Patent application number | Description | Published |
20090198964 | METHOD, SYSTEM, AND COMPUTER PROGRAM PRODUCT FOR OUT OF ORDER INSTRUCTION ADDRESS STRIDE PREFETCH PERFORMANCE VERIFICATION - A method, system, and computer program product are provided for verifying out of order instruction address (IA) stride prefetch performance in a processor design having more than one level of cache hierarchies. Multiple instruction streams are generated and the instructions loop back to corresponding instruction addresses. The multiple instruction streams are dispatched to a processor and simulation application to process. When a particular instruction is being dispatched, the particular instruction's instruction address and operand address are recorded in the queue. The processor is monitored to determine if the processor executes fetch and prefetch commands in accordance with the simulation application. It is checked to determine if prefetch commands are issued for instructions having three or more strides. | 08-06-2009 |
20090210675 | METHOD AND SYSTEM FOR EARLY INSTRUCTION TEXT BASED OPERAND STORE COMPARE REJECT AVOIDANCE - A method and system for early instruction text based operand store compare avoidance in a processor are provided. The system includes a processor pipeline for processing instruction text in an instruction stream, where the instruction text includes operand address information. The system also includes delay logic to monitor the instruction stream. The delay logic performs a method that includes detecting a load instruction following a store instruction in the instruction stream, comparing the operand address information of the store instruction with the load instruction. The method also includes delaying the load instruction in the processor pipeline in response to detecting a common field value between the operand address information of the store instruction and the load instruction. | 08-20-2009 |
20090217005 | METHOD, SYSTEM, AND COMPUTER PROGRAM PRODUCT FOR SELECTIVELY ACCELERATING EARLY INSTRUCTION PROCESSING - A method for selectively accelerating early instruction processing including receiving an instruction data that is normally processed in an execution stage of a processor pipeline, wherein a configuration of the instruction data allows a processing of the instruction data to be accelerated from the execution stage to an address generation stage that occurs earlier in the processor pipeline than the execution stage, determining whether the instruction data can be dispatched to the address generation stage to be processed without being delayed due to an unavailability of a processing resource needed for the processing of the instruction data in the address generation stage, dispatching the instruction data to be processed in the address generation stage if it can be dispatched without being delayed due to the unavailability of the processing resource, and dispatching the instruction data to be processed in the execution stage if it can not be dispatched without being delayed due to the unavailability of the processing resource, wherein the processing of the instruction data is selectively accelerated using an address generation interlock scheme. A corresponding system and computer program product. | 08-27-2009 |
20090217012 | MICROARCHITECTURE, METHOD AND COMPUTER PROGRAM PRODUCT FOR EFFICIENT DATA GATHERING FROM A SET OF TRACE ARRAYS - An architecture for collecting performance data in a processor, that includes: a trace read control unit and a trace data collect unit, each unit coupled to a plurality of trace array and multiplex units for providing performance data, the coupling accomplished by a trace read control bus, a data select bus, a trace row address bus and a data return bus; wherein each of the trace array and multiplex units receives a trace read signal and provides data including trace data and the trace read signal to the trace data collect unit. A method and a computer program product are provided. | 08-27-2009 |
20100030965 | DISOWNING CACHE ENTRIES ON AGING OUT OF THE ENTRY - Caching where portions of data are stored in slower main memory and are transferred to faster memory between one or more processors and the main memory. The cache is such that an individual cache system must communicate to other associated cache systems, or check with such cache systems, to determine if they contain a copy of a given cached location prior to or upon modification or appropriation of data at a given cached location. The cache further includes provisions for determining when the data stored in a particular memory location may be replaced. | 02-04-2010 |
20110145550 | NON-QUIESCING KEY SETTING FACILITY - A non-quiescing key setting facility is provided that enables manipulation of storage keys to be performed without quiescing operations of other processors of a multiprocessor system. With this facility, a storage key, which is accessible by a plurality of processors of the multiprocessor system, is updated absent a quiesce of operations of the plurality of processors. Since the storage key is updated absent quiescing of other operations, the storage key may be observed by a processor as having one value at the start of an operation performed by the processor and a second value at the end of the operation. A mechanism is provided to enable the operation to continue, avoiding a fatal exception. | 06-16-2011 |
20110167244 | EARLY INSTRUCTION TEXT BASED OPERAND STORE COMPARE REJECT AVOIDANCE - A method and system for early instruction text based operand store compare avoidance in a processor are provided. The system includes a processor pipeline for processing instruction text in an instruction stream, where the instruction text includes operand address information. The system also includes delay logic to monitor the instruction stream. The delay logic performs a method that includes detecting a load instruction following a store instruction in the instruction stream, comparing the operand address information of the store instruction with the load instruction. The method also includes delaying the load instruction in the processor pipeline in response to detecting a common field value between the operand address information of the store instruction and the load instruction. | 07-07-2011 |
20110320774 | OPERAND FETCHING CONTROL AS A FUNCTION OF BRANCH CONFIDENCE - A system for data operand fetching control includes a computer processor that includes a control unit for determining memory access operations. The control unit is configured to perform a method. The method includes calculating a summation weight value for each instruction in a pipeline, the summation weight value calculated as a function of branch uncertainty and a pendency in which the instruction resides in the pipeline relative to other instructions in the pipeline. The method also includes mapping the summation weight value of a selected instruction that is attempting to access system memory to a memory access control, each memory access control specifying a manner of handling data fetching operations. The method further includes performing a memory access operation for the selected instruction based upon the mapping. | 12-29-2011 |
20120204010 | NON-QUIESCING KEY SETTING FACILITY - A non-quiescing key setting facility is provided that enables manipulation of storage keys to be performed without quiescing operations of other processors of a multiprocessor system. With this facility, a storage key, which is accessible by a plurality of processors of the multiprocessor system, is updated absent a quiesce of operations of the plurality of processors. Since the storage key is updated absent quiescing of other operations, the storage key may be observed by a processor as having one value at the start of an operation performed by the processor and a second value at the end of the operation. A mechanism is provided to enable the operation to continue, avoiding a fatal exception. | 08-09-2012 |
20130091343 | OPERAND FETCHING CONTROL AS A FUNCTION OF BRANCH CONFIDENCE - Data operand fetching control includes calculating a summation weight value for each instruction in a pipeline, the summation weight value calculated as a function of branch uncertainty and a pendency in which the instruction resides in the pipeline relative to other instructions in the pipeline. The data operand fetching control also includes mapping the summation weight value of a selected instruction that is attempting to access system memory to a memory access control. Each memory access control specifies a manner of handling data fetching operations. The data operand fetching control further includes performing a memory access operation for the selected instruction based upon the mapping. | 04-11-2013 |
