Slashdot Mirror
Boosting Battery Life For RISC Processors
prostoalex writes "National Semiconductor and ARM Holdings will jointly develop the power management solution for RISC chips, that they estimate will improve battery life by 25-400%. The target date of the first sample product is Q2 2003." My old Tadpole laptop sure could have used this. I counted myself as lucky when I got a whole 45 minutes out of a battery.
I once had this link to research done on cpus, which are designed from the ground up to be VERY low power. Consider this: they saved power at the *gate* level!
Looking for people to chat about multicopters, coding, music. skype: gtsiros
When developing portable devices the most limiting factor today is not processing resources, memory or anything such. It is simply the power source.
Batteries of today are either too weak or too heavy. How ofter does one have to choose between a slim-line battery or an ultra-long life.
There have been many suggestions for competing technologies such as fuelcells, harvesting of motion energy and solar cells to mention a few. But still, they have proven to be too expensive, large or have some other problem (such as not being ready for production use yet). Hopefully these one of these, or any other, portable power sources will make it possible to carry real computing power without having to carry a heavy battery pack.
The solution today is to reduce the power usage. This can be done by shutting down parts of the clock trees in the CPUs, or by using Intel's PowerStep (i.e. two working speeds), or Transmetas's variable voltage and frequency technology, LongRun. As the article lacks technical details we can only guess about the techniques used behind the PowerWise solution. Also, the figures 25-75% efficiency gain is most probably measured under special conditions.
But, in order to avoid sounding too negative, it seems like the industry has realized the problem and are working for a solution. I feel that most of today's solutions (power saving) are just a cure for the symptoms (bad battery time), not for the cause (bad battery technology).
[BLOCKQUOTE]
According to the article:
Arm's Intelligent Energy Manager solution implements advanced algorithms to optimally balance processor workload and energy consumption, while maximizing system responsiveness to meet end-user performance expectations.
Transmeta's only claim to fame for their chips was using software to reduce power consumption, and it worked -- obviously, the Intelligent Energy Manager is just a ripoff of Transmeta's design. Linus should sue. [/BLOCKQUOTE]
Umm, no? These aren't CPUs used in computers and laptops.. these are used in handheld devices and embedded applications. I develop for ARM personally and the "algorithms" (note: they do not say software) is simply silicon embedded within the processor.. not software that runs on the processor itself.
As the poster mentioned, I doubt this will affect any laptops. I don't know of any that run off ARM cores.
http://www.arm.com/news/powerwise1111
They're basically targetting mobile phones and similar embedded systems like PDAs, because this is where ARM's main market share is at the moment. They say that they're looking at a more system-wide approach than is currently used, and they want to standardize the embedded software/hardware interface as part of this.
Also, note that "samples available Q2 2003" doesn't necessarily mean actual silicon. ARM doesn't make chips, they license their designs out to other companies which use them as a basis for an actual chip, so a "sample" quite likely means a software simulation. Actual devices which use this technology probably won't be around until 2004 at least.
"...that they estimate will improve battery life by 25-400%."
"Aw, people can come up with statistics to prove anything, Kent. Forty percent of all people know that."
-- Homer Simpson
I always thought RISC was inferior, that's why it lost out to CISC and went the way of the dodo. Who wants a reduced instruction set anyways? That's why it always lagged in the floating point benchmarks. I look forward to the day when our CISC processors are even better equipped - with an instruction for every conceivable operation.
?-|||-----x<*))))><
In line with the low-power paradigm gaining momentum within CPU designs, asynchronuous design is often mentioned in the context of battery life. Apparently, the ARM processor seems to be the (only) architecture used for innovative CPU designs.
Is this really the case, and if so, why? (Obviously CISC architectures are far too complicated to fine-tune in a drastic manner - other than building a Crusoe-like RISC chip and emulating the whole thing.)
Moreover, is power consumption (and not primarily performance) after all those years, going to be the criterium that's going to decide the RISC-CISC issue in favour of RISC?
In typical usage, there is a lot of time that the CPU is doing nothing. Design one that can take snoozes for as little as a millisecond at a time with insignificant latency and you can save a lot of power.
It is a simple question of market laws. The x86 architecture is the ruling class, therefore it gets most of the research money, and as a results has the fastest running processors.
When the ARM came out, it blowed the 386s (The top x86) and 68020's out of the water. We were talking 3-4 times faster. And when the ARM3 came out with it's cache, it really kicked 386 ass.
And remember the Alpha? Another RISC design that was way ahead the rest. The only one left is the PowerPC family, still holding on to the x86 juggernaut.
And programming the ARM was a bliss. 13 general purpose registers, the barrel shifter. (Do a arthimetic and shift in the same instruction) Conditonal branching... It was a real joy. The x86 assembler is what programmers do in hell.
J.
That's a nice range there.
Me: Hey Jim, we're throwing a party at your house tonight.
Jim: Great! How many people are gonna come? I need to know how much beer and hoes to pick up.
Me: Oh, plan on somewhere between 25 and 400.
As an old Acorn user who switched to Mac back in 1998, I can safely point you to this fact without appearing anti or pro Apple/IBM/ARM.
"ARM Company Milestones: ARM History - 1985 - Acorn Computer Group develops the world's first commercial RISC processor"
> My old Tadpole laptop sure could have used this.
I think the type of RISC processor might have something to do with the power consumption. ARM has always concentrated on frugal at the expense of fast.
Virtually serving coffee
You're giving statistics a bad (worse) name. Get your HomerStats straight, that was 14%.
"Internet. They have that on computers now?" -- HS
"Is the poop deck really what I think it is?" -- HS
You have to take the unknown value of x hours of battery consumption and apply it to the estimated average of the inverse expected increase in n.
.26ths of an hour increase in average expected battery life, or about 15 minutes. This is how you keep your job as an engineer... :)
x = 1/n(25%/400% - y) where y = battery life now (say 4 hours).
x = 1/n(16% - 4) [.16 - 4 = -3.84)
x = 1/n(-3.84)
1/3.84 = n
[this is a joke. this is only a joke. these numbers may be interperated by completing the square in a quadratic equation]
My cube. My friend. My solace. My prison.