摘要:
A pending tag system and method to maintain data coherence in a processing node during pending transactions in a transaction pipeline. A pending tag storage unit may be coupled to a cache controller and configured to store pending tags each indicative of a coherence state for a data line corresponding to a pending transaction within the transaction pipeline. The pending tag storage unit includes a total amount of storage which is substantially less than an amount required to store tags contained in the full tag array for the cache memory. When a pending tag exists in the pending tag storage unit, the coherence state of the corresponding data line within the cache memory is dictated by the pending tag for snoop operations. Accordingly, data coherence is maintained during the period when transactions are pending, e.g., not yet presented to a processor and cache. When a pending transaction is completed, the coherence state of the corresponding data line as indicated by the fill tag array may be overwritten by the coherence state as indicated by the pending tag and the pending tag may deleted from the pending tag storage.
摘要:
A multiprocessor computer system is configured to selectively transmit address transactions through an address network using either a broadcast mode or a point-to-point mode transparent to the active devices that initiate the transactions. Depending on the mode of transmission selected, either a directory-based coherency protocol or a broadcast snooping coherency protocol is implemented to maintain coherency within the system. A computing node is formed by a group of clients which share a common address and data network. The address network is configured to determine whether a particular transaction is to be conveyed in broadcast mode or point-to-point mode. In one embodiment, the address network includes a mode table with entries which are configurable to indicate transmission modes corresponding to different regions of the address space within the node. Upon receiving a coherence request transaction, the address network may then access the table in order to determine the transmission mode, broadcast or point-to-point, which corresponds to the received transaction.
摘要:
A method is provided for a data storage system to change the RAID type, the layout characteristics, and the performance characteristics of a virtual volume mapped to logical disk regions in one or more logical disks while the data storage system remains online to a host. Another method is provided for a data storage system to consolidate space in one or more logical disks mapped to a virtual volume while the data storage system remains online to a host. The one or more logical disks can be consolidated to free unused chunklet regions for use in other logical disks.
摘要:
A method is provided for communicating data in an interconnect system comprising a plurality of nodes. In one aspect, the method includes: issuing a command packet from a first node, the command packet comprising a respective header quadword and at least one respective data quadword for conveying a command to a second node, wherein the command is selected from a group comprising a direct memory access (DMA) command, an administrative write command, a memory copy write command, and a built in self test (BIST) command; receiving the command packet at the second node; issuing an acknowledgement packet from the second node, the acknowledgement packet comprising a respective header quadword for conveying an acknowledgement that the command packet has been received at the second node.
摘要:
In a computer system implementing state transitions that change logically and atomically at an address packet independently of a response, the coherence domain is extended among distributed memory. As such, memory line ownership transfers upon request, and not upon requestor receipt of data. Requestor receipt of data is rapidly implemented by providing a ReadToShareFork transaction that simultaneously causes a write-type operation that updates invalid data from a requested memory address, and provides the updated data to the requesting device. More specifically, when writing valid data to memory, the ReadToShare Fork transaction simultaneously causes reissuance of the originally requested transaction using the same memory address and ID information. The requesting device upon recognizing its transaction ID on the bus system will pull the now valid data from the desired memory location.
摘要:
A method is provided to allow a user on a host system to update a specific snapshot in a data storage system where the user does not have other editing privileges. The method includes (1) receiving a request to update the snapshot from the user and (2) determining from an access control list if the user is permitted to update the snapshot. If the user is permitted to update the snapshot, the method includes (3) recording parameters for a VLUN (virtual logic unit) associated with the snapshot, (4) removing the VLUN from the data storage system, (5) replacing the snapshot with a new snapshot created from a parent volume of the snapshot, (6) recreating the VLUN for the new snapshot from the recorded parameters, and (7) exporting the VLUN to the host system.
摘要:
A method is provided for a data storage system to change the RAID type, the layout characteristics, and the performance characteristics of a virtual volume mapped to logical disk regions in one or more logical disks while the data storage system remains online to a host. Another method is provided for a data storage system to consolidate space in one or more logical disks mapped to a virtual volume while the data storage system remains online to a host. The one or more logical disks can be consolidated to free unused chunklet regions for use in other logical disks.
摘要:
A method is provided for a data storage system to move data from a source logical disk (LD) region to a target LD region while the data storage system remains online to a host. The method includes determining if a region move will create excessive load so the data storage system appears offline to the host. If not, the method includes causing writes to the source LD region to be mirrored to the target LD region, causing data in the source LD region to be copied to the target LD region, blocking reads and writes to the data storage system, and flushing dirty cache in the data storage system. If flushing the dirty cache is fast so the data storage system appears online to the host, the method includes updating mappings of the virtual volume to the LD regions and resuming the reads and writes to the data storage system.
摘要:
A multiprocessor computer system to selectively transmit address transactions using a broadcast mode or a point-to-point mode. Either a directory-based coherency protocol or a broadcast snooping coherency protocol is implemented to maintain coherency. A node is formed by a group of clients which share a common address and data network. The address network determines whether a transaction is conveyed in broadcast mode or point-to-point mode. The address network includes a table with entries which indicate transmission modes corresponding to different regions of the address space within the node. Upon receiving a coherence request transaction, the address network may access the table to determine the transmission mode which corresponds to the received transaction. Network congestion may be monitored and transmission modes adjusted accordingly. When network utilization is high, the number of transactions which are broadcast may be reduced. Alternatively, when network utilization is low, the number of broadcasts may be increased.
摘要:
In a multiprocessor system, a method, apparatus, and article of manufacture for maintaining the proper sequence of store/write operations between multiple processors to remote I/O devices without requiring changes to application software. A synchronizer is employed to synchronize write operations to the remote I/O device, and the write operations are synchronized individually upon detection and emulation, or as a group upon detection of the release of a mutual exclusion lock.