20130096901 | Verifying Simulation Design Modifications - A mechanism is provided for verifying design modifications to a simulation design unit included within a simulation model of an integrated electronic device. A modified description is received of a simulation design unit that failed to meet an expected physical property value during an initial simulation of the entire integrated electronic device. A simulation of the simulation design unit is executed using a list of identified input signals from a trace file. The trace file is generated during the initial simulation and indicates state values for the list of identified input signals. A determination is made as to whether the simulation of the simulation design unit fails to meet the expected physical property value. An indication is generated that modifications made to an initial description of the simulation design unit are successful in response to the simulation of the simulation design unit meeting the expected physical property value. | 04-18-2013 |
20130191599 | CACHE SET REPLACEMENT ORDER BASED ON TEMPORAL SET RECORDING - A technique is provided for cache management of a cache. The processing circuit determines a miss count and a hit position field during a previous execution of an instruction requesting that a data element be stored in a cache. The miss count and the hit position field are stored for a data element corresponding to an instruction that requests storage of the data element. The processing circuit places the data element in a hierarchical order based on the miss count and/or the hit position field. The hit position field includes a hierarchical position related to the data element in the cache. | 07-25-2013 |
20130191678 | IN SITU PROCESSOR RE-CHARACTERIZATION - A re-characterization process is provided that adjusts one or more operating parameters of a processor to improve the health (e.g., reduce errors) of the processor. The parameters include voltage and/or clock frequency, as examples. The processor can be an inactive or active processor for which the re-characterization process is performed. It is performed, in one instance, by a hardware controller in real-time. | 07-25-2013 |
20130191684 | HARDWARE RECOVERY IN MULTI-THREADED PROCESSOR - A computer system includes a simultaneous multi-threading processor and memory in operable communication with the processor. The processor is configured to perform a method including running multiple threads simultaneously, detecting a hardware error in one or more hardware structures of the processing circuit, and identifying one or more victim threads of the multiple threads. The processor is further configured to identify a plurality of hardware structures associated with execution of the one or more victim threads, isolate the one or more victim threads from the rest of the multiple threads by preventing access to the plurality of hardware structures by the multiple threads, flush the one or more victim threads by resetting hardware states of the plurality of hardware structures, and restore the one or more victim threads by restoring the plurality of hardware structures to a known safe state. | 07-25-2013 |
20130191690 | IN SITU PROCESSOR RE-CHARACTERIZATION - A re-characterization process is provided that adjusts one or more operating parameters of a processor to improve the health (e.g., reduce errors) of the processor. The parameters include voltage and/or clock frequency, as examples. The processor can be an inactive or active processor for which the re-characterization process is performed. It is performed, in one instance, by a hardware controller in real-time. | 07-25-2013 |
20130191832 | MANAGEMENT OF THREADS WITHIN A COMPUTING ENVIRONMENT - Threads of a computing environment are managed to improve system performance. Threads are migrated between processors to take advantage of single thread processing mode, when possible. As an example, inactive threads are migrated from one or more processors, potentially freeing-up one or more processors to execute an active thread. Active threads are migrated from one processor to another to transform multiple threading mode processors to single thread mode processors. | 07-25-2013 |
20130191844 | MANAGEMENT OF THREADS WITHIN A COMPUTING ENVIRONMENT - Threads of a computing environment are managed to improve system performance. Threads are migrated between processors to take advantage of single thread processing mode, when possible. As an example, inactive threads are migrated from one or more processors, potentially freeing-up one or more processors to execute an active thread. Active threads are migrated from one processor to another to transform multiple threading mode processors to single thread mode processors. | 07-25-2013 |
20130198491 | MAJOR BRANCH INSTRUCTIONS WITH TRANSACTIONAL MEMORY - Major branch instructions are provided that enable execution of a computer program to branch from one segment of code to another segment of code. These instructions also create a new stream of processing at the other segment of code enabling execution of the other segment of code to be performed in parallel with the segment of code from which the branch was taken. In one example, the other stream of processing starts a transaction for processing instructions of the other stream of processing. | 08-01-2013 |
20130198492 | MAJOR BRANCH INSTRUCTIONS - Major branch instructions are provided that enable execution of a computer program to branch from one segment of code to another segment of code. These instructions also create a new stream of processing at the other segment of code enabling execution of the other segment of code to be performed in parallel with the segment of code from which the branch was taken. In one example, the other stream of processing starts a transaction for processing instructions of the other stream of processing. | 08-01-2013 |
20130198496 | MAJOR BRANCH INSTRUCTIONS - Major branch instructions are provided that enable execution of a computer program to branch from one segment of code to another segment of code. These instructions also create a new stream of processing at the other segment of code enabling execution of the other segment of code to be performed in parallel with the segment of code from which the branch was taken. In one example, the other stream of processing starts a transaction for processing instructions of the other stream of processing. | 08-01-2013 |
20130198497 | MAJOR BRANCH INSTRUCTIONS WITH TRANSACTIONAL MEMORY - Major branch instructions are provided that enable execution of a computer program to branch from one segment of code to another segment of code. These instructions also create a new stream of processing at the other segment of code enabling execution of the other segment of code to be performed in parallel with the segment of code from which the branch was taken. In one example, the other stream of processing starts a transaction for processing instructions of the other stream of processing. | 08-01-2013 |
20130246741 | RUN-TIME INSTRUMENTATION DIRECTED SAMPLING - Embodiments of the invention relate to implementing run-time instrumentation directed sampling. An aspect of the invention includes fetching a run-time instrumentation next (RINEXT) instruction from an instruction stream. The instruction stream includes the RINEXT instruction followed by a next sequential instruction (NSI) in program order. The method further includes executing the RINEXT instruction by a processor. The executing includes determining whether a current run-time instrumentation state enables setting a sample point for reporting run-time instrumentation information during program execution. Based on the current run-time instrumentation state enabling setting the sample point, the NSI is a sample instruction for causing a run-time instrumentation event. Based on executing the NSI sample instruction, the run-time instrumentation event causes recording of run-time instrumentation information into a run-time instrumentation program buffer as a reporting group. | 09-19-2013 |
20130246742 | RUN-TIME-INSTRUMENTATION CONTROLS EMIT INSTRUCTION - Embodiments of the invention relate to executing a run-time-instrumentation EMIT (RIEMIT) instruction. A processor is configured to capture the run-time-instrumentation information of a stream of instructions. The RIEMIT instruction is fetched and executed. It is determined if the current run-time-instrumentation controls are configured to permit capturing and storing of run-time-instrumentation information in a run-time-instrumentation program buffer. If the controls are configured to store run-time-instrumentation instructions, then a RIEMIT instruction specified value is stored as an emit record of a reporting group in the run-time-instrumentation program buffer. | 09-19-2013 |
