CPU time

Summary

CPU time (or process time) is the amount of time for which a central processing unit (CPU) was used for processing instructions of a computer program or operating system, as opposed to elapsed time, which includes for example, waiting for input/output (I/O) operations or entering low-power (idle) mode. The CPU time is measured in clock ticks or seconds. Often, it is useful to measure CPU time as a percentage of the CPU's capacity, which is called the CPU usage. CPU time and CPU usage have two main uses. The CPU time is used to quantify the overall empirical efficiency of two functionally identical algorithms. For example any sorting algorithm takes an unsorted list and returns a sorted list, and will do so in a deterministic number of steps based for a given input list. However a bubble sort and a merge sort have different running time complexity such that merge sort tends to complete in fewer steps. Without any knowledge of the workings of either algorithm a greater CPU time of bub

Official source

https://en.wikipedia.org/wiki/CPU_time

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Continuous Bytecode Instruction Counting for CPU Consumption Estimation

Andrea Camesi

As an execution platform, the Java Virtual Machine (JVM) provides many benefits in terms of portability and security. However, this advantage turns into an obstacle when it comes to determining the computing resources (CPU, memory) a program will require to run properly in a given environment. In this paper, we build on the Java Resource Accounting Framework, Second Edition (J-RAF2), to investigate the use of bytecode instruction counting (BIC) as an estimation of real CPU consumption. We show that for all of the tested platforms there is a stable, application-specific ratio of bytecodes per unit of CPU time – the experimental bytecode rate (BRexp) – that can be used as a basis for translating a BIC value into the corresponding CPU consumption.

IEEE Computer Society Press2006

Towards CPU Load Prediction for Java Bytecode

Andrea Camesi

This paper studies the use of bytecode instruction counting (BIC) to estimate the CPU load due to the execution of Java programs in different environments. BIC is the basis of the J-RAF2 framework to monitor and control the resource consumption of Java code, and, more recently, is also used in another tool to profile Java code. The advantage of BIC resides in its complete portability, from mainframes to embedded devices, and in the reproducibility of the reported bytecode counts. However, BIC and CPU time are not strictly equivalent units of measurement, therefore we need to study the relationships which exist between them. This paper shows, based on the SPEC JVM98 and SPEC JBB2000 benchmarks, that for each platform there exists a stable, application-specific ratio of bytecodes per unit of CPU time that can be used for translating a BIC value into the corresponding CPU load. Possible extensions of this property are also discussed.

2005

Continuous Bytecode Instruction Counting for CPU Consumption Estimation

Andrea Camesi

As an execution platform, the Java Virtual Machine (JVM) provides many benefits in terms of portability and security. However, this advantage turns into an obstacle when it comes to determining the computing resources (CPU, memory) a program will require to run properly in a given environment. In this paper, we build on the Java Resource Accounting Framework, Second Edition (J-RAF2), to investigate the use of bytecode instruction counting (BIC) as an estimation of real CPU consumption. We show that for all of the tested platforms there is a stable, application-specific ratio of bytecodes per unit of CPU time – the bytecode rate (BR) – that can be used for translating a BIC value into the corresponding CPU consumption. Possible extensions and applications of this property are discussed.

2006