• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
KingofNoobs

Sleep and Electricity

2 posts in this topic

Hello,

I was wondering what sleep() really does. I mean, how does a CPU core go to "sleep?" Electricity always moves by definition at a fixed speed in a given medium, so we can't just "stop" the signal and wait for something to happen. I imagined that the CPU was just one big circuit and that the electricity always flows but the circuit may cut off a loop or the circuit not to be actualized until a voltage from outside the system (i.e. the graphics device) re-activates it. Is this correct and can I understand my system to be doing this when I use the sleep() function, or am I just passing control off to an operating system call that will not recall my code for a given amount of time, at which point my code resumes from the line following sleep()? If the latter is the case, then how can an operating system sleep()? Would that be possible? Can an operating system put an entire core to sleep() but not other cores for power saving reasons or to reduce necessary fan noise? Could a game have the same level of cpu sleep()ing individual cores? To summarize, is sleep() an system call or does it act directly on the hardware CPU? And can operating systems sleep() as a power-saving or noise-reducing feature and can games or other applications do the same?

Thanks.

- Dave Ottley
0

Share this post


Link to post
Share on other sites
[quote name='KingofNoobs' timestamp='1353361539' post='5002452']
Electricity always moves by definition at a fixed speed in a given medium, so we can't just "stop" the signal and wait for something to happen. I imagined that the CPU was just one big circuit and that the electricity always flows but the circuit may cut off a loop or the circuit not to be actualized until a voltage from outside the system (i.e. the graphics device) re-activates it. [/quote]
You seem to be confused a little about how circuitry works so here's a quick crash course.

Consider first a diode ( http://en.wikipedia.org/wiki/Diode ). A diode's behavior depends upon the source voltage. At low voltages a diode will consume a very low amount of electricity (an ideal diode consumes NO electricity because at infinite resistance no electricity can flow). At high voltage the diode does consume electricity (at which point the diode can be modeled like a normal resistor). Diodes aren't really used in CPUs though, it's just a simpler concept than...

The transistor ( http://en.wikipedia.org/wiki/Transistor ). You can imagine a transistor as behaving like a dam. A dam has a reservoir that's normally filled with water. The dam doesn't have to let any of the water out of the reservoir, a gate must be open first. If the gate is opened then if there's any water at the source of the reservoir then it can drain out. No water at the source and no water flows out the drain, regardless of whether the gate is open.

A transistor works the same way. A transistor has a 'gate', a 'source', and a 'drain'. In this case the gate is opened or closed depending on whether there's voltage there above a certain threshold. If any electricity is present at the source, it can flow through the drain when the gate is open. Like a diode, if the gate is closed then there shouldn't be any electricity usage. Of course also like a diode that's for an 'ideal' transistor'. A real transistor will leak some current, even with a closed gate. So if you shut off enough transistors for some reason this would result in much less current (and this power) being consumed.

Many processors support a standby mode where the CPU is made almost entirely inactive, until an interrupt is triggered awakening the processor. That said, I'm not sure if this processor feature is necessarily *used* by Microsoft in their OS. If it is, it's definitely not going to be used when a random program calls 'sleep', but when the OS decides to go standby mode at which time pretty much nothing is going to happen until the OS wakes up again.

And of course, what frob said about reducing clock frequency.
2

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0