20130246743 | DETERMINING THE STATUS OF RUN-TIME-INSTRUMENTATION CONTROLS - The invention relates to determining the status of run-time-instrumentation controls. The status is determined by executing a test run-time-instrumentation controls (TRIC) instruction. The TRIC instruction executed in either a supervisor state or a lesser-privileged state. The TRIC instruction determines whether the run-time-instrumentation controls have changed. The run-time-instrumentation controls are set to an initial value using a privileged load run-time-instrumentation controls (LRIC) instruction. The TRIC instruction is fetched and executed. If the TRIC instruction is enabled, then it is determined if the initial value set by the run-time-instrumentation controls has been changed. If the initial value set by the run-time-instrumentation controls has been changed, then a condition code is set to a first value. | 09-19-2013 |
20130246744 | MODIFYING RUN-TIME-INSTRUMENTATION CONTROLS FROM A LESSER-PRIVILEGED STATE - Embodiments of the invention relate to modifying run-time-instrumentation controls (MRIC) from a lesser-privileged state. The MRIC instruction is fetched. The MRIC instruction includes the address of a run-time-instrumentation control block (RICCB). The RICCB is fetched based on the address included in the MRIC instruction. The RICCB includes values for modifying a subset of the processor's run-time-instrumentation controls. The subset of run-time-instrumentation controls includes a runtime instrumentation program buffer current address (RCA) of a runtime instrumentation program buffer (RIB) location. The RIB holds run-time-instrumentation information of the events recognized by the processor during program execution. The values of the RICCB are loaded into the run-time-instrumentation controls. Event information is provided to the RIB based on the values that were loaded in the run-time-instrumentation control. | 09-19-2013 |
20130246746 | RUN-TIME INSTRUMENTATION DIRECTED SAMPLING - Embodiments of the invention relate to implementing run-time instrumentation directed sampling. An aspect of the invention includes a method for implementing run-time instrumentation directed sampling. The method includes fetching a run-time instrumentation next (RINEXT) instruction from an instruction stream. The instruction stream includes the RINEXT instruction followed by a next sequential instruction (NSI) in program order. The method further includes executing the RINEXT instruction by a processor. The executing includes determining whether a current run-time instrumentation state enables setting a sample point for reporting run-time instrumentation information during program execution. Based on the current run-time instrumentation state enabling setting the sample point, the NSI is a sample instruction for causing a run-time instrumentation event. Based on executing the NSI sample instruction, the run-time instrumentation event causes recording of run-time instrumentation information into a run-time instrumentation program buffer as a reporting group. | 09-19-2013 |
20130246747 | RUN-TIME-INSTRUMENTATION CONTROLS EMIT INSTRUCTION - Embodiments of the invention relate to executing a run-time-instrumentation EMIT (RIEMIT) instruction. A processor is configured to capture the run-time-instrumentation information of a stream of instructions. The RIEMIT instruction is fetched and executed. It is determined if the current run-time-instrumentation controls are configured to permit capturing and storing of run-time-instrumentation information in a run-time-instrumentation program buffer. If the controls are configured to store run-time-instrumentation instructions, then a RIEMIT instruction specified value is stored as an emit record of a reporting group in the run-time-instrumentation program buffer. | 09-19-2013 |
20130246748 | DETERMINING THE STATUS OF RUN-TIME-INSTRUMENTATION CONTROLS - The invention relates to determining the status of run-time-instrumentation controls. The status is determined by executing a test run-time-instrumentation controls (TRIC) instruction. The TRIC instruction is executed in either a supervisor state or a lesser-privileged state. The TRIC instruction determines whether the run-time-instrumentation controls have changed. The run-time-instrumentation controls are set to an initial value using a privileged load run-time-instrumentation controls (LRIC) instruction. The TRIC instruction is fetched and executed. If the TRIC instruction is enabled, then it is determined if the initial value set by the run-time-instrumentation controls has been changed. If the initial value set by the run-time-instrumentation controls has been changed, then a condition code is set to a first value. | 09-19-2013 |
20130246755 | RUN-TIME INSTRUMENTATION REPORTING - Embodiments of the invention relate to run-time instrumentation reporting. An instruction stream is executed by a processor. Run-time instrumentation information of the executing instruction stream is captured by the processor. Run-time instrumentation records are created based on the captured run-time instrumentation information. A run-time instrumentation sample point of the executing instruction stream on the processor is detected. A reporting group is stored in a run-time instrumentation program buffer. The storing is based on the detecting and the storing includes: determining a current address of the run-time instrumentation program buffer, the determining based on instruction accessible run-time instrumentation controls; and storing the reporting group into the run-time instrumentation program buffer based on an origin address and the current address of the run-time instrumentation program buffer, the reporting group including the created run-time instrumentation records. | 09-19-2013 |
20130246760 | CONDITIONAL IMMEDIATE VALUE LOADING INSTRUCTIONS - A data processor comprising a plurality of registers, and instruction execution circuitry having an associated instruction set, wherein the instruction set includes an instruction specifying at least a mask operand, a register operand and an immediate value operand, and the instruction execution circuitry, in response to an instance of the instruction, determines a Boolean value based on the mask operand and sets a respective one of a plurality of registers specified by the register operand of the instance to a value of the immediate value operand if the Boolean value is true. The instruction execution circuitry, in response to the instance of the instruction, may set the respective one of the plurality of registers specified by the register operand of the instance to zero if the Boolean value is false. | 09-19-2013 |
20130246769 | RUN-TIME INSTRUMENTATION MONITORING FOR PROCESSOR CHARACTERISTIC CHANGES - Embodiments of the invention relate to monitoring processor characteristic information of a processor using run-time-instrumentation. An aspect of the invention includes executing an instruction stream on the processor and detecting a run-time instrumentation sample point of the executing instruction stream on the processor. A reporting group is stored in a run-time instrumentation program buffer based on the run-time instrumentation sample point. The reporting group includes processor characteristic information associated with the processor. | 09-19-2013 |
20130246770 | CONTROLLING OPERATION OF A RUN-TIME INSTRUMENTATION FACILITY FROM A LESSER-PRIVILEGED STATE - Embodiments of the invention relate to enabling and disabling execution of a run-time instrumentation facility. An instruction for execution by the processor in a lesser privileged state is fetched by the processor. It is determined, by the processor, that the run-time instrumentation facility permits execution of the instruction in the lesser-privileged state and that controls associated with the run-time instrumentation facility are valid. The run-time instrumentation facility is disabled based on the instruction being a run-time instrumentation facility off (RIOFF) instruction. The disabling includes updating a bit in a program status word (PSW) of the processor to indicate that run-time instrumentation data should not be captured by the processor. The run-time instrumentation facility is enabled based on the instruction being a run-time instrumentation facility on (RION) instruction. The enabling includes updating the bit in the PSW to indicate that run-time instrumentation data should be captured by the processor. | 09-19-2013 |
20130246771 | RUN-TIME INSTRUMENTATION MONITORING OF PROCESSOR CHARACTERISTICS - Embodiments of the invention relate to monitoring processor characteristic information of a processor using run-time-instrumentation. An aspect of the invention includes executing an instruction stream on the processor and detecting a run-time instrumentation sample point of the executing instruction stream on the processor. A reporting group is stored in a run-time instrumentation program buffer based on the run-time instrumentation sample point. The reporting group includes processor characteristic information associated with the processor. | 09-19-2013 |
