摘要:
A system for arbitrating a transmission of data includes a number K of transmitters, a request signal transmission device, a device valid signal transmission device, and a data valid logic device, wherein a transmitter asserts a request signal to request permission to begin a data transmission and transmits transmission-identifying information to a receiver. The data valid logic device deasserts a data valid signal based on the state of a wait signal, thereby preventing a transmission of data from each of the K transmitters at one clock cycle after a clock cycle at which the data signal is deasserted. An arbitration logic device of the receiver selects one of the number K of transmitters to grant permission to transmit data to the receiver and outputs an arbitration signal to a wait logic device instructing the wait logic device to deassert the wait signal of the selected trnasmitter.
摘要:
A data flow management system and method in which an application and its clients are made aware of the available credits for each type of transfer before the transfer is attempted. This enables the clients to transmit packets only when the RX side has issued a sufficient number of credits to insure that the transmission will not be stalled. The invention eliminates the need for FIFO buffers in the PCI-Express core, since the application will not transmit packets to the core until the required number of credits for the particular transfer type is available. Therefore, packet transmissions do not require buffering in the core, as they are only sent when they can be sent all the way through the core to the link. The efficient back-to-back transfer support enabled by this protocol increases the overall throughput and efficiency of the system as transfers through the application interface have fewer gaps therebetween, because the credit management protocol with its back-to-back feature reduces the idle times between packets traversing the application interface. An enhanced Quality of Service feature is also introduced by creating an environment where the low-latency packets can receive a highest attention and the lowest transmission wait time.
摘要:
A data transfer device is disclosed for writing data to and reading data from a disk drive system through a plurality of ports of the data transfer device. The data transfer device includes a first buffer for serially receiving, from a host system, control portions of data read requests and data write transfers; a second buffer for serially receiving, from the host system, data portions of data write transfers received by the first buffer; and N temporary storage devices, wherein N is a positive integer, coupled to the first buffer and the second buffer, the N temporary storage devices for parallelly receiving and temporarily storing consecutive control portions of the data read transfers and data write transfers from the first buffer. Up to N of the data read transfers and data write transfers are transferred to the disk drive system through the plurality of ports simultaneously.
摘要:
A system for maintaining data coherency. The system includes a plurality of processors. A plurality of resources is also included. One portion of the resources is sharable with the plurality of processors and each one of the other ones of the resources being dedicated to a predetermined one of the processors. The system also includes a plurality of buffers. Each one of the buffers is associated with a corresponding one of the plurality of processors. Each one of the buffers is adapted to successively store information presented thereto in successive locations of such one of the buffers. The information includes requests from the corresponding one of the processor. The system includes a logic section responsive to each one of the requests provided by the plurality of processors. The logic section produces indicia indicating whether or not such one of the requests is a request for an operation with one of the sharable resources. The logic section inserts the indicia into a succeeding one of the locations of the buffers associated with such one of the processor providing such one of the requests. The logic section also simultaneously inserts such indicia into a next succeeding available location of the other ones of the plurality of buffers. The logic section inhibits execution of requests in the buffers stored in locations thereof succeeding the location having stored therein any such inserted indicia.
摘要:
A system for transferring data packets between a data packet transfer core and a number of clients of an application layer, including an interface between the data packet transfer core and the application layer for transferring data packets from the packet transfer core to a first client and a second client. The data packet transfer core includes a number of core buffers for receiving data packet transfers input to the data packet transfer core. Each of the number of core buffers include a cut-through data path including a register and a bypass data path, the bypass data path transferring data packets from an input to the register to an output of the register without passing through the register. The system further includes a first data path from the first interface to the first client and a second data path from the interface to the second client, the second data path including an application layer buffer having an input coupled to the interface and an output coupled to the second client, the application layer buffer being for storing data packets transmitted to the second client when data packets are transmitted to the second client at a rate that is faster than the second client is able to receive the data packets. In a first mode of operation, data packets transmitted from the data packet transfer core to the first client are transferred through the bypass data path of at least one of the number of core buffers, over the interface and directly to the first client over the first data path.
摘要:
A system for transferring packets between a packet transfer core and an application layer device over an application layer interface includes a buffer system disposed in the packet transfer core having an input for receiving packets from a packet source; an output for transferring packets to the application layer interface; a buffer device having an input coupled to the input of the buffer system and an output; a selection device having a first input coupled to the output of the buffer device, a control input and an output coupled to the output of the buffer system; and a bypass path coupled between the input of the buffer system and a second input of the selection device. The control input of the selection device receives a first wait signal from the application layer device which is not asserted in a first mode of operation and asserted in a second mode of operation. In the first mode of operation, packets are transferred from the input of the buffer system to the output of the buffer system via the bypass path and, in the second mode of operation, packets are transferred from the input of the buffer system to the buffer device, and are store in the buffer device without being transferred to the output of the buffer system until the first wait signal from the application layer device is deasserted.
摘要:
A system for detecting transmission errors in a data transmission system includes a receiver for receiving a data packet transmitted thereto by a corresponding transmitter and transmitting the data packet to a destination device and an error detection device for receiving a plurality of protocol signals that control the operation of the transmitter and the receiver. The error detection device applies at least one predetermined rule to the protocol signals, wherein a violation of the at least one rule by the protocol signals indicates that an error in the transmission of the packet has occurred, and asserts an error signal when the at least one rule has been violated by the protocol signals. The system further includes a packet filtering device coupled to receive the error signal from the error detection device and the data packet from the receiver, wherein, upon receiving the asserted error signal, the packet filtering device terminates the transmission of the data packet to the destination device.
摘要:
A system for controlling packet transfers includes a packet transfer core; an application layer coupled to the packet transfer core by an application interface; a buffer in the packet transfer core for receiving packets from a packet source and transferring the packets to the application layer over the application interface, the packets comprising one or more words; a register in the application layer for receiving packets from the application interface; and a client device for receiving packets transferred thereto from the register. When the client is unable to receive packets from the register, the client asserts a first wait signal to the register, causing the register to continue receiving packets from the interface and storing the packets without transferring the packets to the client. When the register is unable to continue receiving packets from the interface, the register asserts a second wait signal to the buffer over the application interface, causing the buffer to continue receiving packets from the packet source and storing the packets without transferring packets to the interface.
摘要:
A data transfer system includes a PCI Express transaction layer having an input for serially receiving posted and non-posted request packets and completion packets; an application layer coupled to the PCI Express transaction layer for receiving posted and non-posted request packets and completion packets from the PCI Express transaction layer; a first transmission interface coupling the application layer to the PCI Express transaction layer; and a second transmission interface coupling the application layer to the PCI Express transaction layer. The PCI Express transaction layer transmits posted and non-posted request packets to the application layer over the first transmission interface and transmits completion packets to the application layer over the second transmission interface.
摘要:
A data packet arbitration system for routing data transfers from a plurality of clients to a data transmission line is described. The system includes multiple arbitration stages for transferring data from the plurality of clients to the data transmission line. Data transfers are routed through the system based on arbitration logic that prioritizes by function in a primary arbitration stage and by client in a subsequent arbitration stage.