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Actually, It Is Easy Being Green

Comments(0)Filed under: Low power , Logic Design, green, prius, palladium, dpa

Ok, I’ll admit it, I’m a bit of a leadfoot.  I like to go fast, especially off stop lights.  Maybe it is the competitive streak in me, but I love to be the first off a light.  Or maybe it is just me showing the BMW drivers that my Hyundai can go just as fast.


I also do a lot of traveling, and so end up in a lot of rental cars.  Hertz might cringe at this, but is there anything better than winding up a rental car?  Now before anyone yells at me, I’ve got a stellar driving record (touch wood).  But there’s something about a new rental car and a light turning green that turns me into Mario Andretti.


On my last trip to San Jose, I hopped off the rental car bus (aside – is there another airport as, um, messed up as San Jose??).  And found to my surprise that they had given me a Prius.  Ok, why not?  One advantage of traveling is you get to try different cars.  I still get a smile on my face when I recall the cherry red convertible T-Bird I once got.  I’d give the Prius a whirl.  Could be fun.  Or maybe I could figure out why the hype.


Now the thing about a Prius (forgive me if you know this) is that it has a big screen on the dashboard showing instantaneous mileage.  So you can see at any moment in time exactly how much energy you’re consuming.  And you can see the mileage over time – how are you doing during the trip.  Pretty cool idea.


So here’s what happened.  In a strange video game kind of way, I started to try to maximize the instantaneous mileage.  I found that I could get better results if I didn’t blow off the light.  If I coasted up to the light, the same results – 99MPG.  I found myself getting irritated when the gas engine turned on, and the mileage dipped.  In short, I started driving responsibly, all because of this dumb screen showing me how I was saving or burning energy.


Nirvana came to me on the third day, when I got the car up to the right speed, and then maintained that with a light touch on the pedal.  The result – the car was only being powered by the battery.  I ended up with 99MPG for about 5 minutes – YES!!  Just by getting feedback, I changed from a leadfoot to maintaining the perfect balance.


Ok, there is a point to this (I’m imagining you saying, “Get on with it!!!”).  As my colleague Jack Erickson has pointed out (here), getting feedback on energy use is the first step to doing something about it.  And there are finally some EDA tools to help accomplish this.  One that is particularly interesting is Dynamic Power Analysis with the Palladium system.  DPA allows you to measure the power during real operation, including running software applications.  The power engine is based on the power analysis built into RTL Compiler, so it is production proven.  DPA was just named Product of the Month by Portable Design Magazine.


The nice thing about this is that there’s only a minor modification in methodology to get the feedback.  So if a design team is using Palladium to validate system software or design operation, there’s no real reason why not to perform this power analysis.  The same is true of other EDA power analysis and optimization engines – they’re largely there, waiting for use.  Using these systems, you’ll measure the power of your design and system.  And measurement is the first stage to doing something – balancing the software load, implementing shutoff or MSV, implementing clock gating – something.  If you use these tools, it really could be easy to be green.



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