20130246773 | HARDWARE BASED RUN-TIME INSTRUMENTATION FACILITY FOR MANAGED RUN-TIMES - Embodiments of the invention relate to performing run-time instrumentation. Run-time instrumentation is captured, by a processor, based on an instruction stream of instructions of an application program executing on the processor. The capturing includes storing the run-time instrumentation data in a collection buffer of the processor. A run-time instrumentation sample point trigger is detected by the processor. Contents of the collection buffer are copied into a program buffer as a reporting group based on detecting the run-time instrumentation sample point trigger. The program buffer is located in main storage in an address space that is accessible by the application program. | 09-19-2013 |
20130246776 | RUN-TIME INSTRUMENTATION REPORTING - Embodiments of the invention relate to run-time instrumentation reporting. An instruction stream is executed by a processor. Run-time instrumentation information of the executing instruction stream is captured by the processor. Run-time instrumentation records are created based on the captured run-time instrumentation information. A run-time instrumentation sample point of the executing instruction stream on the processor is detected. A reporting group is stored in a run-time instrumentation program buffer. The storing is based on the detecting and the storing includes: determining a current address of the run-time instrumentation program buffer, the determining based on instruction accessible run-time instrumentation controls; and storing the reporting group into the run-time instrumentation program buffer based on an origin address and the current address of the run-time instrumentation program buffer, the reporting group including the created run-time instrumentation records. | 09-19-2013 |
20130247008 | HARDWARE BASED RUN-TIME INSTRUMENTATION FACILITY FOR MANAGED RUN-TIMES - Embodiments of the invention relate to performing run-time instrumentation. Run-time instrumentation is captured, by a processor, based on an instruction stream of instructions of an application program executing on the processor. The capturing includes storing the run-time instrumentation data in a collection buffer of the processor. A run-time instrumentation sample point trigger is detected by the processor. Contents of the collection buffer are copied into a program buffer as a reporting group based on detecting the run-time instrumentation sample point trigger. The program buffer is located in main storage in an address space that is accessible by the application program. | 09-19-2013 |
20130247013 | CONTROLLING OPERATION OF A RUN-TIME INSTRUMENTATION FACILITY FROM A LESSER-PRIVILEGED STATE - Embodiments of the invention relate to enabling and disabling execution of a run-time instrumentation facility. An instruction for execution by the processor in a lesser privileged state is fetched by the processor. It is determined, by the processor, that the run-time instrumentation facility permits execution of the instruction in the lesser-privileged state and that controls associated with the run-time instrumentation facility are valid. The run-time instrumentation facility is disabled based on the instruction being a run-time instrumentation facility off (RIOFF) instruction. The disabling includes updating a bit in a program status word (PSW) of the processor to indicate that run-time instrumentation data should not be captured by the processor. The run-time instrumentation facility is enabled based on the instruction being a run-time instrumentation facility on (RION) instruction. The enabling includes updating the bit in the PSW to indicate that run-time instrumentation data should be captured by the processor. | 09-19-2013 |
20130247014 | MODIFYING RUN-TIME-INSTRUMENTATION CONTROLS FROM A LESSER-PRIVILEGED STATE - Embodiments of the invention relate to modifying run-time-instrumentation controls (MRIC) from a lesser-privileged state. The MRIC instruction is fetched. The MRIC instruction includes the address of a run-time-instrumentation control block (RICCB). The RICCB is fetched based on the address included in the MRIC instruction. The RICCB includes values for modifying a subset of the processor's run-time-instrumentation controls. The subset of run-time-instrumentation controls includes a runtime instrumentation program buffer current address (RCA) of a runtime instrumentation program buffer (RIB) location. The RIB holds run-time-instrumentation information of the events recognized by the processor during program execution. The values of the RICCB are loaded into the run-time-instrumentation controls. Event information is provided to the RIB based on the values that were loaded in the run-time-instrumentation control. | 09-19-2013 |
20130275801 | RECONFIGURABLE RECOVERY MODES IN HIGH AVAILABILITY PROCESSORS - A computer program product for performing error recovery is configured to perform a method that includes creating, by a processor, a recovery checkpoint. The processor is dynamically switched into a non-recoverable processing mode of operation based on creating the software recovery checkpoint. The non-recoverable processing mode of operation is a mode in which a subset of hardware error recovery resources are powered-down or re-purposed for instruction processing. It is determined, during the non-recoverable processing mode of operation, that a new software recovery checkpoint is required. Based on the determining that a new software recovery checkpoint is required, the processor is dynamically switched into a recoverable processing mode of operation. The recoverable processing mode of operation is a mode in which hardware error recovery resources, including at least one of the hardware error recovery resources in the subset, are purposed for hardware error recovery operations. | 10-17-2013 |
20130275806 | RECONFIGURABLE RECOVERY MODES IN HIGH AVAILABILITY PROCESSORS - A method for performing error recovery that includes creating, by a processor, a recovery checkpoint. The processor is dynamically switched into a non-recoverable processing mode of operation based on creating the software recovery checkpoint. The non-recoverable processing mode of operation is a mode in which a subset of hardware error recovery resources are powered-down or re-purposed for instruction processing. It is determined, during the non-recoverable processing mode of operation, that a new software recovery checkpoint is required. Based on the determining that a new software recovery checkpoint is required, the processor is dynamically switched into a recoverable processing mode of operation. The recoverable processing mode of operation is a mode in which hardware error recovery resources, including at least one of the hardware error recovery resources in the subset, are purposed for hardware error recovery operations. | 10-17-2013 |
20130290802 | VARIABLE ACKNOWLEDGE RATE TO REDUCE BUS CONTENTION IN PRESENCE OF COMMUNICATION ERRORS - A variable write back indicator control is provided to control the amount of data to be re-transmitted when a packet error occurs. A hardware controller obtains an indication that an acknowledge rate or an amount of set write back indicators of a data frame is to be adjusted. The indication is based on an error rate of data transmission over a communication bus. Based on obtaining the indication that the amount of set write back indicators is to be adjusted, one or more write back indicators are adjusted. | 10-31-2013 |
20130290803 | VARIABLE ACKNOWLEDGE RATE TO REDUCE BUS CONTENTION IN PRESENCE OF COMMUNICATION ERRORS - A variable write back indicator control is provided to control the amount of data to be re-transmitted when a packet error occurs. A hardware controller obtains an indication that an acknowledge rate or an amount of set write back indicators of a data frame is to be adjusted. The indication is based on an error rate of data transmission over a communication bus. Based on obtaining the indication that the amount of set write back indicators is to be adjusted, one or more write back indicators are adjusted. | 10-31-2013 |
20130326256 | GENERATING MONOTONICALLY INCREASING TOD VALUES IN A MULTIPROCESSOR SYSTEM - Generating monotonically increasing time-of-day values in a multiprocessor system is provided. Synchronization impulses are received by a processor of the multiprocessor system, and an execution of a read instruction of a time-of-day value within a processor of the processors is refused, if the execution of the read instruction of the time-of-day value is requested after a predefined time after a synchronization impulse of the synchronization impulses, and if a trigger signal, indicative of new data received by a related memory system, has been received after the predefined time, wherein the memory system is external to the processor. | 12-05-2013 |
