OS X Mavericks: What is "Timer Coalescing" And More
There was plenty discussed and unveiled at yesterday's WWDC, particularly with the new OS releases. More broadly, Apple were touting their latest battery life capabilities, a result of several new innovative features. First on the list is Intel's latest "Haswell" CPU systems, which provide reasonable energy efficiency increases. Because the chips run at lower wattages, they are simply more efficient when it comes to their battery-burden. Beyond this, Apple also unveiled a few other clever tricks, here's a run down and explanation of the key features.
Timer Coalescing: will only be in operation when the device is running on battery power, as its benefits are purely for energy efficiency. In essence, because the timers of applications can be sending requests to the CPU without any synchronization, it can cause the CPU to be running constantly at varying levels. This new software feature means that the applications can synchronize their timers and send requests to the CPU that enable it to operate with spikes and then idle at the lowest possible power consumption levels otherwise. This means that active applications will drain less power overall. Put simply, that is really all Timer Coalescing does. The below graph, courtesy of "Ars Technica" visualizes this feature.
Memory Compression is one of the principle components responsible for this improved performance. Compressed memory compacts recently used items to about half of their original size, and then simply decompresses them when they are needed again. Similar to how you can Zip and Unzip large files to make them more portable, this technique makes it easier for the computer to "move" files around and access them more efficiently. Instead of moving information to and from the disk, Apple considers that the compression cycle is more energy efficient and faster. (Even with a solid-state drive.) What is especially exciting is that by installing Mavericks on older machines, even more remarkable performance increases might be made. In a nutshell, this feature should free up some memory, improve speed, and decrease the overall wear-and-tear on your disk.
App Nap is another feature released, which effectively rations out CPU power more carefully to prevent inactive applications from absorbing too much power unnecessarily. Standard settings will intensely curtail CPU resources to applications that are not visible, or are not playing content. The settings can be altered and developers will be able to override the specific features however. The goal with this is to produce faster responsiveness for active applications, and less system-drain for inactive programs. In concert with this feature, Mavericks will also decrease the UNIX priority for background applications to ration CPU more stringently. This should be of benefit in terms of both speed and energy performance.
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All in all, Apple are being pretty clever at combining updates and innovations in both software and hardware to produce machines that are more efficient and more high performance. These features are all admirable, as there is a clear goal of maximizing available performance, a focus on achieving peak efficiency. Even if all of this simply results in booting up "Gangnam Style" on Youtube 40% quicker, so be it, that's still a good thing (I think!)
