Linux support for ARM big.LITTLE [LWN.net]

Linux support for ARM big.LITTLE

Posted Feb 18, 2012 11:09 UTC (Sat) by khim (subscriber, #9252)
In reply to: Linux support for ARM big.LITTLE by dlang
Parent article: Linux support for ARM big.LITTLE

it doesn't matter if you are a 12 core Intel x86 monster, or a much smaller ARM chip.

Well, sure. But differences between interactive tasks and batch processing modes are acute. With batch processing you are optimizing time for the [relatively] long process. With interactive tasks you optimize work in your tiny 16ms timeslice. It makes no sense to produce result in 5ms (and pay for it) but if you spent 20ms then you are screwed.

Today the difference is not so acute because the most power-hungry part of the smartphone or tablet is LCD/OLED display. But if/when technologies like Mirasol will be adopted these decisions will suddenly start producing huge differences in the battery life.

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Linux support for ARM big.LITTLE

Posted Feb 18, 2012 11:58 UTC (Sat) by dlang (✭ supporter ✭, #313) [Link]

agreed, I'd love to have a passive LCD display netbook that was able to transparently sleep between keystrokes, but realistically we are a long way from that in terms of the hardware capabilities, and even further away from that in terms of being able to predict the future workloads correctly.

i don't think we are ever going to get away from having to make the choice between keeping things powered up to be able to be responsive, and powering things down aggressively to save power.

Linux support for ARM big.LITTLE

Posted Feb 20, 2012 12:17 UTC (Mon) by khim (subscriber, #9252) [Link]

Hardware is in labs already (and should reach the market in a few years), it's time to think about software side.

If we are talking about small tweaks then such hardware it not yet on the radar, but if we plan to create the whole new subsystem (task which will itself need two or three years to mature) then it must be considered.