20130332670 | PROCESS IDENTIFIER-BASED CACHE DATA TRANSFER - Embodiments of the invention relate to process identifier (PID) based cache information transfer. An aspect of the invention includes sending, by a first core of a processor, a PID associated with a cache miss in a first local cache of the first core to a second cache of the processor. Another aspect of the invention includes determining that the PID associated with the cache miss is listed in a PID table of the second cache. Yet another aspect of the invention includes based on the PID being listed in the PID table of the second cache, determining a plurality of entries in a cache directory of the second cache that are associated with the PID. Yet another aspect of the invention includes pushing cache information associated with each of the determined plurality of entries in the cache directory from the second cache to the first local cache. | 12-12-2013 |
20130332672 | PROCESS IDENTIFIER-BASED CACHE INFORMATION TRANSFER - Embodiments of the invention relate to process identifier (PID) based cache information transfer. An aspect of the invention includes sending, by a first core of a processor, a PID associated with a cache miss in a first local cache of the first core to a second cache of the processor. Another aspect of the invention includes determining that the PID associated with the cache miss is listed in a PID table of the second cache. Yet another aspect of the invention includes based on the PID being listed in the PID table of the second cache, determining a plurality of entries in a cache directory of the second cache that are associated with the PID. Yet another aspect of the invention includes pushing cache information associated with each of the determined plurality of entries in the cache directory from the second cache to the first local cache. | 12-12-2013 |
20130339614 | MITIGATING CONFLICTS FOR SHARED CACHE LINES - A computer program product for mitigating conflicts for shared cache lines between an owning core currently owning a cache line and a requestor core. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes determining whether the owning core is operating in a transactional or non-transactional mode and setting a hardware-based reject threshold at a first or second value with the owning core determined to be operating in the transactional or non-transactional mode, respectively. The method further includes taking first or second actions to encourage cache line sharing between the owning core and the requestor core in response to a number of rejections of requests by the requestor core reaching the reject threshold set at the first or second value, respectively. | 12-19-2013 |
20130339617 | AUTOMATIC PATTERN-BASED OPERAND PREFETCHING - Embodiments relate to automatic pattern-based operand prefetching. An aspect includes receiving, by prefetch logic in a processor, an operand cache miss from a pipeline of the processor. Another aspect includes determining that an entry in a history table corresponding to the operand cache miss exists based on an instruction address of the operand cache miss. Yet another aspect includes, based on determining that the entry corresponding to the operand cache miss exists in the history table, issuing a prefetch instruction for a second operand based on the determined entry in the history table, and writing the determined entry into a miss buffer. | 12-19-2013 |
20130339625 | CACHE MEMORY PREFETCHING - According to exemplary embodiments, a computer program product, system, and method for prefetching in memory include determining a missed access request for a first line in a first cache level and accessing an entry in a prefetch table, wherein the entry corresponds to a memory block, wherein the entry includes segments of the memory block. Further, the embodiment includes determining a demand segment of the segments in the entry, the demand segment corresponding to a segment of the memory block that includes the first line, reading a first field in the demand segment to determine if a second line in the demand segment is spatially related with respect to accesses of the demand segment and reading a second field in the demand segment to determine if a second segment in the entry is temporally related to the demand segment. | 12-19-2013 |
20130339650 | PREFETCH ADDRESS TRANSLATION USING PREFETCH BUFFER - Embodiments relate to prefetch address translation in a computer processor. An aspect includes issuing, by prefetch logic, a prefetch request comprising a virtual page address. Another aspect includes, based on the prefetch request missing the TLB and the address translation logic of the processor being busy performing a current translation request, comparing a page of the prefetch request to a page of the current translation request. Yet another aspect includes, based on the page of the prefetch request matching the page of the current translation request, storing the prefetch request in a prefetch buffer. | 12-19-2013 |
20130339665 | COLLISION-BASED ALTERNATE HASHING - Embodiments relate to collision-based alternate hashing. An aspect includes receiving an incoming instruction address. Another aspect includes determining whether an entry for the incoming instruction address exists in a history table based on a hash of the incoming instruction address. Another aspect includes based on determining that the entry for the incoming instruction address exists in the history table, determining whether the incoming instruction address matches an address tag in the determined entry. Another aspect includes based on determining that the incoming instruction address does not match the address tag in the determined entry, determining whether a collision exists for the incoming instruction address. Another aspect includes based on determining that the collision exists for the incoming instruction address, activating alternate hashing for the incoming instruction address using an alternate hash buffer. | 12-19-2013 |
20130339666 | SPECIAL CASE REGISTER UPDATE WITHOUT EXECUTION - A method of changing a value of associated with a logical address in a computing device. The method includes: receiving an instruction at an instruction decoder, the instruction including a target register expressed as a logical value; determining at an instruction decoder that a result of the instruction is to set the target register to a constant value, the target register being in a physical register file associated with an execution unit; and mapping, in a register mapper, the logical address to a location represented by a special register tag. | 12-19-2013 |
20130339670 | REDUCING OPERAND STORE COMPARE PENALTIES - Embodiments relate to reducing operand store compare penalties by detecting potential unit of operation (UOP) dependencies. An aspect includes a computer system for reducing operation store compare penalties. The system includes memory and a processor. The system performs a method including cracking an instruction into units of operation, where each UOP includes instruction text and address determination fields. The method includes identifying a load UOP among the plurality of UOPs and comparing values of the address determination fields of the load UOP with values of address determination fields of one or more previously-decoded store UOPs. The method also includes forcing, prior to issuance of the instruction to an execution unit, a dependency between the load UOP and the one or more previously-decoded store UOPs based on the comparing. | 12-19-2013 |
20130339683 | INSTRUCTION FILTERING - Embodiments relate to instruction filtering. An aspect includes a system for instruction filtering. The system includes memory configured to store instructions accessible by a processor, and the processor includes a tracking array and a tracked instruction logic block. The processor is configured to perform a method including detecting a tracked instruction in an instruction stream, and storing an instruction address of the tracked instruction in the tracking array based on detecting and executing the tracked instruction. The method also includes accessing the tracking array based on an address of instruction data of a subsequently fetched instruction to locate the instruction address of the tracked instruction in the tracking array as an indication of the tracked instruction. Instruction text of the subsequently fetched instruction is marked to indicate previous execution based on the tracking array. An action of the tracked instruction logic block is prevented based on the marked instruction text. | 12-19-2013 |
