摘要:
In a system with multiple execution units, instructions are queued to allow efficient dispatching. One load/store unit (LSU) may have a store instruction pending to a real address and a second LSU may have a load instruction pending to the same real address. An SMT system has an atomic store quad word (SQW) instruction with a data path that is only double wide and the SQW requires two cycles to complete. The SMT system requires a method to prevent between collisions in a store reorder queue (SRQ) STQ. The real address of a load word (LW) one thread is compared to the real addresses in the SRQ of the second thread. If the SQW with a real address matching the real address of the LW has not committed both of its double words, then the LW of the second thread is rejected.
摘要:
A method and a data processing system by which population count (popcount) operations are efficiently performed without incurring the latency and loss of critical processing cycles and bandwidth of real time processing. The method comprises: identifying data to be stored to memory for which a popcount may need to be determined; speculatively performing a popcount operation on the data as a background process of the processor while the data is being stored to memory; storing the data to a first memory location; and storing a value of the popcount generated by the popcount operation within a second memory location. The method further comprises: determining a size of data; determining a granular level at which the popcount operation on the data will be performed; and reserving a size of said second memory location that is sufficiently large to hold the value of the popcount.
摘要:
A distributed data processing system executes multiple tasks within a parallel job, including a first local task on a local node and at least one task executing on a remote node, with a remote memory having real address (RA) locations mapped to one or more of the source effective addresses (EA) and destination EA of a data move operation initiated by a task executing on the local node. On initiation of the data move operation, remote asynchronous data move (RADM) logic identifies that the operation moves data to/from a first EA that is memory mapped to an RA of the remote memory. The local processor/RADM logic initiates a RADM operation that moves a copy of the data directly from/to the first remote memory by completing the RADM operation using the network interface cards (NICs) of the source and destination processing nodes, determined by accessing a data center for the node IDs of remote memory.
摘要:
A distributed data processing system executes multiple tasks within a parallel job, including a first local task on a local node and at least one task executing on a remote node, with a remote memory having real address (RA) locations mapped to one or more of the source effective addresses (EA) and destination EA of a data move operation initiated by a task executing on the local node. On initiation of the data move operation, remote asynchronous data move (RADM) logic identifies that the operation moves data to/from a first EA that is memory mapped to an RA of the remote memory. The local processor/RADM logic initiates a RADM operation that moves a copy of the data directly from/to the first remote memory by completing the RADM operation using the network interface cards (NICs) of the source and destination processing nodes, determined by accessing a data center for the node IDs of remote memory.
摘要:
A data processing system has a processor, a memory, and an instruction set architecture (ISA) that includes: an asynchronous memory mover (AMM) store (ST) instruction that initiates an asynchronous memory move operation that moves data from a first memory location having a first real address to a second memory location having a second real address by: (a) first performing a move of the data in virtual address space utilizing a source effective address a destination effective address; and (b) when the move is completed, completing a physical move of the data to the second memory location, independent of the processor. The ISA further provides an AMM terminate ST instruction for stopping an ongoing AMM operation before completion of the AMM operation, and a LD CMP instruction for checking a status of an AMM operation.
摘要:
A data processing system has a processor, a memory, and an instruction set architecture (ISA) that includes: (1) an asynchronous memory mover (AMM) store (ST) instruction initiates an asynchronous memory move operation that moves data from a first memory location having a first real address to a second memory location having a second real address by: (a) first performing a move of the data in virtual address space utilizing a source effective address a destination effective address; and (b) when the move is completed, completing a physical move of the data to the second memory location, independent of the processor. The ISA further provides (2) an AMM terminate ST instruction for stopping an ongoing AMM operation before completion of the AMM operation, and (3) a LD CMP instruction for checking a status of an AMM operation.
摘要:
A register in the control unit of the CPU that is used to keep track of the address of the current or next instruction is called a program counter. In an SMT system having two threads, the CPU has program counters for both threads and means for alternately selecting between program counters to determine which thread supplies an instruction to the instruction fetch unit (IFU). The software for the SMT assigns a priority to threads entering the code stream. Instructions from the threads are read from the instruction queues pseudo-randomly and proportional to their execution priorities in the normal power mode. If both threads have a lowest priority, a low power mode is set generating a gated select time every N clock cycles of a clock when valid instructions are loaded. N may be adjusted to vary the amount of power savings and the gated select time.
摘要:
A method performed in a data processing system initiates an asynchronous memory move (AMM) operation, whereby a processor performs a move of data in virtual address space from a first effective address to a second effective address and forwards parameters of the AMM operation to asynchronous memory mover logic for completion of the physical movement of data from a first memory location to a second memory location. The processor executes a second operation, which checks a status of the completion of the data move and returns a notification indicating the status. The notification indicates a status, which includes one of: data move in progress; data move totally done; data move partially done; data move cannot be performed; and occurrence of a translation look-aside buffer invalidate entry (TLBIE) operation. The processor initiates one or more actions in response to the notification received.
摘要:
A method and processor for avoiding check stops in speculative accesses. An execution unit, e.g., load/store unit, may be coupled to a queue configured to store instructions. A register, coupled to the execution unit, may be configured to store a value corresponding to an address in physical memory. When the processor is operating in real mode, the execution unit may retrieve the value stored in the register. Upon the execution unit receiving a speculative instruction, e.g., speculative load instruction, from the queue, a determination may be made as to whether the address of the speculative instruction is at or below the retrieved value. If the address of the speculative instruction is at or below this value, then the execution unit may safely speculatively execute this instruction while avoiding a check stop since all the addresses at or below this value are known to exist in physical memory.
摘要:
A method and processor for avoiding check stops in speculative accesses. An execution unit, e.g., load/store unit, may be coupled to a queue configured to store instructions. A register, coupled to the execution unit, may be configured to store a value corresponding to an address in physical memory. When the processor is operating in real mode, the execution unit may retrieve the value stored in the register. Upon the execution unit receiving a speculative instruction, e.g., speculative load instruction, from the queue, a determination may be made as to whether the address of the speculative instruction is at or below the retrieved value. If the address of the speculative instruction is at or below this value, then the execution unit may safely speculatively execute this instruction while avoiding a check stop since all the addresses at or below this value are known to exist in physical memory.