Abstract: A method, system, and device for enabling intervention across same-level cache memories. In a preferred embodiment, responsive to a cache miss in a first cache memory a direct intervention request is sent from the first cache memory to a second cache memory requesting a direct intervention that satisfies the cache miss.

Abstract: A method, system, and device for enabling intervention across same-level cache memories. In a preferred embodiment, responsive to a cache miss in a first cache memory a direct intervention request is sent from the first cache memory to a second cache memory requesting a direct intervention that satisfies the cache miss. In an alternate embodiment, direct intervention is utilized to access a same-level victim cache.

Abstract: A system and method for re-ordering store operations from a processor core to a store queue. When a store queue receives a new processor-issued store operation from the processor core, a store queue controller allocates a new entry in the store queue. In response to allocating the new entry in the store queue, the store queue controller determines whether or not the new entry is dependent on at least one other valid entry in the store queue. In response to determining the new entry is dependent on at least one other valid entry in the store queue, the store queue controller inhibits requesting of the new entry to the RC dispatch logic until each valid entry on which the new entry is dependent has been successfully dispatched to an RC machine by the RC dispatch logic.

Abstract: A cache coherency protocol that includes a modified-invalid (Mi) state, which enables execution of a DMA Claim or DClaim operation to assign sole ownership of a cache line to a device that is going to overwrite the entire cache line without cache-to-cache data transfer. The protocol enables completion of speculatively-issued full cache line writes without requiring cache-to-cache transfer of data on the data bus during a preceding DMA Claim or DClaim operation. The modified-invalid (Mi) state assigns sole ownership of the cache line to an I/O device that has speculatively-issued a DMA Write or a processor that has speculatively-issued a DCBZ operation to overwrite the entire cache line, and the Mi state prevents data being sent to the cache line from another cache since the data will most probably be overwritten.

Abstract: A method and system are disclosed for managing saved process states in a memory of a data processing system that has multiple partitions executing independent operating systems. A hypervisor manager affords access to any processor in the data processing system for the purpose of storing process states for that processor to the memory, independent of the operating system running on the processor.

Abstract: A method of correcting an error in an ECC protected mechanism of a computer system, such as a cache or system bus, by applying data with a number of bits N to an error correction code (ECC) matrix to yield an error detection syndrome, wherein the ECC matrix has a plurality of rows and columns with a given column corresponding to a respective one of the data bits, and selected bits are set in the ECC matrix along each column and each row such that encoding for the ECC matrix allows N-bit error correction and (N?1)-bit error detection. When an error is detected and after it is corrected, the corrected data is inverted and then rewritten to the cache array. The corresponding inversion bit for this entry is accordingly set to indicate that the data as currently stored is inverted.

Abstract: A processing unit for a multiprocessor data processing system includes a store-through upper level cache, an instruction sequencing unit that fetches instructions for execution, at least one instruction execution unit that executes a store-conditional instruction to determine a store target address, a store queue that, following execution of the store-conditional instruction, buffers a corresponding store operation, sequencer logic associated with the store queue. The sequencer logic, responsive to receipt of a latency indication indicating that resolution of the store-conditional operation as passing or failing is subject to significant latency, invalidates, prior to resolution of the store-conditional operation, a cache line in the store-through upper level cache to which a load-reserve operation previously bound.

Abstract: A processing unit for a multiprocessor data processing system includes a processor core including a store-through upper level cache, an instruction sequencing unit that fetches instructions for execution, a data register, and at least one instruction execution unit coupled to the instruction sequencing unit that concurrently executes multiple threads of instructions. The processor core, responsive to the at least one instruction execution unit executing a load-reserve instruction in a first thread that binds to a load target address in the store-through upper level cache during a reservation hazard window associated with a conflicting store-conditional operation of a second thread, causes a subsequent store-conditional operation of the first thread to a store target address matching the load target address to fail if the store-conditional operation of the second thread succeeds.

Abstract: A processing unit for a multiprocessor data processing system includes a processor core including a store-through upper level cache, an instruction sequencing unit that fetches instructions for execution, a data register, and at least one instruction execution unit. The instruction execution unit, responsive to receipt of a load-reserve instruction from the instruction sequencing unit, executes the load-reserve instruction to determine a load target address. The processor core, responsive to the execution of the load-reserve instruction, performs a corresponding load-reserve operation by accessing the store-through upper level cache utilizing the load target address to cause data associated with the load target address to be loaded from the store-through upper level cache into the data register and by establishing a reservation for a reservation granule including the load target address.

Abstract: A method and system are disclosed for managing a hard architected state of a processor that is critical for executing a process in the processor. A shadow copy of the hard architected state is stored from the processor to memory when an interrupt is received by the processor. The shadow copy of the hard architected permits rapid saving of the hard architected state for the interrupted process, so that the architected state of a next process can be immediately stored in the processor.