20130339692 | MITIGATING INSTRUCTION PREDICTION LATENCY WITH INDEPENDENTLY FILTERED PRESENCE PREDICTORS - Embodiments of the disclosure include mitigating instruction prediction latency with independently filtered instruction prediction presence predictors coupled to the processor pipeline. The prediction presence predictor includes a plurality of presence predictors configured to each receive an instruction address in parallel and to generate an unfiltered indication of an associated instruction prediction. The prediction presence predictor includes a plurality of dynamic filters that are each coupled to one of the plurality of presence predictors. Each dynamic filter is configured to block the unfiltered indications based on a performance of the presence predictor it is coupled to. The prediction presence predictor further including stall determination logic coupled to the plurality of dynamic filters. The stall determination logic is configured to generate a combined indication that will stall instruction delivery, allowing potentially latent instruction predictions to be accounted for, based upon one or more non-blocked indications received from the plurality of dynamic filters. | 12-19-2013 |
20130339696 | SELECTIVELY BLOCKING BRANCH INSTRUCTION PREDICTION - Embodiments relate to selectively blocking branch instruction predictions. An aspect includes a computer system for performing selective branch prediction. The system includes memory and a processor, and the system is configured to perform a method. The method includes detecting a branch-prediction blocking instruction in a stream of instructions and blocking branch prediction of a predetermined number of branch instructions following the branch-prediction blocking instruction based on the detecting the branch-prediction blocking instruction. | 12-19-2013 |
20130339698 | SELECTIVELY BLOCKING BRANCH INSTRUCTION PREDICTION - Embodiments relate to selectively blocking branch instruction predictions. An aspect includes computer implemented method for performing selective branch prediction. The method includes detecting, by a processor, a branch-prediction blocking instruction in a stream of instructions and blocking, by the processor, branch prediction of a predetermined number of branch instructions following the branch-prediction blocking instruction based on the detecting the branch-prediction blocking instruction. | 12-19-2013 |
20140019803 | HARDWARE RECOVERY IN MULTI-THREADED PROCESSOR - A computer system includes a simultaneous multi-threading processor and memory in operable communication with the processor. The processor is configured to perform a method including running multiple threads simultaneously, detecting a hardware error in one or more hardware structures of the processing circuit, and identifying one or more victim threads of the multiple threads. The processor is further configured to identify a plurality of hardware structures associated with execution of the one or more victim threads, isolate the one or more victim threads from the rest of the multiple threads by preventing access to the plurality of hardware structures by the multiple threads, flush the one or more victim threads by resetting hardware states of the plurality of hardware structures, and restore the one or more victim threads by restoring the plurality of hardware structures to a known safe state. | 01-16-2014 |
20140082287 | CACHE MEMORY PREFETCHING - According to exemplary embodiments, a computer program product, system, and method for prefetching in memory include determining a missed access request for a first line in a first cache level and accessing an entry in a prefetch table, wherein the entry corresponds to a memory block, wherein the entry includes segments of the memory block. Further, the embodiment includes determining a demand segment of the segments in the entry, the demand segment corresponding to a segment of the memory block that includes the first line, reading a first field in the demand segment to determine if a second line in the demand segment is spatially related with respect to accesses of the demand segment and reading a second field in the demand segment to determine if a second segment in the entry is temporally related to the demand segment. | 03-20-2014 |
20140082338 | INSTRUCTION FILTERING - Embodiments relate to instruction filtering. An aspect includes a computer-implemented method for instruction filtering. The method includes detecting, by a processor, a tracked instruction in an instruction stream, and storing an instruction address of the tracked instruction in a tracking array based on detecting and executing the tracked instruction. The method also includes accessing the tracking array based on an address of instruction data of a subsequently fetched instruction to locate the instruction address of the tracked instruction in the tracking array as an indication of the tracked instruction. The method further includes marking, by the processor, instruction text of the subsequently fetched instruction to indicate that the subsequently fetched instruction is a previously executed tracked instruction based on the indication of the tracked instruction from the tracking array. The method additionally includes preventing an action of a tracked instruction logic block based on detecting the marked instruction text. | 03-20-2014 |
20140082625 | MANAGEMENT OF RESOURCES WITHIN A COMPUTING ENVIRONMENT - Resources in a computing environment are managed, for example, by a hardware controller controlling dispatching of resources from one or more pools of resources to be used in execution of threads. The controlling includes conditionally dispatching resources from the pool(s) to one or more low-priority threads of the computing environment based on current usage of resources in the pool(s) relative to an associated resource usage threshold. The management further includes monitoring resource dispatching from the pool(s) to one or more high-priority threads of the computing environment, and based on the monitoring, dynamically adjusting the resource usage threshold used in the conditionally dispatching of resources from the pool(s) to the low-priority thread(s). | 03-20-2014 |
20140082626 | MANAGEMENT OF RESOURCES WITHIN A COMPUTING ENVIRONMENT - Resources in a computing environment are managed, for example, by a hardware controller controlling dispatching of resources from one or more pools of resources to be used in execution of threads. The controlling includes conditionally dispatching resources from the pool(s) to one or more low-priority threads of the computing environment based on current usage of resources in the pool(s) relative to an associated resource usage threshold. The management further includes monitoring resource dispatching from the pool(s) to one or more high-priority threads of the computing environment, and based on the monitoring, dynamically adjusting the resource usage threshold used in the conditionally dispatching of resources from the pool(s) to the low-priority thread(s). | 03-20-2014 |
20140089732 | THREAD SPARING BETWEEN CORES IN A MULTI-THREADED PROCESSOR - Embodiments relate to thread sparing between cores in a processor. An aspect includes determining that a number of recovery attempts made by a first thread on the first core has exceeded a recovery attempt threshold, and sending a request to transfer the first thread. Another aspect includes, selecting a second core from a plurality of cores to receive the first thread from the first core, wherein the second core is selected based on the second core having an idle thread. Another aspect includes transferring a last good architected state of the first thread from the first core to the second core. Another aspect includes loading the last good architected state of the first thread by the idle thread on the second core. Yet another aspect includes resuming execution of the first thread on the second core from the last good architected state of the first thread by the idle thread. | 03-27-2014 |
20140089734 | THREAD SPARING BETWEEN CORES IN A MULTI-THREADED PROCESSOR - Embodiments relate to thread sparing between cores in a processor. An aspect includes determining that a number of recovery attempts made by a first thread on the first core has exceeded a recovery attempt threshold, and sending a request to transfer the first thread. Another aspect includes, selecting a second core from a plurality of cores to receive the first thread from the first core, wherein the second core is selected based on the second core having an idle thread. Another aspect includes transferring a last good architected state of the first thread from the first core to the second core. Another aspect includes loading the last good architected state of the first thread by the idle thread on the second core. Yet another aspect includes resuming execution of the first thread on the second core from the last good architected state of the first thread by the idle thread. | 03-27-2014 |
