International Business Machines Corporation

Enio Manuel Pineda

Frank Eliot Levine

Jimmie Earl DeWitt, Jr

Robert John Urquhart

Kean G Kuiper

Wen-Tzer Thomas Chen, Jr

Robert Francis Berry

Scott Thomas Jones

Christopher Michael Richardson

David Kevin Siegwart

Jesse Mannes Gordon

Donald Lawrence Mulvey

Riaz Yousuf Hussain

Robert Tod Dimpsey

Chester Charles John, Jr

John Day Howard

Milena Milenkovic

Benjamin Joseph Hoflich

Robert Todd Dimpsey

The present disclosure provides a computer program product and activity recording system for identifying idleness in a processor via a concurrent software environment. A thread state indicator records an indication of a synchronization state of a software thread that is associated with an identification of the software thread. A time profiler identifies a processor of the computer system being idle and records an indication that the processor is idle. A dispatch monitor identifies a dispatch of the software thread to the processor. In response to the dispatch monitor determining the indication identifies that the processor is idle and the indication of a synchronization state of the software thread indicating the software thread ceases to execute in the processor, the dispatch monitor generates a record attributing the idleness of the processor to the software thread and the indicated synchronization state.

Recording activity of software threads in a concurrent software environment

The present disclosure provides a method for identifying idleness in a processor via a concurrent software environment. A thread state indicator records an indication of a synchronization state of a software thread that is associated with an identification of the software thread. A time profiler identifies a processor of the computer system being idle and records an indication that the processor is idle. A dispatch monitor identifies a dispatch of the software thread to the processor. In response to the dispatch monitor determining the indication identifies that the processor is idle and the indication of a synchronization state of the software thread indicating the software thread ceases to execute in the processor, the dispatch monitor generates a record attributing the idleness of the processor to the software thread and the indicated synchronization state.

Synchronization activity recording system for a concurrent software environment

A process generates a sample based on an event. The process identifies, with a dispatch monitor, a next dispatched monitored thread that is dispatched by a current processor. The process sets a processor affinity of the next dispatched monitored thread such that the next dispatched monitored thread runs only on the current processor without being able to migrate to a different processor. The process also retrieves, with a sampled thread that runs on the current processor, a next dispatched monitored thread call stack after the processor affinity of the next dispatched monitored thread has been set to the processor. The process restores the processor affinity of the next dispatched monitored thread after the next dispatched monitored thread call stack has been obtained.

Idle transitions sampling with execution context

A sample is generated based on an event. Further, an interrupt handler captures information for an interrupted thread on a current processor. In addition, an affinity of the interrupted thread is set such that the interrupted thread runs only on the current processor without being able to migrate to a different processor. A sampler thread that runs on the current processor retrieves a call stack associated with the interrupted thread after the affinity of the interrupted thread has been set to the current processor. The affinity of the interrupted thread is restored after the call stack has been retrieved.

Performing call stack sampling by setting affinity of target thread to a current process to prevent target thread migration

A computer implemented method, apparatus, and computer usable program code for sampling call stack information. Monitoring for an event is performed during an execution of a plurality of threads by a set of processors. A portion of the plurality of threads is identified based on a policy to form a set of identified threads in response to an occurrence of the event. Call stack information is collected for the set of identified threads using an under utilized processor in a set of processors in response to identifying the portion of the plurality of threads, wherein the call stack information is used to profile a processor in the set of processors.

Call stack sampling to obtain information for analyzing idle states in a data processing system

A data processing system for processing instructions is shown. Instructions are received at a processor in the data processing system. If a selected indicator is associated with the instruction, counting of each event associated with the execution of the instruction is enabled.

Counting instruction execution and data accesses

A computer implemented method, apparatus, and computer program product for executing instructions. A determination is made as to whether a set of instructions are a set of instrumentation instructions in response to identifying the set of instructions in instructions for execution. A further determination is made as to whether a processor executing the instructions is in an instrumentation mode if the set of instructions are instrumentation instructions. The processor executes the set of instrumentation instructions only if the processor is in the instrumentation mode.

