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The reason for the focus on CPU time is that it has the larger impact on battery life.
by omnimike 5y ago
The reason for the focus on CPU time is that it has the larger impact on battery life.
- tasn 5y agoYou'd be surprised (I was), but high memory usage is also a power drain.
- tehbeard 5y agoSo is the screen, keyboard, WiFi/ethernet adapter... Do you have any graphs/charts/tables to substantiate the claim that high memory usage is power hungry enough to be optimized for vs CPU?
- dspillett 5y agoIt isn't a surprise when you consider indirect power costs: CPU use filling that memory and reading it back later, extra IO because the memory consumed is not available for caching purposes (or worse because paging out to more power-expensive storage is happening), and so forth. It is like when people say page fragmentation in SQL Server isn't important any more because random access is so fast due to SSDs and other IO subsystem improvements – pages are held in RAM in the storage format so if they are only ⅔ filled you are wasting ⅓ of the allocated memory which can have significant performance effects if your common working set is not smaller than the memory available. Though in fairness, I would agree that this issue is usually quite far down the list of things that need addressing in poorly performing database & applications.
- IshKebab 5y agoThat sounds unlikely since DRAM is all refreshed constantly regardless of whether or not it is being used. Perhaps you meant storing and fetching from memory lots impacts battery life?
- kalleboo 5y agoWith higher memory usage you have less free memory for caching so you hit the disk/SSD more often. If it gets too high you start swapping which is really bad.