20140101418 | MITIGATING INSTRUCTION PREDICTION LATENCY WITH INDEPENDENTLY FILTERED PRESENCE PREDICTORS - Embodiments of the disclosure include mitigating instruction prediction latency with independently filtered instruction prediction presence predictors coupled to the processor pipeline. The prediction presence predictor includes a plurality of presence predictors configured to each receive an instruction address in parallel and to generate an unfiltered indication of an associated instruction prediction. The prediction presence predictor includes a plurality of dynamic filters that are each coupled to one of the plurality of presence predictors. Each dynamic filter is configured to block the unfiltered indications based on a performance of the presence predictor it is coupled to. The prediction presence predictor further including stall determination logic coupled to the plurality of dynamic filters. The stall determination logic is configured to generate a combined indication that will stall instruction delivery, allowing potentially latent instruction predictions to be accounted for, based upon one or more non-blocked indications received from the plurality of dynamic filters. | 04-10-2014 |
20140108743 | STORE DATA FORWARDING WITH NO MEMORY MODEL RESTRICTIONS - Embodiments relate to loading data in a pipelined microprocessor. An aspect includes issuing a load request that comprises a load address requiring at least one block of data the same size as a largest contiguous granularity of data returned from a cache. Another aspect includes determining that the load address matches at least one block address. Another aspect includes, based on determining that there is an address match, reading a data block from a buffer register and sending the data to satisfy the load request; comparing a unique set id of the data block to the set id of the matching address after sending the data block; based on determining that there is a set id match, continuing the load request, or, based on determining that there is not a set id match, setting a store-forwarding state of the matching address to no store-forwarding and rejecting the load request. | 04-17-2014 |
20140164707 | MITIGATING CONFLICTS FOR SHARED CACHE LINES - A computer program product for mitigating conflicts for shared cache lines between an owning core currently owning a cache line and a requestor core. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes determining whether the owning core is operating in a transactional or non-transactional mode and setting a hardware-based reject threshold at a first or second value with the owning core determined to be operating in the transactional or non-transactional mode, respectively. The method further includes taking first or second actions to encourage cache line sharing between the owning core and the requestor core in response to a number of rejections of requests by the requestor core reaching the reject threshold set at the first or second value, respectively. | 06-12-2014 |
20140201501 | DYNAMIC ACCESSING OF EXECUTION ELEMENTS THROUGH MODIFICATION OF ISSUE RULES - Embodiments of the invention relate to dynamically routing instructions to execution units based on detected errors in the execution units. An aspect of the invention includes a computer system including a processor having an instruction issue unit and a plurality of execution units. The processor is configured to detect an error in a first execution unit among the plurality of execution units and adjust instruction dispatch rules of the instruction issue unit based on detecting the error in the first execution unit to restrict access to the first execution unit while leaving un-restricted access to the remaining execution units of the plurality of execution units. | 07-17-2014 |
20140201508 | CONFIDENCE THRESHOLD-BASED OPPOSING BRANCH PATH EXECUTION FOR BRANCH PREDICTION - Embodiments relate to confidence threshold-based opposing path execution for branch prediction. An aspect includes determining a branch prediction for a first branch instruction that is encountered during execution of a first thread, wherein the branch prediction indicates a primary path and an opposing path for the first branch instruction. Another aspect includes executing the primary path by the first thread. Another aspect includes determining a confidence of the branch prediction and comparing the confidence of the branch prediction to a confidence threshold. Yet another aspect includes, based on the confidence of the branch prediction being less than the confidence threshold, starting a second thread that executes the opposing path of the first branch instruction, wherein the second thread is executed in parallel with the first thread. | 07-17-2014 |
20140258629 | SPECIFIC PREFETCH ALGORITHM FOR A CHIP HAVING A PARENT CORE AND A SCOUT CORE - Embodiments relate to a method, system, and computer program product for prefetching data on a chip having at least one scout core and a parent core. The method includes saving a prefetch code start address by the parent core. The prefetch code start address indicates where a prefetch code is stored. The prefetch code is specifically configured for monitoring the parent core based on a specific application being executed by the parent core. The method includes sending a broadcast interrupt signal by the parent core to the at least one scout core. The broadcast interrupt signal being sent based on the prefetch code start address being saved. The method includes monitoring the parent core by the prefetch code executed by at least one scout core. The scout core executes the prefetch code based on receiving the broadcast interrupt signal. | 09-11-2014 |
20140258630 | PREFETCHING FOR MULTIPLE PARENT CORES IN A MULTI-CORE CHIP - Embodiments relate to a method, system, and computer program product for prefetching data on a chip. The chip has at least one scout core, multiple parent cores that cooperate together to execute various tasks, and a shared cache that is common between the scout core and the multiple parent cores. An aspect of the embodiments includes monitoring the multiple parent cores by the at least one scout core through the shared cache for a shared cache access occurring in a base parent core. The method includes saving a fetch address by the at least one scout core based on the shared cache access occurring. The fetch address indicates a location of a specific line of cache requested by the base parent core. | 09-11-2014 |
20140258640 | PREFETCHING FOR A PARENT CORE IN A MULTI-CORE CHIP - Embodiments of the invention relate to prefetching data on a chip having at least one scout core, at least one parent core, and a shared cache that is common between the at least one scout core and the at least one parent core. A prefetch code is executed by the scout core for monitoring the parent core. The prefetch code executes independently from the parent core. The scout core determines that at least one specified data pattern has occurred in the parent core based on monitoring the parent core. A prefetch request is sent from the scout core to the shared cache. The prefetch request is sent based on the at least one specified pattern being detected by the scout core. A data set indicated by the prefetch request is sent to the parent core by the shared cache. | 09-11-2014 |
20140258681 | ANTICIPATED PREFETCHING FOR A PARENT CORE IN A MULTI-CORE CHIP - Embodiments relate to prefetching data on a chip having a scout core and a parent core coupled to the scout core. The method includes determining that a program executed by the parent core requires content stored in a location remote from the parent core. The method includes sending a fetch table address determined by the parent core to the scout core. The method includes accessing a fetch table that is indicated by the fetch table address by the scout core. The fetch table indicates how many of pieces of content are to be fetched by the scout core and a location of the pieces of content. The method includes based on the fetch table indicating, fetching the pieces of content by the scout core. The method includes returning the fetched pieces of content to the parent core. | 09-11-2014 |
20150019819 | PREFETCHING FOR MULTIPLE PARENT CORES IN A MULTI-CORE CHIP - Embodiments relate to a method and computer program product for prefetching data on a chip. The chip has at least one scout core, multiple parent cores that cooperate together to execute various tasks, and a shared cache that is common between the scout core and the multiple parent cores. An aspect of the embodiments includes monitoring the multiple parent cores by the at least one scout core through the shared cache for a shared cache access occurring in a base parent core. The method includes saving a fetch address by the at least one scout core based on the shared cache access occurring. The fetch address indicates a location of a specific line of cache requested by the base parent core. | 01-15-2015 |
20150019820 | PREFETCHING FOR A PARENT CORE IN A MULTI-CORE CHIP - Embodiments of the invention relate to prefetching data on a chip having at least one scout core, at least one parent core, and a shared cache that is common between the at least one scout core and the at least one parent core. A prefetch code is executed by the scout core for monitoring the parent core. The prefetch code executes independently from the parent core. The scout core determines that at least one specified data pattern has occurred in the parent core based on monitoring the parent core. A prefetch request is sent from the scout core to the shared cache. The prefetch request is sent based on the at least one specified pattern being detected by the scout core. A data set indicated by the prefetch request is sent to the parent core by the shared cache. | 01-15-2015 |
