Abstract: A technique for triggering a system bus write command with user code includes identifying a specific store-type instruction in a user instruction sequence. The specific store-type instruction is converted into a specific request-type command, which is configured to include core permission controls (that are stored in core configuration registers of a processor core by a trusted kernel) and user created data (stored in a cache memory). Slave devices are configured through register space (that is only accessible by the trusted kernel) with respective slave permission controls. The specific request-type command is then transmitted from the cache memory, via a system bus. In this case, the slave devices that receive the specific request-type command (via the system bus) process the specific request-type command when the core permission controls are the same as the respective slave permission controls.

Abstract: A method of correcting defects in a storage array of a microprocessor, such as a cache memory, by operating the microprocessor to carry out a functional test procedure which utilizes cache memory, collecting fault data in a trace array during the functional test procedure, identifying a location of the defect in the cache memory using the fault data, and repairing the defect by setting a fuse to reroute access requests for the location to a redundant array. The fault data may include an error syndrome and a failing address. The functional test procedure creates random cache access sequences that cause varying loads of traffic in the cache memory using a test pattern based on a random seed. The functional test procedure may be carried out after completion of a nonfunctional, built-in self test of the microprocessor which sets some of the fuses.

Abstract: An efficient system for bootstrap loading scans cache lines into a cache store queue during a scan phase, and then transmits the cache lines from the cache store queue to a cache memory array during a functional phase. Scan circuitry stores a given cache line in a set of latches associated with one of a plurality of cache entries in the cache store queue, and passes the cache line from the latch set to the associated cache entry. The cache lines may be scanned from test software that is external to the computer system. Read/claim dispatch logic dispatches store instructions for the cache entries to read/claim machines which write the cache lines to the cache memory array without obtaining write permission, after the read/claim machines evaluate a mode bit which indicates that cache entries in the cache store queue are scanned cache lines. In the illustrative embodiment the cache memory is an L2 cache.

Abstract: A data processing system includes a memory subsystem and an execution unit, coupled to the memory subsystem, which executes store instructions to determine target memory addresses of store operations to be performed by the memory subsystem. The data processing system further includes a mode field having a first setting indicating strong ordering between store operations and a second setting indicating weak ordering between store operations. Store operations accessing the memory subsystem are associated with either the first setting or the second setting. The data processing system also includes logic that, based upon settings of the mode field, inserts a synchronizing operation between a store operation associated with the first setting and a store operation associated with the second setting, such that all store operations preceding the synchronizing operation complete before store operations subsequent to the synchronizing operation.

Abstract: A computer implemented method, a processor chip, a data processing system, and computer program product in a data processing system process information in a store cache of a data processing system. The store cache receives a first entry that includes a first address indicating a first segment of a cache line. The store cache then receives a second entry including a second address indicating a second segment of the cache line. Responsive to the first segment not being equal to the second segment, the first entry is chained to the second entry.

Abstract: A processor includes at least one instruction execution unit that executes store instructions to obtain store operations and a store queue coupled to the instruction execution unit. The store queue includes a queue entry in which the store queue gathers multiple store operations during a store gathering window to obtain a data portion of a write transaction directed to lower level memory. In addition, the store queue includes dispatch logic that varies a size of the store gathering window to optimize store performance for different store behaviors and workloads.

Abstract: A processor includes at least one instruction execution unit that executes store instructions to obtain store operations and a store queue coupled to the instruction execution unit. The store queue includes a queue entry in which the store queue gathers multiple store operations during a store gathering window to obtain a data portion of a write transaction directed to lower level memory. In addition, the store queue includes dispatch logic that varies a size of the store gathering window to optimize store performance for different store behaviors and workloads.

Abstract: A method, system, and processor chip design for reducing the latency between completing a LARX operation and receiving the associated STCX operation to complete the update to the cache line. Each entry of the store queue of the issuing processor is provided an additional tracking bit (priority bit). The priority bit is set whenever a STCX operation is placed within the entry. During selection of an entry for dispatch by the arbitration logic, the arbitration logic scans the value of the priority bits of each eligible entry. An entry with the priority bit set is given priority in the selection process within architectural rules. That entry is then selected for dispatch as early as is possible within the established rules.

Abstract: A cache, system and method for reducing the number of rejected snoop requests. An incoming snoop request is entered in the first available latch in a pipeline of latches in a stall/reorder unit if the stall/reorder unit is not full. The entered snoop request is dispatched to a selector upon entering a bottom latch in the pipeline. The stall/reorder unit is not informed as to whether the dispatched snoop request is accepted by an arbitration mechanism for several clock cycles after the dispatch occurred. A copy of the dispatched snoop request is stored in a top latch in an overrun pipeline of latches in the first unit upon dispatching the snoop request. By maintaining information about the snoop request, the snoop request may be dispatched again to the selector in case the dispatched snoop request was rejected thereby increasing the chance that the snoop request will ultimately be accepted.

Abstract: A method of correcting defects in a storage array of a microprocessor, such as a cache memory, by operating the microprocessor to carry out a functional test procedure which utilizes cache memory, collecting fault data in a trace array during the functional test procedure, identifying a location of the defect in the cache memory using the fault data, and repairing the defect by setting a fuse to reroute access requests for the location to a redundant array. The fault data may include an error syndrome and a failing address. The functional test procedure creates random cache access sequences that cause varying loads of traffic in the cache memory using a test pattern based on a random seed. The functional test procedure may be carried out after completion of a nonfunctional, built-in self test of the microprocessor which sets some of the fuses.

