摘要:
A coherency scheme of use with a system having a bus, a main memory, a main memory controller for accessing main memory in response to transactions received on the bus, and a set of processor modules coupled to the bus. Each processor module has a cache memory and is capable of transmitting coherent transactions on the bus to other processor modules and to the main memory controller. Each processor module detects coherent transactions issued on the bus and performs cache coherency checks for each of the coherent transactions. Each processor module has a coherency queue for storing all transactions issued on the bus and for performing coherency checks for the transactions in first-in, first-out order. When a module transmits a coherent transaction on a bus, it places its own transaction into its own coherency queue.
摘要:
A shared bus system having a bus and a set of client modules coupled to the bus. Each client module is capable of sending transactions on the bus to other client modules and receiving transactions on the bus from other client modules for processing. Each module has a queue for storing transactions received by the module for processing. A bus controller limits the types of transactions that can be sent on the bus to prevent any module's queue from overflowing.
摘要:
A shared bus system having a bus and a set of client modules coupled to the bus. Each client module is capable of sending transactions on the bus to other client modules and receiving transactions on the bus from other client modules for processing. Each module has a queue for storing transactions received by the module for processing. A bus controller limits the types of transactions that can be sent on the bus to prevent any module's queue from overflowing.
摘要:
A bus system having a bus arbitration scheme. The bus system includes a bus and a plurality of client modules coupled to the bus. Each of the client modules is capable of transmitting information on the bus to another of client module, and only one client module is entitled to transmit information on the bus at any time. A module entitled to transmit information on the bus has control of the bus for a minimum period of time defining a cycle. To determine which module is entitled to use the bus, each client module generates an arbitration signal when it seeks to transmit information on the bus. Each client module has an arbitration signal processor responsive to the arbitration signals for determining whether the module is entitled to transmit information on said bus. The system preferably also contains a host module that informs the client modules what types of transactions allowed on the bus in a given cycle. Each arbitration signal processor preferably is also responsive to the client option signals sent by the host module during an earlier cycle.
摘要:
A shared memory multiprocessor computer system in which one or more processor modules and/or input/output modules have cache memories. The main memory controller for each main memory of the system maintains a duplicate cache tag array containing current information on the status of data lines from the main memory that are stored in the cache memories. Thus, coherency checks can be performed directly by the main memory controller. This eliminates the need for each processor having a cache memory to perform a separate coherency check and to communicate the results of its coherency checks to the main memory controller, and thereby reduces delays associated with processing coherent transactions.
摘要:
Apparatus and method for efficiently sharing data in support of hardware he coherency and coordinated in software with semaphore instructions. Accordingly, a new instruction called "Load-Bias" which, in addition to normal load operations, requests a private copy of the data, and hints to the hardware cache to try to maintain ownership until the next memory reference from that processor. When used with the Cmpxchg instruction semaphore operation, the Load-Bias instruction will reduce coherency traffic, and minimize the possibility of coherency ping-ponging or system deadlock that causes the condition in which no processor is getting useful work done.
摘要:
A computing system includes a memory bus, a main memory, an I/O adapter and a processor. The main memory, the I/O adapter and the processor are connected to the bus. The I/O adapter includes a translation map. The translation map maps I/O page numbers to memory address page numbers. The translation map includes coherence indices. The processor includes a cache and an instruction execution means. The instruction execution means generates coherence indices to be stored in the translation map. The instruction execution means performs in hardware a hash operation to generate the coherence indices.
摘要:
A computing system includes a main memory and an input/output adapter. The input/output adapter accesses a translation map. The translation map maps input/output page numbers to memory address page numbers. Entries to the translation map are generated so that each entry includes an address of a data page in the main memory and transaction configuration information. The transaction configuration information is utilized by the input/output adapter during data transactions to and from the data page.
摘要:
A multiple round-robin arbitration scheme for a shared bus system that ensures forward progress by each component utilizing the shared bus. In the shared bus system, component modules arbitrate for control of the bus for one or more cycles, and send transactions on the bus during cycles in which they control the bus. The transactions are divided into a set of transaction classes. Certain classes of transactions cannot be issued during certain bus cycles. In certain other cycles, transactions of any class may be issued. The multiple round-robin arbitration scheme ensures forward progress by ensuring that each module seeking to issue a transaction of a given class obtains control of the bus during a cycle when transactions of that class can be issued.
摘要:
A method and apparatus for transferring data from a first memory location to a second memory location in a computer system. A load instruction is executed, and, in response, data is transferred from a first memory location to a second memory location during a single bus transaction. During the same bus transaction, a request is made to invalidate a copy of the data that is stored in a third memory location if the load instruction indicates to do so.