20150019821 | SPECIFIC PREFETCH ALGORITHM FOR A CHIP HAVING A PARENT CORE AND A SCOUT CORE - Embodiments relate to a method and computer program product for prefetching data on a chip having at least one scout core and a parent core. The method includes saving a prefetch code start address by the parent core. The prefetch code start address indicates where a prefetch code is stored. The prefetch code is specifically configured for monitoring the parent core based on a specific application being executed by the parent core. The method includes sending a broadcast interrupt signal by the parent core to the at least one scout core. The broadcast interrupt signal being sent based on the prefetch code start address being saved. The method includes monitoring the parent core by the prefetch code executed by at least one scout core. The scout core executes the prefetch code based on receiving the broadcast interrupt signal. | 01-15-2015 |
20150019841 | ANTICIPATED PREFETCHING FOR A PARENT CORE IN A MULTI-CORE CHIP - Embodiments relate to prefetching data on a chip having a scout core and a parent core coupled to the scout core. A method includes determining that a program executed by the parent core requires content stored in a location remote from the parent core. The method includes sending a fetch table address determined by the parent core to the scout core. The method includes accessing a fetch table that is indicated by the fetch table address by the scout core. The fetch table indicates how many of pieces of content are to be fetched by the scout core and a location of the pieces of content. The method includes based on the fetch table indicating, fetching the pieces of content by the scout core. The method includes returning the fetched pieces of content to the parent core. | 01-15-2015 |
20150019907 | DYNAMIC ACCESSING OF EXECUTION ELEMENTS THROUGH MODIFICATION OF ISSUE RULES - Embodiments of the invention relate to dynamically routing instructions to execution units based on detected errors in the execution units. An aspect of the invention includes a computer system including a processor having an instruction issue unit and a plurality of execution units. The processor is configured to detect an error in a first execution unit among the plurality of execution units and adjust instruction dispatch rules of the instruction issue unit based on detecting the error in the first execution unit to restrict access to the first execution unit while leaving un-restricted access to the remaining execution units of the plurality of execution units. | 01-15-2015 |
20150058607 | CONFIDENCE THRESHOLD-BASED OPPOSING BRANCH PATH EXECUTION FOR BRANCH PREDICTION - Embodiments relate to confidence threshold-based opposing path execution for branch prediction. An aspect includes determining a branch prediction for a first branch instruction that is encountered during execution of a first thread, wherein the branch prediction indicates a primary path and an opposing path for the first branch instruction. Another aspect includes executing the primary path by the first thread. Another aspect includes determining a confidence of the branch prediction and comparing the confidence of the branch prediction to a confidence threshold. Yet another aspect includes, based on the confidence of the branch prediction being less than the confidence threshold, starting a second thread that executes the opposing path of the first branch instruction, wherein the second thread is executed in parallel with the first thread. | 02-26-2015 |
20150089152 | MANAGING HIGH-CONFLICT CACHE LINES IN TRANSACTIONAL MEMORY COMPUTING ENVIRONMENTS - Cache lines in a computing environment with transactional memory are configurable with a coherency mode. Cache lines in full-line coherency mode are operated or managed with full-line granularity. Cache lines in sub-line coherency mode are operated or managed as sub-cache line portions of a full cache line. When a transaction accessing a cache line in full-line coherency mode results in a transactional abort, the cache line may be placed in sub-line coherency mode if the cache line is a high-conflict cache line. The cache line may be associated with a counter in a conflict address detection table that is incremented whenever a transaction conflict is detected for the cache line. The cache line may be a high-conflict cache line when the counter satisfies a high-conflict criterion, such as reaching a threshold value. The cache line may be returned to full-line coherency mode when a reset criterion is satisfied. | 03-26-2015 |
20150089153 | IDENTIFYING HIGH-CONFLICT CACHE LINES IN TRANSACTIONAL MEMORY COMPUTING ENVIRONMENTS - Cache lines in a computing environment with transactional memory are configurable with a coherency mode and are associated with a high-conflict indicator. Cache lines in full-line coherency mode are operated or managed with full-line granularity. Cache lines in sub-line coherency mode are operated or managed as sub-cache line portions of a full cache line. A cache line is placed in sub-line coherency mode based on examining the high-conflict indicator. A transaction accessing a memory address in a cache line in sub-line coherency mode marks only the sub-cache line portion associated with the memory address as transactionally accessed. The high-conflict indicator may be included in a set of descriptive bits associated with the cache line. A copy of the high-conflict indicator for a cache line in a first cache may be updated with the high-conflict indicator for the cache line in a second cache. | 03-26-2015 |
20150089154 | MANAGING HIGH-COHERENCE-MISS CACHE LINES IN MULTI-PROCESSOR COMPUTING ENVIRONMENTS - Cache lines in a multi-processor computing environment are configurable with a coherency mode. Cache lines in full-line coherency mode are operated or managed with full-line granularity. Cache lines in sub-line coherency mode are operated or managed as sub-cache line portions of a full cache line. A high-coherence-miss cache line may be placed in sub-line coherency mode. A cache line may be associated with a counter in a coherence miss detection table that is incremented whenever an access of the cache line results in a coherence request. The cache line may be a high-coherence-miss cache line when the counter satisfies a high-coherence-miss criterion, such as reaching a threshold value. The cache line may be returned to full-line coherency mode when a reset criterion is satisfied. | 03-26-2015 |
20150089155 | CENTRALIZED MANAGEMENT OF HIGH-CONTENTION CACHE LINES IN MULTI-PROCESSOR COMPUTING ENVIRONMENTS - Cache lines in a multi-processor computing environment are configurable with a coherency mode. Cache lines in full-line coherency mode are operated or managed with full-line granularity. Cache lines in sub-line coherency mode are operated or managed as sub-cache line portions of a full cache line. Communications detected on a coherence interconnect may indicate that a cache line is associated with performance-reducing events. A high-contention cache line may be placed in sub-line coherency mode. Caches accessing the cache line are notified that the cache line is in sub-line coherency mode. The cache line may be associated with a counter in a centralized detection table that is incremented based on detecting the communications. The cache line may be a high-contention cache line when the counter satisfies a high-contention criterion, such as reaching a threshold value. The cache line may be returned to full-line coherency mode when a reset criterion is satisfied. | 03-26-2015 |
20150089159 | MULTI-GRANULAR CACHE MANAGEMENT IN MULTI-PROCESSOR COMPUTING ENVIRONMENTS - Cache lines in a multi-processor computing environment are configurable with a coherency mode. Cache lines in full-line coherency mode are operated or managed with full-line granularity. Cache lines in sub-line coherency mode are operated or managed as sub-cache line portions of a full cache line. Each cache is associated with a directory having a number of directory entries and with a side table having a smaller number of entries. The directory entry for a cache line associates the cache line with a tag and a set of full-line descriptive bits. Creating a side table entry for the cache line places the cache line in sub-line coherency mode. The side table entry associates each of the sub-cache line portions of the cache line with a set of sub-line descriptive bits. Removing the side table entry may return the cache line to full-line coherency mode. | 03-26-2015 |