Again, another session that is an incredible subject:
“Designing Power-Aware Windows "Longhorn" Applications
Track: Mobile PC and Devices Code: MBL304
Room: Room 402AB Time Slot: Tue, October 28 12:30 PM-1:45 PM
Speakers: Allen Marshall, David Switzer
As anywhere, anytime wireless network access becomes reality, customers are starting to expect their mobile PCs to act more and more like cell phones. With over a billion cellular phones in use worldwide, it's hard to argue with the opportunity presented by making mobile PCs run for days without needing to be plugged in. To take advantage of this opportunity, it's critical for Windows applications to register for and respond appropriately to power status notifications from the operating system. Learn about the power management support today and tomorrow and see how to use it in your applications to enhance the user's experience and save power.”
I have the unique ability to interact with top researchers in the field, who are major contributors to Intel. One of the huge things they are working on is power. Everyone thought that the problem was that we didn’t have enough power, right? I wish my laptop lasted all day, but it doesn’t. On the contrary, we are faced with increasing power consumption demands. First of all, everyone should know that transistors leak. It is just natural tendency, and there’s not much we can do about it. “And that's the problem. If current trends continue, you would have a device with 425 million transistors in 2005 and a processor with 1.8 billion transistors by 2010, said Pat Gelsinger, Intel Corp.'s vice president and chief technology officer. You'd also have a heat generator with the intensity of a nuclear reactor, he said.” Can you imagine? So the problem comes down to this: how do we keep increasing clock speed, while keeping power under manageable levels. “Even using 0.1-micron technology, Gelsinger envisions a 425-million-transistor die, 40 mm per side, which, clocked at 30 GHz, would dissipate 3,000 to 5,000 watts. In terms of power density, its heat would be close to that of a rocket nozzle, Gelsinger said. Conventional methods of using lead frames and specialized heat sinks will not cope with the power density. "Going forward, I don't think we know how to cool a 5000-watt processor," Gelsinger said. "We can't keep building these things with ever-increasing power budgets," he lamented.” “The current-generation Pentium, produced in 0.125-micron CMOS, dissipates about 66 watts. The same device in a 0.1-micron process—clocked at GHz rates—would dissipate, say, 200 watts. With a 1-V supply, the current consumption would be on the order of 200 amps.”
If you look at thermal plots for running microprocessors, you will see intense levels in one particular place, which contributes to the power density. Keep in mind that this area may change from application to application, but not much. So, what about the heat sink?
“The disparity between maximum power and typical power consumed presents a particularly difficult problem to the system designer. The system must be designed to ensure that the processor does not exceed the maximum specified operating temperature, even when it is dissipating the maximum power. While designing an elaborate heat sink, or forcing more air through the system can usually meet this constraint, there is usually significant cost associated with more elaborate solutions and environmental regulations that limit system (fan) noise.”
You may ask how do we solve all of these problems, and I know for sure these things would hit home if you could see all of the graphs and exponential curves. Why can’t we take the little ARM processors that sell for about $8 and put 10 of those in a computer? This would be approximately the equivalent of the fastest Intel Chip. Compare it, $80, to about $300-$400. Secondly, it would only consume about 20% of the power for the Intel chip. What’s wrong with this? Nothing, the problem is that we don’t have software that can let us do this yet.
Have you ever heard your fans on your laptop turn on and off? If you put your head next to them, they almost sound like Microwaves. I know a couple of people who actually have 2 fans! What is going on here? Well, the processor is conserving power by adjusting the level of the fan. So when peak demand for the Microprocessor is needed, those things are running full blast. This is the exact same principal that research tells us that we need to do with the operating system. If we embed heat sensors on various parts of the chip, the OS can actually throttle Microprocessor spikes and minimize the heat throw-off. Run a search on the internet for pictures of Microprocessors on fire. In the Intel and AMD labs, they probably have many.
I see that longhorn is on the right track. Of course, they are probably working closely with Intel and AMD, among others.