Selectively marking and executing instrumentation code

A computer implemented method, apparatus, and computer usable program code for sampling call stack information. An event is monitored during execution of a plurality of threads executed by a plurality of processors. In response to an occurrence of the event, a thread is identified in the plurality of threads to form an identified thread. A plurality of sampling threads is woken, wherein a sampling thread within the plurality of sampling threads is associated with each processor in the plurality of processors and wherein one sampling thread in the plurality of sampling threads obtains call stack information for the identified thread.

Call stack sampling in a data processing system

A system and method for Java&#x2122; call stack sampling combined with native sampling is presented. A kernel-mode device driver records and stores sampled context information that includes a program counter, a thread identifier, and a process identifier. The sampling thread receives a notification from the kernel-mode device driver, and proceeds to collect call stack information from a Java&#x2122; Virtual Machine. In turn, the sampling thread retrieves the sampled context information and harvests symbols corresponding to a loaded module. Once symbols are harvested, the sampling thread combines returned call stack nodes with native function leaf nodes into a unified output tree that provides the relationship between the two different node types. In one embodiment, the sampling thread may generate native function leaf nodes and the unified output tree in a post-processing manner.

System and method for call stack sampling combined with node and instruction tracing

A method, apparatus, and computer instructions in a data processing system for monitoring the execution of instructions and accesses to memory locations. If an instruction is associated with a indicator, a counter associated with the instruction is incremented in response to detecting execution of the instruction. The indicator may be associated with a memory location with a counter associated with the memory location being incremented in response to an access of the memory location.

Method and apparatus for counting execution of specific instructions and accesses to specific data locations

A computer implemented method, apparatus, and computer usable program code to collect information for a system or processor having a transition between an idle state and a non-idle state to form collected system or processor information. The collected system or processor information is provided for analysis by an application. Idle counts occurring during execution of code are collected. The idle counts are provided to an application for analyzing why a processor becomes idle.

Method and apparatus for analyzing idle states in a data processing system

A computer implemented method, apparatus, and computer usable code for identifying processor utilization. A current event is detected. A number of elapsed cycles for a processor since a previous event are identified in response to detecting the current event. An elapsed time using the number of elapsed cycles and a current frequency of the processor is calculated, wherein the elapsed time is used to identify the processor utilization.

Adaptive processor utilization reporting handling different processor frequencies

This invention describes how to avoid data loss due to limited buffer size during continuous tracing of high frequency events such as branches. Buffer data loss is adaptively avoided by either temporarily patching an instruction with a jump to itself or by using delay loops with an adaptive number of iterations during exception handling in which the trace event is written to the buffer.

Adaptive prevention of data loss during continuous event tracing with limited buffer size

A computer implemented method, apparatus, and computer program product for executing instructions. A determination is made as to whether a processor executing a plurality of instructions is in an instrumentation mode. The processor has a normal set of resources and an alternate set of resources in which the alternate set of resources is associated with the instrumentation mode. When a determination is made that the processor is in the instrumentation mode, the processor executes instrumentation instructions in the plurality of instructions using the alternate set of resources and executes all other instructions in the plurality of instructions using the normal set of resources.

Method and apparatus for executing instrumentation code within alternative processor resources

A computer implemented method, apparatus, and computer usable medium for gathering performance related data in a multiprocessing environment. Instrumentation code is executed on a processor that minimizes the distortion to the processor resources used to execute the program to be profiled. Data is written by the instrumentation code to a shared memory in response to an event occurring during execution of the program. The data is generated during execution of the program on the processor and the instrumentation code uses shared memory to convey the data to a profiling application running on a set of profiling processors. The data is collected by the set of profiling processors in the shared memory written by the instrumentation code.

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Austin, TX, United States of America

Enio Manuel Pineda