International Business Machines Corporation

Francis Michael Bartucca

Carlos P Sosa

Punit B Shah

Billy R Robinson

Clark Debs Jeffries

Norman Clark Strole

Rosemary Venema Slager

A manage-analyze-plan-execute (MAPE) loop is performed on a system-wide basis in relation to subsystems of a computing system based on one or more parameters. Performing the MAPE loop results in a performance level at which each subsystem is to operate to conserve energy utilization on the system-wide basis such that the computing system still satisfies the parameters. The subsystem the performance level at which each subsystem is to operate is communicated to the subsystem. Each subsystem operates at the performance level communicated to the subsystem.

MAPE loop performance on system-wide basis

A compiler utility assigns memory locations to alias-free variables within a computer program. The compiler utility allocates memory keys for the alias-free variables, such that access to the memory locations of the alias-free variables is granted to blocks of code that have knowledge of the memory keys. In response to a command by the user, the compiler generates code to detect violations of alias assumptions during execution of the computer program. During the compiling process, the compiler adds the generated code for detecting violations of alias assumptions to the compiled computer program.

Using memory keys to detect alias violations

A method, system and computer program product for detecting conditions of network instability. An attribute indicative of network instability, e.g., processor and/or co-processor utilization, packet arrival rates, packet peak rates, packet size distribution, packet clustering tendencies, buffer usage patterns, occurrence of peak utilization, out-of-buffer conditions, packet discard rates, may be monitored for a network device, e.g., router. The monitored attribute may be associated with a plurality of labels (variables) where a portion of those labels may be stored in a cache. A hit ratio for the cache storing labels associated with the monitored attribute may be tracked within a period of time based on the number of requested items, i.e., labels, that are currently stored in the cache. A condition of network instability may then be detected based on the hit ratio by determining if the absolute value of the acceleration of the hit ratio exceeds a threshold.

Detecting network instability

The present invention provides an improved method and system for managing peripheral bus timeouts. The method includes: sending a request to a peripheral in a performance of a task; determining that a peripheral bus timeout occurred; sending an interrupt signal; retrying for an access to the peripheral; completing the request if the retry for the access to the peripheral is successful; and resuming the performance of the task. The present invention provides a software method in which an input/output (I/O) request to a peripheral is sent by a recoverable access routine. When a bus timeout occurs, a hung bus detector asserts an interrupt signal. The peripheral bus is freed from the hung condition. The recoverable access routine is suspended, and a bus timeout interrupt handler is then loaded. The interruption and the freeing of the peripheral bus frees the microprocessor from the processing of the I/O request so that other requests may be performed. During the suspension of the recoverable access routine, a retry routine retries the I/O request. If the retry routine is successful in completing the I/O request, the result of the request is provided to the recoverable access routine, and the recoverable access routine is resumed to complete the task. In this manner, a peripheral bus timeout is managed without the need to reset the device hardware.

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Raleigh, NC, United States of America

Francis Michael Bartucca