Unisys Corporation

Thomas L Nowatzki

Dennis R Konrad

Thomas P Cooper

Michael J Hill

Charles R Caldarale

Loren R Lennie

Sylvia M Wilhelmi

Barry R Ruzek

Systems and methods for monitoring performance of virtualized instructions are provided. One method includes, during emulated execution of non-native program code including non-native instructions, maintaining a program flow history in a computing system representing a flow of program execution of the non-native program code. The program flow history includes a listing of non-native jump instructions for which execution is emulated in the computing system. The method also includes capturing one or more statistics regarding performance in native execution of the non-native program code on the computing system. The method further includes correlating the one or more statistics to the program flow history to determine performance of the computing system in executing one or more non-native instructions between each of the non-native jump instructions.

Performance monitoring of virtualized instructions

Systems and methods for tracing an emulated execution order of non-native instructions based on natively executing code on a computing system having a native instruction set architecture are provided. One method includes, during emulated execution of non-native program code, maintaining a jump history in the computing system, the jump history including a listing of non-native jump instructions for which execution is emulated in the computing system. The method includes, for each of the non-native jump instructions included in the jump history, accessing non-native program code including the non-native instructions to determine one or more non-native instructions executed between the non-native jump instruction and a last-executed non-native jump instruction, and aggregating the non-native jump instruction and the one or more non-native instructions into an instruction trace.

Post-execution instruction tracing of virtualized instructions

Method and apparatus for tracking messages and transactions communicated between a number of users and a number of hosts, where the hosts are executing concurrent applications. During a first user session, a first user communicates with a first host. A counter associated with the first user session is incremented when the application creates an output message. The counter is decremented when the output message is released to the first user. A flag associated with the first user session is set and the counter is incremented once the flag is set, if an input message or committing transaction is received from the first user. The flag is cleared and the counter is decremented when the input message or committing transaction is processed by the concurrent application. The counter being decremented indicates there are no dependencies during the first user session with regard to the output message, input message, or committing transaction. If a second user session is initiated with a second host, the second host determines if there are any dependencies with the first user session. A dependency exists if the output message is created but not released, or if the input message or committing transaction is received but not processed. If there are dependencies, the first user session is reestablished to resolve the dependencies, otherwise, the second session is continued.

Protecting duplicate/lost updates against host failures

Method and apparatus for directly accessing data from, or submit runs to, another computer platform. Preferably, this is accomplished by providing a special program statement within the software code of a computer program that is executed on a local computer platform. The special program statement may include a remote request, and may call a utility that formats and sends the remote request to the desired remote computer platform. After the remote request has been processed by the desired remote computer platform, resulting data preferably is returned to the computer program on the local computer platform.

Multi-platform helper utilities

A system and method for providing transaction indivisibility in a transaction processing system through the use of commonly-accessible modules for monitoring and maintaining proper source message sequencing is provided. A source message is transmitted from the host processing unit upon recovery of a failure of the host processing unit, where the source message includes information destined for the database, and an identifying sequence number. The identifying sequence number is compared to a stored sequence number, where the stored sequence number is associated with an immediately preceding source message received prior to the failure of the host processing unit. A source message indivisibility failure is indicated where the identifying sequence number is not consecutive with respect to the stored sequence number, while the source message is added to a message execution queue if the identifying sequence number is consecutive with respect to the stored sequence number.

System for providing transaction indivisibility in a transaction

A system and method for assembling database restoration data according to transaction in a transaction processing system. Database restoration data is collated by chronologically storing updated database records in distinct storage banks partitioned according to its corresponding transaction. Resulting database record blocks from storage banks associated with completed database transactions are queued in the order that their corresponding transactions were completed. The queued database record blocks are transferred to storage media, whereby the queued database record blocks are arranged on the storage media according to transaction, and in the order that the active transactions were completed.

System and method for arranging database restoration data for efficient

Method and apparatus for providing backup memory storage for audit trail data within a computer system having a main memory storage, a non-volatile memory storage, and backup memory storage. The computer system executes a number of transaction programs which generate audit trail entries. As the audit trail entries are generated, a portion of the audit trail entries are stored in a portion of the main memory storage to create an audit trail. The audit trail entries are accumulated in the portion of the main memory storage until a request is received to write the portion of the main memory storage to a corresponding portion of the non-volatile memory. Subsequent portions of the audit trail entries are accumulated in subsequent portions of the main memory storage. An output transfer to the backup memory storage is made once a sufficient number of portions of the main memory storage have been written to corresponding portions of the non-volatile memory in order to maximize the transfer efficiency to the backup memory storage.

XPC backup for in-process audit

Method and apparatus for managing the allocation and release of memory space within a number of files shared by a number of hosts in a data processing system. A number of allocate and release tables are provided which are accessible by the number of hosts for managing the allocation and release of space within the number of files. Each one of the number of allocate and release tables corresponds to one of the number of files and provides a file location, file size, and indication to the number of hosts of which of the number of blocks within the file have been allocated and which of the number of blocks have been released. Any host may allocate one or more of the number of blocks to store messages created or received by the host by determining from the allocate and release tables which one or more of the number of blocks within one of the number of files are available. The host may then release the one or more of the number of blocks once the one or more of the number of blocks are no longer required to store the message. Once the one or more of the number of blocks are released, any of the number of hosts may allocate and release additional messages.

Shared file allocation and release

A system and method for organizing and managing recovery information on a per-transaction basis using distinct memory structures is provided. A transaction processing system includes one or more transaction request units for initiating data transactions with a database. A memory architecture includes storage modules to store transaction recovery information that is used in recovering from a transaction processing failure, and further includes transaction descriptor memory structures each of which correspond to a distinct transaction. The transaction descriptors allow access to the transaction recovery information to be isolated from other transaction recovery information. A control information field in each transaction descriptor stores a transaction identifier that identifies the distinct transaction to which it corresponds. The transaction descriptor also includes multiple information address fields, each of which includes a pointer to one of the storage modules that stores part of the transaction recovery information associated with the transaction identifier.

System and method for managing recovery information in a transaction

A system and method for balancing database transaction request distribution between various hosts in a multiprocessor transaction processing system is provided. The transaction processing system includes a database and multiple host processors each coupled to at least one database transaction request unit. Database transaction requests sent from the host processors are collectively entered into a commonly-accessible load balancing queue. Each database transaction request is accompanied by a source identifier that identifies the database transaction request unit which initiated the corresponding database transaction request. The queued database transaction requests from the load balancing queue are processed by currently-available host processors, regardless of which host processor initiated the database transaction request. A transaction request acknowledgment for each of the processed transaction requests is created and transferred to the database transaction request unit identified by their respective source identifiers.

Balanced input/output task management for use in multiprocessor

A transaction processing audit and recovery system is disclosed. After processing a transaction, an audit manager logs in audit records only changed blocks of data of a segment of a database. Upon failure of database backing storage, a prior copy of the database is reloaded to database backing storage that is available and a recovery manager reads the audit records and copies the changed blocks back to the database backing storage. An outboard file cache system is used in conjunction with the recovery manager to recover the database. The outboard file cache provides cache storage for segments of the database and writes non-contiguous blocks of one or more segments as directed in a single input/output request initiated from the recovery manager.

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Shoreview, MN, United States of America

Thomas L Nowatzki