International Business Machines Corporation

William Preston Alexander, Iii

Robert John Urquhart

Frank Eliot Levine

Robert Tod Dimpsey

Robert Francis Berry

Scott Thomas Jones

Riaz Yousuf Hussain

Chester Charles John, Jr

Kean G Kuiper

William Robert Reynolds

Geoffrey Owen Blandy

Christopher Michael Richardson

Weiming Gu

Robert J Urguhart

John Day Howard

Donald Lawrence Mulvey

Paul Jerome Kilpatrick

A method, apparatus, and computer instructions in a processor for selectively performing operations on data. An operation to be performed on data is identified to form an identified operation. A determination is made as to whether metadata identifying a state of the data is associated with the data. A determination is made as to whether the identified operation can be performed on the data based on the state of the data, in response to the metadata being associated with the data. The operation is performed on the data if the state of the data allows for the operation to be performed. The processor selectively performs the operations based on the state of the data.

Identifying access states for variables

A method and apparatus for identifying a minimum call tree data structure from a plurality of call tree data structures are provided. With the apparatus and method, call tree data structures are generated for two or more executions of a build of a computer program. The apparatus and method perform a 'tree-minimization' operation in which the two or more call trees generated during runs of the computer program are walked and only those nodes that are present in each of the tree data structures are maintained in a minimized tree data structure. In addition, the minimum values for these common nodes are maintained in the minimized tree data structure. In this way, asynchronous events are removed from the minimum tree data structure and analysis may focus on those areas of the computer program that are consistent between runs of the computer program.

Removal of asynchronous events in complex application performance analysis

Method and apparatus for identifying access states for variables

A system and method for collecting a plurality of metrics during a single run of a computer program. The mechanism of the present invention initializes a plurality of counters to count events associated with metrics of interest. The mechanism of the present invention then counts the occurrence of events associated with metrics of interest during a single execution of a computer program. When a branch has been taken, a trace record is generated for the branch taken, wherein the generated trace record contains a count of events associated with the metrics of interest for the branch taken.

System and method for collecting a plurality of metrics in a single profiling run of computer code

A method, apparatus, and computer instructions in a processor for associating a data type with a memory location. The type is associated with a location by means of metadata that is generated and manipulated by hardware instructions that are typically generated by a compiler as it generates the other instructions that comprise the machine code version of a program. A determination is made as to whether a data value about to be stored is of the required data type for that location. The hardware indicates an error condition if the types do not match.

Method and apparatus for hardware awareness of data types

A system and method for collecting a plurality of metrics during a single run of a computer program. The mechanism of the present invention initializes a plurality of counters to count events associated with metrics of interest. The mechanism of the present invention then counts the occurrence of events associated with metrics of interest during a single execution of a computer program. Responsive to a determination that a counter in a plurality of counters has generated an interrupt, the interrupt is rerouted to an interrupt handler, wherein the interrupt handler generates trace records comprising trace information corresponding to the interrupt. The mechanism of the present invention then generates profiles for the trace records, wherein the profiles differentiate the trace records based on the metric type associated with each trace record.

Instruction profiling using multiple metrics

A method, a system, an apparatus, and a computer program product are presented for loading LDIF ((Lightweight Directory Access Protocol (LDAP) Data Interchange Format) data into a directory. A single reader thread reads entries from an LDIF file; each entry is associated with a priority value, e.g., the priority value for an entry may be based on the number of delimiters in the distinguished name within the entry. Multiple loading threads concurrently add the entries into an LDAP directory in accordance with their associated priority values. The entries are added to the LDAP directory in an order of highest indicated priority to lowest indicated priority; entries that are associated with priority values that indicate equal priority are considered to be equivalent for the purposes of ordering the entries, so entries that have equal priority may be added to the LDAP directory in any order.

Method and system for maintaining consistency during multi-threaded processing of LDIF data

A method and apparatus for averaging out variations from run to run of a computer program are provided. With the apparatus and method, call trees are generated for two or more executions of a build of a computer program. The apparatus and method perform a 'tree-addition' operation in which the two or more call trees generated during runs of the computer program are added to one another to thereby accumulate statistics for each call in the call trees. These statistics may then be divided by the number of runs whose tree data structures are being accumulated. In this way, an average of the tree data structures is generated. In addition, any portions of the tree data structure that are due to asynchronous events are averaged out so that their relative affect in the resulting tree data structure is minimized.

