computer science

PowerTOP

PowerTOP is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand PowerTOP rather than just read about it. In short: PowerTOP is a software utility designed to measure, explain and minimise a computer's electrical power consumption. It was released by Intel in 2007 under the GPLv2 license.

Key takeaways

PowerTOP belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect PowerTOP to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PowerTOP from memory before moving on to harder problems.

Reference excerpt

PowerTOP is a software utility designed to measure, explain and minimise a computer's electrical power consumption. It was released by Intel in 2007 under the GPLv2 license. It works for Intel, AMD, ARM and UltraSPARC processors. PowerTOP analyzes the programs, device drivers, and kernel options running on a computer based on the Linux and Solaris operating systems, and estimates the power consumption resulting from their use. This information may be used to pinpoint software that results in excessive power use. This is particularly useful for laptop computer users who wish to prolong battery life, and data center operators, for whom electrical and cooling costs are a major expenditure.

Usage The original focus was on CPU sleep states, and showing the programs or drivers responsible for "wakeups" which prevent CPUs entering sleep states. A database of known problems automatically provides more user friendly "tips" for specific sources of wakeups. However, it also shows information on CPU frequency scaling. Over time the database has been expanded to include tips on a wide range of power consumption issues.

Project activity The latest release of PowerTOP (version 2.15) was made public on September 29, 2022. The project is hosted on GitHub.

Illustrations

Worked examples

Example 1 — a first encounter with PowerTOP

Start with the simplest possible case. Write down what PowerTOP claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to PowerTOP before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about PowerTOP ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of PowerTOP

In research: PowerTOP appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses PowerTOP in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: PowerTOP is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computers and the environment, Linux process- and task-management-related software, so understanding it makes those chapters shorter.
In everyday life: Look for PowerTOP outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study PowerTOP in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PowerTOP means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain PowerTOP out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PowerTOP in simple terms?

PowerTOP is a software utility designed to measure, explain and minimise a computer's electrical power consumption. It was released by Intel in 2007 under the GPLv2 license.

Why does PowerTOP matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study PowerTOP?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on PowerTOP.