

A request sending means for sending a request to a request receiving node;
A request release instruction transmission means for transmitting a request release instruction for releasing a request storage location in the request reception node storing the request to the request reception node when a reply to the request is received from the request reception node;
When all of a predetermined number of the request storage locations in the request receiving node are in use, if the transmission of the request and the transmission of the request release instruction compete, the priority transmission is transmitted. A request issuing node including: arbitration means for switching to transmission of the request release instruction. When a busy notification indicating that all of the predetermined number of request storage locations are in use is received from the request receiving node, a switching signal for giving priority to transmission of the request release instruction is sent to the arbitration means,
The request issuing node according to claim 1, further comprising: a switching unit that stops transmission of the switching signal when a predetermined time has elapsed after receiving the busy notification. The switching means is
A register for storing a predetermined value;
A timer that starts counting up from an initial value when a busy notification is received from the request receiving node;
When a busy notification is received from the request receiving node, a switching signal for giving priority to transmission of the request release instruction to the arbitration unit is generated, and when the timer reaches the predetermined value, the switching signal is generated. The request issuing node according to claim 2, further comprising: a switching signal generation circuit that stops the switching. When having a plurality of request storage locations for storing requests received from the request issuing node, sending a reply to the request to the request issuing node, and receiving a request release instruction corresponding to the reply from the request issuing node Request reception storage means for releasing the request storage location in which the corresponding request is stored;
A request receiving node comprising: busy notification generating means for generating a busy notification when a predetermined number of the request storage locations in the request receiving storage means are in use. The busy notification generation means includes:
A register for storing a predetermined value;
An effective request measurement counter that increments when receiving the request from the request issuing node and decrements when receiving the request release instruction;
The request reception node according to claim 4, further comprising: a busy notification generation circuit that generates and transmits a busy notification when the value of the valid request measurement counter becomes equal to or greater than the predetermined value. The busy notification generation means includes:
A comparator that outputs 0 if the value of the valid request measurement counter is smaller than the predetermined value, and outputs 1 if the value of the valid request measurement counter is greater than or equal to the predetermined value;
A register that holds the value output by the comparator, and outputs the value held after a predetermined period;
An AND circuit that takes a product of a value output by the comparator and a value obtained by inverting the value output by the register, and outputs the value of the product;
The request receiving node according to claim 5, further comprising: a generation circuit that generates a busy notification when the product value is 1. A request issuing node and a request receiving node;
The request issuing node is
A request sending means for sending a request to a request receiving node;
A request release instruction transmission means for transmitting a request release instruction for releasing a request storage location in the request reception node storing the request to the request reception node when a reply to the request is received from the request reception node;
When all of a predetermined number of the request storage locations in the request receiving node are in use, if the transmission of the request and the transmission of the request release instruction compete, the priority transmission is transmitted. And arbitration means for switching to transmission of the request release instruction,
The request receiving node is:
When having a plurality of request storage locations for storing requests received from the request issuing node, sending a reply to the request to the request issuing node, and receiving a request release instruction corresponding to the reply from the request issuing node Request reception storage means for releasing the request storage location in which the corresponding request is stored;
A busy notification generation unit configured to generate a busy notification when a predetermined number of the request storage locations in the request reception storage unit are in use. The request issuing node is
When a busy notification indicating that all of the predetermined number of request storage locations are in use is received from the request receiving node, a switching signal for giving priority to transmission of the request release instruction is sent to the arbitration means,
The system according to claim 7, further comprising switching means for stopping transmission of the switching signal when a predetermined time has elapsed after receiving the busy notification. The switching means is
A register for storing a predetermined value;
A timer that starts counting up from an initial value when the busy notification is received from the request receiving node;
When a busy notification is received from the request receiving node, a switching signal for giving priority to transmission of the request release instruction to the arbitration unit is generated, and when the timer reaches the predetermined value, the switching signal is generated. A switching signal generating circuit for stopping The busy notification generation means includes:
