International Business Machines Corporation

Alfred T Watson, Iii

Miguel Comparan

Robert Allen Shearer

Russell Dean Hoover

Hans Mikael Jacobson

Ken Van Vu

Brian Michael Rogers

Andrew D Hilton

Adam James Muff

Eric Oliver Mejdrich

Bruce Martin Fleischer

Thomas Winters Fox

Jamie Randall Kuesel

Jeffrey Douglas Brown

Charles David Wait

A method and circuit arrangement provide support for a hybrid pipeline that dynamically switches between out-of-order and in-order modes. The hybrid pipeline may selectively execute instructions from at least one instruction stream that require the high performance capabilities provided by out-of-order processing in the out-of-order mode. The hybrid pipeline may also execute instructions that have strict power requirements in the in-order mode where the in-order mode conserves more power compared to the out-of-order mode. Each stage in the hybrid pipeline may be activated and fully functional when the hybrid pipeline is in the out-of-order mode. However, stages in the hybrid pipeline not used for the in-order mode may be deactivated and bypassed by the instructions when the hybrid pipeline dynamically switches from the out-of-order mode to the in-order mode. The deactivated stages may then be reactivated when the hybrid pipeline dynamically switches from the in-order mode to the out-of-order mode.

Processor with hybrid pipeline capable of operating in out-of-order and in-order modes

A method and apparatus dynamically allocates and deallocates a portion of a cache for use as a dedicated local storage. Cache lines may be dynamically allocated and deallocated for inclusion in the dedicated local storage. Cache entries that are included in the dedicated local storage may not be evicted or invalidated. Additionally, coherence is not maintained between the cache entries that are included in the dedicated local storage and the backing memory. A load instruction may be configured to allocate, e.g., lock, a portion of the data cache for inclusion in the dedicated local storage and load data into the dedicated local storage. A load instruction may be configured to read data from the dedicated local storage and to deallocate, e.g., unlock, a portion of the data cache that was included in the dedicated local storage.

Allocating cache for use as a dedicated local storage

A method and circuit arrangement utilize a low latency variable transfer network between the register files of multiple processing cores in a multi-core processor chip to support fine grained parallelism of virtual threads across multiple hardware threads. The communication of a variable over the variable transfer network may be initiated by a move from a local register in a register file of a source processing core to a variable register that is allocated to a destination hardware thread in a destination processing core, so that the destination hardware thread can then move the variable from the variable register to a local register in the destination processing core.

Low latency variable transfer network communicating variable written to source processing core variable register allocated to destination thread to destination processing core variable register allocated to source thread

A method and apparatus for transferring architected state bypasses system memory by directly transmitting architected state between processor cores over a dedicated interconnect. The transfer may be performed by state transfer interface circuitry with or without software interaction. The architected state for a thread may be transferred from a first processing core to a second processing core when the state transfer interface circuitry detects an error that prevents proper execution of the thread corresponding to the architected state. A program instruction may be used to initiate the transfer of the architected state for the thread to one or more other threads in order to parallelize execution of the thread or perform load balancing between multiple processor cores by distributing processing of multiple threads.

Transferring architected state between cores

A method and circuit arrangement utilize scan logic disposed on a multi-core processor integrated circuit device or chip to perform internal voting-based built in self test (BIST) of the chip. Test patterns are generated internally on the chip and communicated to the scan chains within multiple processing cores on the chip. Test results output by the scan chains are compared with one another on the chip, and majority voting is used to identify outlier test results that are indicative of a faulty processing core. A bit position in a faulty test result may be used to identify a faulty latch in a scan chain and/or a faulty functional unit in the faulty processing core, and a faulty processing core and/or a faulty functional unit may be automatically disabled in response to the testing.

Multi-core processor with internal voting-based built in self test (BIST)

Register file soft error recovery including a system that includes a first register file and a second register file that mirrors the first register file. The system also includes an arithmetic pipeline for receiving data read from the first register file, and error detection circuitry to detect whether the data read from the first register file includes corrupted data. The system further includes error recovery circuitry to insert an error recovery instruction into the arithmetic pipeline in response to detecting the corrupted data. The inserted error recovery instruction replaces the corrupted data in the first register file with a copy of the data from the second register file.

Register file soft error recovery

A network on chip ('NOC') comprising integrated processor ('IP') blocks, routers, memory communications controllers, and network interface controller, each IP block coupled to a router through a memory communications controller and a network interface controller, the NOC also including a port on a router of the network through which is received an invalidate command, the invalidate command including an identification of a cache line, the invalidate command representing an instruction to invalidate the cache line, the router configured to send the invalidate command to an IP block served by the router; the router further configured to send the invalidate command horizontally and vertically to neighboring routers if the port is a vertical port; and the router further configured to send the invalidate command only horizontally to neighboring routers if the port is a horizontal port.

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Rochester, MN, United States of America

Alfred T Watson, Iii