Intel's Game Changer: One Size Fits All Haswell

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In Windows 7, the maximum amount of time hardware was allowed to stay in idle mode while awake was 15.6 milliseconds. One of Microsoft's design imperatives with the new operating system was to allow for longer idle periods, group timer updates and requests together, and give the system room to go to sleep when it didn't actually need to be powered up. The two slides below summarize W8's improvements (Intel characterizes them as better hygiene) at both the CPU and network/disk level.

 
Click for high res.

The next slide shows Windows 7's default activity, its activity when scheduled tasks are aligned with processor active cycles, and Windows 8's default scheduling.



In the Windows 7 comparisons, the black tick marks are 15.6ms apart. There are 7 ticks, for a total of 109.2 milliseconds, or roughly a tenth of a second. With default scheduling, the CPU only idles a full 15.6ms twice. From the first tick to the second, the chip drops into idle ~40.2% of the time. Aligning poll timers and grouping deferrable requests together under Windows 7 significantly improves the situation; the CPU spends 87% of its 15.6ms window in idle mode between ticks 1&2.

Windows 8 jettisons the system timer altogether, discourages poll timing, and aligns activity more stringently. As a result, the system spends a much higher amount of time in idle or low-power mode, even dropping into a CPU power-off state at one point. Because we're still talking about milliseconds, the end user hasn't even noticed the difference -- but the device's battery will.
 

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You're right Joel, power considerations are going to steer the market of the future.

I wonder if the competition has any Rabbits in their hats?

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Haswell is looking to be a killer chip for sure.

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It was very interesting to read about new processor from Intel. I think it is good to reduce the power of CPU. I am looking forward to read next gen Intel CPU for desktop and next Extreme Edition Series from Intel

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Realneil,

Not unless they can break the laws of physics.

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This intel guy holding the CPU looks like he's passing something righteous!

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I don't see where any changes to the laws of physics are necessary to make this happen. They are simply turning off circuitry when it's not being used and providing different levels of performance to meet varying demands. Balls out the chips still gonna suck power and dissipate heat, but when it's doing lighter tasks, it can turn parts of itself off or slow them way down that aren't being used and save power. The complexity of such circuits relative to the rest of the processor is probably fairly trivial. It is sad that they are focusing on one OS vendor, Microsoft, because Windows-8 frankly blows. I'd much rather see them do a good job of documenting so that Mac, Linux, BSD, and other OS's can ALL benefit from these capabilities.

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Pushing Haswell down to 10W is an even greater achievement, but hitting these targets requires a great deal of collaboration and cooperation.

I work for Intel and they got it to 7W not 10. This is also public knowledge.

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I'm writing a paper on this for my "Organizational Report Writing" class. The chip seems stellar.

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This is all pretty impressive.

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It sounds like although its power consumption is being decreased by a slight amount, the number Intel is reporting is correlated with what the CPU is doing while still being "on"

It's good to see some improvements and that power consumption is dropping when it's in minimal use or idle but what's really important is finding a way to decrease power consumption in heavy top side loads since most people buy computers to use them, not try and keep them to minimal or idle use. 

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