Abstract: Embodiments relate to vectorized Galois field multiplication. An aspect includes a subdivision of first and second input operands into vector elements of equal sizes with multiple modes defined such that a base mode has a size corresponding to a smallest vector element size, which is a factor of a size of the first and second input operands, and a higher mode has a size that is a multiple of the base mode size. The vector elements of the first input operand are modified with a bit mask based on a size of the vector elements. The modified vector elements of the first input operand and the vector elements of the second input operand are input into a single hardware tree configured for subdivision into staggered subtrees a size of each of which being based on the base mode size.

Abstract: A central processing unit measurement facility is virtualized in order to support concurrent use of the facility by multiple guests executing within a virtual environment. Each guest of the environment has independent control over disablement/enablement of the facility for that guest.

Abstract: An apparatus for comparing strings comprises a first and a second set of input registers, a matrix of comparator circuits wherein rows of the matrix correspond to the first set of input registers and columns of the matrix correspond to the second set of input registers, a set of row control registers wherein each register corresponds to a row of the matrix of the comparator circuits, the matrix of comparator circuits configured to compare data provided by the first set of registers with data provided by the second set of registers according to the row control registers, and an error detection circuit configured to compare results from four comparator circuits corresponding to two adjacent rows and two columns of the matrix of comparator circuits. A method that invokes the above mentioned apparatus is also disclosed herein, along with a computer program product corresponding to the method.

Abstract: Embodiments relate to a hardware circuit that is operable as a fixed point adder and a checksum adder. An aspect includes a driving of a multifunction compression tree disposed on a circuit path based on a control bit to execute one of first and second schemes of vector input addition and a driving of a multifunction adder disposed on the circuit path based on the control bit to perform the one of the first and second schemes of vector input addition.

Abstract: An apparatus for comparing strings comprises a first and a second set of input registers, a matrix of comparator circuits wherein rows of the matrix correspond to the first set of input registers and columns of the matrix correspond to the second set of input registers, a set of row control registers wherein each register corresponds to a row of the matrix of the comparator circuits, the matrix of comparator circuits configured to compare data provided by the first set of registers with data provided by the second set of registers according to the row control registers, and an error detection circuit configured to compare results from four comparator circuits corresponding to two adjacent rows and two columns of the matrix of comparator circuits. A method that invokes the above mentioned apparatus is also disclosed herein, along with a computer program product corresponding to the method.

Abstract: An apparatus for comparing strings comprises a first and a second set of input registers, a matrix of comparator circuits wherein rows of the matrix correspond to the first set of input registers and columns of the matrix correspond to the second set of input registers, a set of row control registers wherein each register corresponds to a row of the matrix of the comparator circuits, the matrix of comparator circuits configured to compare data provided by the first set of registers with data provided by the second set of registers according to the row control registers, and an error detection circuit configured to compare results from four comparator circuits corresponding to two adjacent rows and two columns of the matrix of comparator circuits. A method that invokes the above mentioned apparatus is also disclosed herein, along with a computer program product corresponding to the method.

Abstract: An apparatus for comparing strings comprises a first and a second set of input registers, a matrix of comparator circuits wherein rows of the matrix correspond to the first set of input registers and columns of the matrix correspond to the second set of input registers, a set of row control registers wherein each register corresponds to a row of the matrix of the comparator circuits, the matrix of comparator circuits configured to compare data provided by the first set of registers with data provided by the second set of registers according to the row control registers, and an error detection circuit configured to compare results from four comparator circuits corresponding to two adjacent rows and two columns of the matrix of comparator circuits. A method that invokes the above mentioned apparatus is also disclosed herein, along with a computer program product corresponding to the method.

Abstract: Embodiments relate to controlling observability of transactional and non-transactional stores. An aspect includes receiving one or more store instructions. The one or more store instructions are initiated within an active transaction and include store data. The active transaction effectively delays committing stores to memory until successful completion of the active transaction. The store data is stored in a local storage buffer causing alterations to the local storage buffer from a first state to a second state. A signal is received that the active transaction has terminated. If the active transaction has terminated abnormally then: the local storage buffer is reverted back to the first state if the store data was stored by a transactional store instruction, and is propagated to a shared cache if the store instruction is non-transactional.

Abstract: Embodiments relate to a hardware circuit that is operable as a fixed point adder and a checksum adder. An aspect includes a driving of a multifunction compression tree disposed on a circuit path based on a control bit to execute one of first and second schemes of vector input addition and a driving of a multifunction adder disposed on the circuit path based on the control bit to perform the one of the first and second schemes of vector input addition.