A register for storing a predetermined value;
An effective request measurement counter that increments when receiving the request from the request issuing node and decrements when receiving the request release instruction;
The system according to claim 7, further comprising: a busy notification generation circuit that generates and transmits a busy notification when the value of the valid request measurement counter becomes equal to or greater than the predetermined value. The busy notification generation means includes:
A comparator that outputs 0 if the value of the valid request measurement counter is smaller than the predetermined value, and outputs 1 if the value of the valid request measurement counter is greater than or equal to the predetermined value;
A register that holds the value output by the comparator, and outputs the value held after a predetermined period;
An AND circuit that takes a product of a value output by the comparator and a value obtained by inverting the value output by the register, and outputs the value of the product;
The system according to claim 10, further comprising: a generation circuit that generates a busy notification when the product value is 1. Send the request to the request receiving node,
When a reply to the request is received from the request receiving node, a request release instruction for releasing a request storage location in the request receiving node storing the request is transmitted to the request receiving node,
When all of a predetermined number of the request storage locations in the request receiving node are in use, if the transmission of the request and the transmission of the request release instruction compete, the priority transmission is transmitted. A request issuing node control method for switching from sending to sending of the request release instruction. When receiving a busy notification indicating that all of the predetermined number of request storage locations are in use from the request receiving node, prioritize transmission of the request release instruction,
The request issuing node control method according to claim 12, wherein transmission of the request is prioritized when a predetermined time has elapsed after receiving the busy notification. Determine whether the busy notification is received,
When the busy notification is received, the timer value is set to 1,
If the busy notification is not received and the timer value is equal to a predetermined threshold, the timer value is reset to 0,
If the busy notification is not received and the timer value is greater than 0 and less than a predetermined threshold, 1 is added to the timer value;
After setting the timer value to 1, after resetting the timer value to 0, when a busy notification is not received and the timer value is 0, or after adding 1 to the timer value, Determine if the value is greater than 0,
When the timer value is greater than 0, the value of the switching signal that determines whether to give priority to the request or the request release instruction is set to 1 that gives priority to the request release instruction.
The request issuing node control method according to claim 13, wherein when the timer value is 0, the value of the switching signal is set to 0 which gives priority to the request. Store the request received from the request issuing node in the request storage location,
Sending a reply to the request to the request issuing node;
If the request release instruction corresponding to the reply is received from the request issuing node, the request storage location where the corresponding request is stored is released,
A request reception node control method for generating a busy notification when a predetermined number of the request storage locations in the request reception storage means are in use. Incrementing when receiving the request from the request issuing node, and counting the number of valid requests by decrementing when receiving the request release instruction,
Determining whether the number of valid requests is equal to or greater than a predetermined threshold;
If the number of valid requests is not greater than or equal to the predetermined threshold, the process returns to the process of counting the number of valid requests again,
If the number of valid requests at the previous count is smaller than the predetermined threshold and the number of valid requests at the current count is greater than or equal to the predetermined threshold, a busy notification is generated and transmitted.
The request receiving node control according to claim 15, wherein when the number of valid requests at the previous time and this time is equal to or greater than the predetermined threshold value, or when the busy notification is generated and transmitted, the process returns to the process of counting the number of valid requests again. Method. Request issuing node is
Send the request to the request receiving node,
When a reply to the request is received from the request receiving node, a request release instruction for releasing a request storage location in the request receiving node storing the request is transmitted to the request receiving node,
When all of a predetermined number of the request storage locations in the request receiving node are in use, if the transmission of the request and the transmission of the request release instruction compete, the priority transmission is transmitted. Switch to sending the request release instruction,
The request receiving node
Store the request received from the request issuing node in the request storage location,
Sending a reply to the request to the request issuing node;
If the request release instruction corresponding to the reply is received from the request issuing node, the request storage location where the corresponding request is stored is released,
A system control method for generating a busy notification when a predetermined number of the request storage locations in the request reception storage means are in use.

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