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2012-01-16
, 13:48
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Posts: 191 |
Thanked: 415 times |
Joined on Jan 2012
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#12
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I would ask you to repeat the tests with pre50 build or with my latest v49 build in KP thread, SmartReflex for frequencies above 600 in KP49(the one in devel repo) is a kind of "first iteration". In latest patch I sent to pali (and which is in KP pre50) SR should behave better for OC frequencies(hopefully).
EDIT:
AIUI mplayer uses SW decoding, so data when DSP is involved is still missing. You should use stock player for that.
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2012-01-16
, 14:12
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Posts: 3,074 |
Thanked: 12,964 times |
Joined on Mar 2010
@ Sofia,Bulgaria
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#13
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'dsp' to 'default' is 805 to 600, or about 34% increase in frequency for a 10% power penalty, right?
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2012-01-16
, 16:29
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Posts: 3,617 |
Thanked: 2,412 times |
Joined on Nov 2009
@ Cambridge, UK
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#14
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2012-01-17
, 18:27
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Posts: 191 |
Thanked: 415 times |
Joined on Jan 2012
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#15
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OC should save power on high-load time-independent processes. If it can complete the process in a shorter time, then it can switch back to a lower power mode quicker. Playing a video is time-dependent though, so unless it can switch down for micro-seconds between frames (which may depend on the CPU governor) then it'll be running at full power for the entire time. Something like a compression job should allow the CPU to complete the task faster and switch back to low power mode quicker (providing it's not I/O bound anyway).
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2012-01-17
, 18:57
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Posts: 1,455 |
Thanked: 3,309 times |
Joined on Dec 2009
@ Rochester, NY
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#16
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Just imagine how different things would have been if such careful investigation had been undertaken when overclocking was first proposed; instead the powers that be chose to focus on bogus and hysterical scare stories.
dd -count 20000 -if=/dev/random | gzip -9 >/dev/null
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2012-01-17
, 19:34
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Posts: 1,455 |
Thanked: 3,309 times |
Joined on Dec 2009
@ Rochester, NY
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#17
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Playing a video is time-dependent though, so unless it can switch down for micro-seconds between frames (which may depend on the CPU governor) then it'll be running at full power for the entire time.
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2012-01-17
, 20:03
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Posts: 191 |
Thanked: 415 times |
Joined on Jan 2012
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#18
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Whoh there! Hold on a second. One quick question: How long did each test run for? And how much longer did the under-clocked test run? Also, where you writing said file to flash? If so, you're not testing MPU, you're testing flash write, since that's by far more expensive than the MPU running. And if you're not counting the extra idle time the system has after the faster version is done, it's not exactly a fair test. the whole concept of race to idle means you need to count that idle time as part of the equation.
for i in $(seq 1 9000); do md5sum sintel-trailer-480.mp4; done > /dev/null
All other things being equal, I'm willing to bet that a device clocked at 500-900 will have much better savings than one clocked at 250-600 (from my own experience).
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2012-01-17
, 21:45
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Posts: 3 |
Thanked: 2 times |
Joined on Nov 2011
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#19
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2012-01-18
, 13:27
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Posts: 37 |
Thanked: 18 times |
Joined on Jun 2011
@ /dev/null
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#20
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Congratulations on your work. Great improvement on the N900.
My experience with kp49 has been great.
I use DSP profile adjusting minimum clock speed to 500 MHz and maximum to 950 MHz. Always. Using less than 500 seems to cause breaks on audio playback of certain files (The Economist Podcast is one of them). The minimum frequency seems to change little the current consumption when the phone is on standby.
Battery and speed patch seem to interfere with kp49 use of smart reflex. I found I had to remove them.
Now, I get almost 24 hours of standby with skype conected on WiFi (my minimum use). Apart from eventual bursts of current comsumption (100 to 280 mA), my current keeps down between 18 and 50 mA.
I guess the greatest benefit of SR is when you are NOT using N900's features (stand by).
Great job!
EDIT:
AIUI mplayer uses SW decoding, so data when DSP is involved is still missing. You should use stock player for that.
EDIT2:
Well, results are actually not so bad, for about 13.5% higher frequency we have 10% more battery drain. And higher drain seems somehow expected as playng a movie through CPU most probably keeps it awake all the time.
Last edited by freemangordon; 2012-01-16 at 13:16.