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Round Robin Scheduling Not Power-Efficient
Via_Patrino writes "While having to distribute load between several servers, round robin, or any other technique that balances load equally, is the most common approach because of its simplicity. But a recent study shows that trying to accumulate load on some servers can improve energy efficiency because the other servers will be mostly unused during off-peak periods and then able to make better use of power saving methods. Specially, where load involves lots of concurrent power-consuming TCP connections, which was the case in the study, a new load-balancing algorithm resulted in an overall 30% power savings. Here's the paper (PDF)."
This problem shows up in many places.
technical writing / development
Operators of multiple steam boilers have been dealing with this problem for a century. The number of boilers fired up is adjusted with demand, with the need for some demand prediction because it takes time to get steam up. This was done manually for decades; now it's often automated.
The same thing applies to multiple HVAC compressors. Usually there's a long-term round-robin switch so that the order of compressor start is rotated on a daily or weekly basis to equalize wear.
More and more, IT is becoming like stationary engineering.
We've been sacrificing computing power for efficiency for years. New Server CPUs tout thier energy savings atleast as much, and quite often more than they tout their computational power. As electricity gets more expensive and data centers continue to grow this trend can only continue; it's simply too expensive to a warehouse full of server racks unless you focus on efficiency.
I'm waiting for the first company to put a data center a few hundred feet under water, where the water temp is low. You'd be surrounded by the worlds biggest heat sink. The environmentalists would have a hissy fit but that's never stopped industry before, and of course you could argue that you are saving electricty on cooling.
I believe your calculations are wrong. It's understandable, though, since soccer parenting is a fairly unique branch of mathematics.
First off, you're assuming a standard car with 1 adult driver and 4 passengers; instead, you should be using an SUV with a capacity of 6-8, including driver.
(Result: 4-5 vehicles)
Next, you have to consider that not all parents will attend every game. The primary reason that soccer moms drive SUVs is that they must occasionally transport several of their child's teammates to a game (or, worse, to practice!) when their turn comes up in the rotation. Therefore, you only need enough SUVs to cover the number of child passengers, and the number of adults will follow.
(Result: 2-3 vehicles)
However, you might recall that the other reason that soccer moms drive SUVs is that they often have additional children that have not yet reach sports playing age, and must be transported along with the parent, in a car seat (which, in the case of a standard car, would reduce passenger capacity by at least 20% by rendering the back center seat useless.) Assume that approximately 1 in 3 soccer moms have an additional child to transport, and the child adds to the overall passenger count.
(Result: 3-4 vehicles)
Finally, realizing that the overloaded schedule and priorities of child + parent create scheduling conflicts, it is impossible to get optimal performance. At least 1 child per SUV will be late, leaving a seat empty and requiring another parent with car to tranport them.
(Result: 6-8 vehicles)
The result is a range of possible values, but your initial calculation of 6 vehicles is optimistic at best.
Did I say overlords? I meant protectors.