Abstract: Disclosed are a method and system for measuring the performance of individual logical partitions of a logically partitioned computer system. Preferably, the method and system both hardware and firmware to allow measurement samples to be collected only for user specified zones of interest. In one embodiment, the method comprises the steps of specifying a Zone or Zones of interest (a Zone being a logical partition), collecting measurement samples only from the one or more specified Zones of interest, and measuring the performance of each of these Zones using only the measurement samples collected from said each of the Zones.

Abstract: Embodiments relate to controlling observability of transactional and non-transactional stores. An aspect includes receiving one or more store instructions. The one or more store instructions are initiated within an active transaction and include store data. The active transaction effectively delays committing stores to memory until successful completion of the active transaction. The store data is stored in a local storage buffer causing alterations to the local storage buffer from a first state to a second state. A signal is received that the active transaction has terminated. If the active transaction has terminated abnormally then: the local storage buffer is reverted back to the first state if the store data was stored by a transactional store instruction, and is propagated to a shared cache if the store instruction is non-transactional.

Abstract: Embodiments relate to tracking a transactional execution footprint. An aspect includes receiving a store instruction which includes store data. It is determined if the store instruction is executing within a transaction that effectively delays committing stores to a shared cache until the transaction has completed. The store data is stored to a cache line in a local cache. The cache line is marked as dirty if the transaction is active. The stored data that was marked as dirty in the local cache is invalidated if the transaction has terminated abnormally. The stored data is un-marked if it is determined that the transaction has successfully ended.

Abstract: A measurement sampling facility takes snapshots of the central processing unit (CPU) on which it is executing at specified sampling intervals to collect data relating to tasks executing on the CPU. The collected data is stored in a buffer, and at selected times, an interrupt is provided to remove data from the buffer to enable reuse thereof. The interrupt is not taken after each sample, but in sufficient time to remove the data and minimize data loss.

Abstract: According to an embodiment, a computer system for cache management includes a processor and a cache, the computer system configured to perform a method including receiving a first store request for a first address in the cache and receiving a first fetch request for the first address in the cache. The method also includes executing the first store request and the first fetch request, latching the first store request in a store write-back pipeline in the cache, detecting, in the processor, a conflict following execution of the first store request and the first fetch request and receiving the first store request from a recycle path including the store write-back pipeline and executing the first store request a second time.

Abstract: A measurement sampling facility takes snapshots of the central processing unit (CPU) on which it is executing at specified sampling intervals to collect data relating to tasks executing on the CPU. The collected data is stored in a buffer, and at selected times, an interrupt is provided to remove data from the buffer to enable reuse thereof. The interrupt is not taken after each sample, but in sufficient time to remove the data and minimize data loss.

Abstract: Embodiments relate to a hardware circuit that is operable as a fixed point adder and a checksum adder. An aspect includes a driving of a multifunction compression tree disposed on a circuit path based on a control bit to execute one of first and second schemes of vector input addition and a driving of a multifunction adder disposed on the circuit path based on the control bit to perform the one of the first and second schemes of vector input addition.

Abstract: Embodiments relate to vectorized Galois field multiplication. An aspect includes an input of first and second input operands of equal sizes into a single hardware tree, a calculation of a predicted parity as a parity of the first input operand ANDed with a parity of the second input operand, a comparison of the predicted parity with a parity generated on a final result of a Galois field multiplication of the first and second operands and a raising of an error based on a mismatch between the predicted parity and the generated parity.

Abstract: Embodiments relate to vectorized Galois field multiplication. An aspect includes a subdivision of first and second input operands into vector elements of equal sizes with multiple modes defined such that a base mode has a size corresponding to a smallest vector element size, which is a factor of a size of the first and second input operands, and a higher mode has a size that is a multiple of the base mode size. The vector elements of the first input operand are modified with a bit mask based on a size of the vector elements. The modified vector elements of the first input operand and the vector elements of the second input operand are input into a single hardware tree configured for subdivision into staggered subtrees a size of each of which being based on the base mode size.

Abstract: According to an embodiment, a computer system for cache management includes a processor and a cache, the computer system configured to perform a method including receiving a first store request for a first address in the cache and receiving a first fetch request for the first address in the cache. The method also includes executing the first store request and the first fetch request, latching the first store request in a store write-back pipeline in the cache, detecting, in the processor, a conflict following execution of the first store request and the first fetch request and receiving the first store request from a recycle path including the store write-back pipeline and executing the first store request a second time.

Abstract: A measurement sampling facility takes snapshots of the central processing unit (CPU) on which it is executing at specified sampling intervals to collect data relating to tasks executing on the CPU. The collected data is stored in a buffer, and at selected times, an interrupt is provided to remove data from the buffer to enable reuse thereof. The interrupt is not taken after each sample, but in sufficient time to remove the data and minimize data loss.