Abstract: A method and processor system that substantially eliminates data bus operations when completing updates of an entire cache line with a full store queue entry. The store queue within a processor chip is designed with a series of AND gates connecting individual bits of the byte enable bits of a corresponding entry. The AND output is fed to the STQ controller and signals when the entry is full. When full entries are selected for dispatch to the RC machines, the RC machine is signaled that the entry updates the entire cache line. The RC machine obtains write permission to the line, and then the RC machine overwrites the entire cache line. Because the entire cache line is overwritten, the data of the cache line is not retrieved when the request for the cache line misses at the cache or when data goes state before write permission is obtained by the RC machine.

Abstract: A method of correcting defects in a storage array of a microprocessor, such as a cache memory, by operating the microprocessor to carry out a functional test procedure which utilizes cache memory, collecting fault data in a trace array during the functional test procedure, identifying a location of the defect in the cache memory using the fault data, and repairing the defect by setting a fuse to reroute access requests for the location to a redundant array. The fault data may include an error syndrome and a failing address. The functional test procedure creates random cache access sequences that cause varying loads of traffic in the cache memory using a test pattern based on a random seed. The functional test procedure may be carried out after completion of a nonfunctional, built-in self test of the microprocessor which sets some of the fuses.

Abstract: A method of correcting defects in a storage array of a microprocessor, such as a cache memory, by operating the microprocessor to carry out a functional test procedure which utilizes cache memory, collecting fault data in a trace array during the functional test procedure, identifying a location of the defect in the cache memory using the fault data, and repairing the defect by setting a fuse to reroute access requests for the location to a redundant array. The fault data may include an error syndrome and a failing address. The functional test procedure creates random cache access sequences that cause varying loads of traffic in the cache memory using a test pattern based on a random seed. The functional test procedure may be carried out after completion of a nonfunctional, built-in self test of the microprocessor which sets some of the fuses.

Abstract: A data processing system includes a processor core and a memory subsystem. The memory subsystem includes a store queue having a plurality of entries, where each entry includes an address field for holding the target address of store operation, a data field for holding data for the store operation, and a virtual sync field indicating a presence or absence of a synchronizing operation associated with the entry. The memory subsystem further includes a store queue controller that, responsive to receipt at the memory subsystem of a sequence of operations including a synchronizing operation and a particular store operation, places a target address and data of the particular store operation within the address field and data field, respectively, of an entry in the store queue and sets the virtual sync field of the entry to represent the synchronizing operation, such that a number of store queue entries utilized is reduced.

Abstract: A processor includes at least one instruction execution unit that executes store instructions to obtain store operations and a store queue coupled to the instruction execution unit. The store queue includes a queue entry in which the store queue gathers multiple store operations during a store gathering window to obtain a data portion of a write transaction directed to lower level memory. In addition, the store queue includes dispatch logic that varies a size of the store gathering window to optimize store performance for different store behaviors and workloads.

Abstract: An efficient system for bootstrap loading scans cache lines into a cache store queue during a scan phase, and then transmits the cache lines from the cache store queue to a cache memory array during a functional phase. Scan circuitry stores a given cache line in a set of latches associated with one of a plurality of cache entries in the cache store queue, and passes the cache line from the latch set to the associated cache entry. The cache lines may be scanned from test software that is external to the computer system. Read/claim dispatch logic dispatches store instructions for the cache entries to read/claim machines which write the cache lines to the cache memory array without obtaining write permission, after the read/claim machines evaluate a mode bit which indicates that cache entries in the cache store queue are scanned cache lines. In the illustrative embodiment the cache memory is an L2 cache.

Abstract: A cache, system and method for reducing the number of rejected snoop requests. An incoming snoop request is entered in the first available latch in a pipeline of latches in a stall/reorder unit if the stall/reorder unit is not full. The entered snoop request is dispatched to a selector upon entering a bottom latch in the pipeline. The stall/reorder unit is not informed as to whether the dispatched snoop request is accepted by an arbitration mechanism for several clock cycles after the dispatch occurred. A copy of the dispatched snoop request is stored in a top latch in an overrun pipeline of latches in the first unit upon dispatching the snoop request. By maintaining information about the snoop request, the snoop request may be dispatched again to the selector in case the dispatched snoop request was rejected thereby increasing the chance that the snoop request will ultimately be accepted.

Abstract: A cache, system and method for reducing the number of rejected snoop requests. A “stall/reorder unit” in a cache receives a snoop request from an interconnect. The snoop request is entered in the first available latch of the stall/reorder unit unless the stall/reorder unit is full in which case the new snoop request is transmitted to a second unit configured to transmit a request to retry resending the new snoop request. Snoop requests have a higher priority than requests from processors and snoop requests are selected by the arbitration mechanism over processor requests unless the arbitration mechanism requests otherwise (“stall request”) to the stall/reorder unit. By snoop requests having a higher priority than processor requests, the number of snoop requests rejected is reduced. By having the arbitration mechanism issue a stall request, the processor will not be starved.

Abstract: A method, system, and processor chip design for reducing the latency between completing a LARX operation and receiving the associated STCX operation to complete the update to the cache line. Each entry of the store queue of the issuing processor is provided an additional tracking bit (priority bit). The priority bit is set whenever a STCX operation is placed within the entry. During selection of an entry for dispatch by the arbitration logic, the arbitration logic scans the value of the priority bits of each eligible entry. An entry with the priority bit set is given priority in the selection process within architectural rules. That entry is then selected for dispatch as early as is possible within the established rules.

Abstract: A method, system, and processor chip design for reducing the latency between completing a LARX operation and receiving the associated STCX operation to complete the update to the cache line. Each entry of the store queue of the issuing processor is provided an additional tracking bit (priority bit). The priority bit is set whenever a STCX operation is placed within the entry. During selection of an entry for dispatch by the arbitration logic, the arbitration logic scans the value of the priority bits of each eligible entry. An entry with the priority bit set is given priority in the selection process within architectural rules. That entry is then selected for dispatch as early as is possible within the established rules.