Method and apparatus for averaging out variations in run-to-run path data of a computer program

A method and apparatus for identifying differences in runs of a computer program that are due to changes in the code of the computer program. With the apparatus and method, call trees are generated for two or more builds of a computer program. The apparatus and method perform a 'tree-subtract' operation in which the two or more call trees generated during runs of two or more different builds of a computer program are subtracted from one another to identify build to build differences in the execution of the computer program. From the resulting tree, portions of the runs of the different builds of the computer program where the resource utilization of the computer program has not changed are easily identifiable. Moreover, portions of the runs of the different builds of the computer program where there are improvements or regressions in resource utilization of the computer program may be easily identifiable.

Method and apparatus for identifying differences in runs of a computer program due to code changes

A method, apparatus, and computer instructions in a processor for checking assertions. A determination by the processor is made as to whether metadata for an assertion is associated with the memory location, in response to detecting a change in data in a memory location. The data to the assertion is compared by the processor, in response to the metadata being associated with the memory location. An error is generated by the processor if the assertion is invalid, with respect to the data. The processor checks the assertions for validity.

Method and apparatus for implementing assertions in hardware

A method, apparatus, and computer instructions in a processor for performing arithmetic operations. A data type associated with a particular memory location is used to determine if an operation about to be performed on the data in that location is legal. If the operation requires the data to have a required data type, a determination is made as to whether the operation is a legal operation based on the identified data type and the required data type. If the operation is not legal on the identified type, a determination is made as to whether data can be cast to change the identified data type to the required data type. The data is cast to the required data type if the data can be cast to form modified data, and the arithmetic operation is performed on the modified data. If the data cannot be cast to the Required type, an exception or interrupt is generated.

Method and apparatus for verifying data types to be used for instructions and casting data types if needed

A method and system for detecting and counting bytecode sequences in a data processing system is provided. A bytecode tree data structure is used to represent sequences of bytecodes. A bytecode sequence is a subset of consecutive bytecodes within the set of bytecodes. The bytecode tree data structure contains a set of nodes in which each node represents a bytecode in a bytecode sequence or subsequence and in which a path through the bytecode tree data structure represents a bytecode sequence or subsequence. Each node of the bytecode tree data structure records one or more bytecode occurrence statistics for its corresponding bytecode in a set of bytecode sequences or subsequences. In order to determine the frequency of occurrence of common bytecode sequences and subsequences, a bytecode sequence tree data structure is generated from a set of bytecode sequences. The bytecode sequence tree data structure is then convolved into a bytecode subsequence occurrence tree data structure, which is a union of all subtrees of the bytecode sequence tree data structure.

Method and system for detecting common bytecode sequences

A method and system for detecting memory leaks in an object-oriented environment during real-time trace processing is provided. During the profiling of a program executing in a data processing system, a profiler processes events caused by the execution of the program, and the profiler maintains a profile data structure containing execution-related metrics for the program. The execution-related metrics may include object allocation and deallocation metrics that are associated with object processing initiated on behalf of an executing method. An object allocator allocates objects during the execution of the program and modifies object allocation metrics in the profile data structure. Object metrics are stored in a particular location and a pointer to that location is stored in a hash table associated with the object's ID. In another embodiment the pointer to the location is stored in a shadow heap in the same relative position as the position of the object in the heap. The object allocation metrics and the object deallocation metrics may be compared to identify memory leaks.

Method and system for shadow heap memory leak detection and other heap analysis in an object-oriented environment during real-time trace processing

A method and system for detecting and recovering from errors in trace data is provided. The trace data records selected events for executing routines, and the routines corresponding to the events are represented as one or more nodes in a tree structure. The events may be entries and exits to executing methods. A trace record identifying a routine is read, and an error condition is detected in which the identified routine does not match a routine corresponding to a current node in the tree structure. The tree structure is searched for a node that corresponds to the identified routine. Performance statistics, such as execution time, are attributed to nodes in the tree structure. In response to a determination that the current node is a root node of the tree structure, then a new node for the identified routine is added to the tree structure as a child node of the root node and spliced into the tree at the root node.

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Austin, TX, United States of America

William Preston Alexander, Iii