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> Wierd New Kernel Options, power saving?
post Apr 19 2007, 08:26 PM
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THere have been a couple of new kernel options that have been introduced latley and i am wondering if any one else knows about them or wants to comment

the first is the "tickless kernel" which does away with "switch tasks every 1000hz" and changes it to "go to sleep until somthing needs the cpu. as we all know doing a hlt or simmilar saves power and it allows for great power savings when put together with other things

the other new one in the next kernel is compleatly fair queing (http://kerneltrap.org/node/8059), sounds intresting to me but from what i can see this will play very nicly with the above tickless kernel. the advantages of this squedular is better responsivness, faster and less relinace on ticks and jiffies (i belive it uses nano second tracking of execution time)

i should mention laptop mode here for compleatness, its been around for awhile but afaik it is very rarely enabled. what it does is only spin up the hard drive when somthing needs to be read OR a ceritn amount of time has elapsed. it stores all the writes and writes them together to help avoid the "power dump" on hard drive spin up and makes the drive idle longer

one of the more obvios ones is cpufreq scaling which explains its self, combined this with policies (cpufreqd anyone, powernowd or others dont really have the same featureset as it can ramp up the speed when you launch mplayer rather on the load as to avoid ossiclations where you go from 100% to 75% and repeat

well those are some of the options, now for the question. has anyone done some power testing with diffrent kernel options? i blew the power supply on my last Z (about to get a new one) but it still works so i was planning to hook up a multimeter with datalogging via rs232 and do some automated powertesting with the dead unit.

any intrest in doing so? what do you want tested. in an ideal world i would love to see what an arch optimised vs processor optimised kernel/userspace does and EABI vs the normal stuff

i dont belive it would be too hard to set it up so the Z is permanttly net connected as well for a dev enviroment or to run your own power testing stuff however i see the timeframe on that one bieng about 2 months

i am aming to punch up the idle load run time by at least 3 hours and the mp3 playing load by 1 hour. moive playback i am aiming for 30 minutes however this one is hard to quanitfy as there are many diffrent moive types that are optimised diffrently for the Z (ie divx, mpeg4, xvid, h263, not to mention container formats)
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