Abstract: An improved method and apparatus for selecting invalid members as victims in a least recently used cache system. An invalid cache line selection unit has an input connected to a cache directory and an output connected to a most recently used update logic. In response to a miss in the cache, an invalid cache line is identified from information in the cache directory by the invalid cache line selection unit. This invalid cache line is updated to be the next victim by the most recently used update logic, rather than attempting to override the current victim selection by a least recently used victim selection logic. The next victim also may be selected in response to a cache hit in which information from the cache directory also is read.

Abstract: Disclosed is a symmetric multiprocessor data processing system (SMP) that implements a TLBI protocol, which enables multiple TLBI operations from multiple processors within a partition to complete concurrently. Thus, a global TLB lock, synchronization, and TLB unlock is not necessary. When a TLBI instruction is executed, the master dynamically manages the behavior of the TLBI operation based on asynchronously snooping another TLBI. If concurrent TLBI management is required, then the master dynamically degrades the TLBI to a “barrier” class instruction.

Abstract: A method of correcting an error in an ECC protected mechanism of a computer system, such as a cache or system bus, by applying data with a number of bits N to an error correction code (ECC) matrix to yield an error detection syndrome, wherein the ECC matrix has a plurality of rows and columns with a given column corresponding to a respective one of the data bits, and selected bits are set in the ECC matrix along each column and each row such that encoding for the ECC matrix allows N-bit error correction and (N?1)-bit error detection. In the illustrative embodiment, the ECC matrix has an odd number of bits set in each row thereof. In the case of an ECC protected mechanism such as a memory device, these properties facilitate the use of an inversion bit for correcting hard faults in the stored data. When an error is detected and after it is corrected, the corrected data is inverted and then rewritten to the cache array.

Abstract: A method of reducing errors in a cache memory of a computer system (e.g., an L2 cache) by periodically issuing a series of purge commands to the L2 cache, sequentially flushing cache lines from the L2 cache to an L3 cache in response to the purge commands, and correcting errors (single-bit) in the cache lines as they are flushed to the L3 cache. Purge commands are issued only when the processor cores associated with the L2 cache have an idle cycle available in a store pipe to the cache. The flush rate of the purge commands can be programmably set, and the purge mechanism can be implemented either in software running on the computer system, or in hardware integrated with the L2 cache. In the case of the software, the purge mechanism can be incorporated into the operating system. In the case of hardware, a purge engine can be provided which advantageously utilizes the store pipe that is provided between the L1 and L2 caches.

Abstract: A method of reducing errors in a cache memory of a computer system (e.g., an L2 cache) by periodically issuing a series of purge commands to the L2 cache, sequentially flushing cache lines from the L2 cache to an L3 cache in response to the purge commands, and correcting errors (single-bit) in the cache lines as they are flushed to the L3 cache. Purge commands are issued only when the processor cores associated with the L2 cache have an idle cycle available in a store pipe to the cache. The flush rate of the purge commands can be programmably set, and the purge mechanism can be implemented either in software running on the computer system, or in hardware integrated with the L2 cache. In the case of the software, the purge mechanism can be incorporated into the operating system. In the case of hardware, a purge engine can be provided which advantageously utilizes the store pipe that is provided between the L1 and L2 caches.

Abstract: An integrated circuit, such as a processing unit, includes a substrate and integrated circuitry formed in the substrate. The integrated circuitry includes a processor core that executes instructions, an interconnect interface, coupled to the processor core, that supports communication between the processor core and a system interconnect external to the integrated circuit, and at least a portion of an external communication adapter, coupled to the processor core, that supports input/output communication via an input/output communication link.

Abstract: A method and system are disclosed for running a manufacturing-level test program on an installed processor by interrupting processor execution of a non-test process. Periodic execution of the manufacturing-level test program allows the processor to continually self-test during normal function operation, in order to facilitate proper maintenance and function of the processor and a data processing system of which the processor is a part.

Abstract: A method and apparatus in a data processing system for protecting against displacement of two types of cache lines using a least recently used cache management process. A first member in a class of cache lines is selected as a first substitute victim. The first substitute victim is unselectable by the least recently used cache management process, and the second substitute victim is associated with a selected member in the class of cache lines. A second member in the class of cache lines is selected as a second substitute victim. The second victim is unselectable by the least recently used cache management process, and the second substitute victim is associated with the selected member in the class of cache lines. One of the first or second substitute victims are replaced in response to a selection of the selected member as a victim when a cache miss occurs, wherein the selected member remains in the class of cache lines.

Abstract: A method and system are disclosed for managing stored soft state information, such as the contents of cache memory and address translation information that are non-critical for executing a process within a processor. The soft states of idle processes are stored in system memory in virtual caches. Cache coherency of the soft states is maintained by snooping kill-type operations against the virtual caches in system memory.

Abstract: A method and system are disclosed for pre-loading a hard architected state of a next process from a pool of idle processes awaiting execution. When an executing process is interrupted on the processor, a hard architected state, which has been pre-stored in the processor, of a next process is loaded into architected storage locations in the processor. The next process to be executed, and thus its corresponding hard architected state that is pre-stored in the processor, are determined based on priorities assigned to the waiting processes.