Overclock N800 with new OS2008?
I have just tested the CPU of N800 (New beta OS2008),
run X terminal ,then ~ $ cat /proc/cpuinfo result: Processor : ARMv6-compatible Processor rev 2 (v6l) BogoMIPS : 388.54 Features : swp half thumb fastmult vfp edsp java CPU implementer : 0x41 CPU architecture: 6TEJ CPU variant : 0x0 CPU part : 0xb36 CPU revision : 2 Cache type : write-back ... From the result ,we know the frequency of CPU at OS2008 is 388.54MHz,it's higher then OS2007! Then I want to test it under heavy load.I play the "Nokia-N810.avi" video with default Media Player ,simultaneity -run the test: ~ $ cat /proc/cpuinfo Processor : ARMv6-compatible Processor rev 2 (v6l) BogoMIPS : 320.37 Features : swp half thumb fastmult vfp edsp java CPU implementer : 0x41 CPU architecture: 6TEJ CPU variant : 0x0 CPU part : 0xb36 CPU revision : 2 Cache type : write-back ... It become 320.37, Not 400MHz,Why? |
Re: Overclock N800 with new OS2008?
This has all be covered in several posts already. OS2008 does increase max CPU speed to 400MHz. However IIRC the DSP runs at it's max rate when the CPU is at 330MHz.
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Re: Overclock N800 with new OS2008?
Bogomips != frequency. 388 equals about 400MHz with this CPU and operating system. The N800 will change the frequency at will, depending on the load (and sometimes it'll drop down the voltage too, all to save on battery). It also has to go down to a lower frequency when it's using certain DSP (digital signal processor) operations, because the DSP must run at a frequency which is linked to the CPU frequency. If the CPU frequency is 400MHz then the DSP frequency must be reduced instead of increased, or it would go above its design limit. Nokia had this table in a presentation posted here and elsewhere:
Code:
ARM DSP |
Re: Overclock N800 with new OS2008?
It would be interesting to know what percentage of the DSP decoding mp3 takes (there are some figures returned in the sysfs, but I've never really looked at them. Now's the time) and how the speed limit is applied when using the DSP. If the DSP is fast enough at 133MHz, then the ARM could be run at full speed for the video decoding.
I also remember Igor talking about an unsupported rate with both DSP at full speed and the ARM at (or perhaps) above full speed. Was that a post on itt or the mailing list/irc? |
Re: Overclock N800 with new OS2008?
Well IIRC there is actually hardware support for MP3 decoding, but other supported audio formats (AAC, etc) would be a different story.
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Re: Overclock N800 with new OS2008?
Quote:
quote: "The most interesting change would probably be to run the system at the (unsupported) configuration ARM@400, DSP@266, which would make it possible to avoid the current weird op selection mechanism." |
Re: Overclock N800 with new OS2008?
Quote:
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Re: Overclock N800 with new OS2008?
with the full release of os2008 did anyone notice changes in the cpu load?
i think it is a little slower that it was on the beta os. i run some progs and tested the cpuload when i am running nothing (not even desktop applets) BogoMIPS : 160.68 when i run xmms or watch a video BogoMIPS : 388.54 |
Re: Overclock N800 with new OS2008?
Quote:
Accordin to Igor dsp needs to run at 220MHz because Quote:
So for 'normal' use cases like playing mp3 the dsp can run at 133MHZ and ARM core at full 400Mhz. For more details check "Frequencies scaling with OS2008" scattered threads in January archive of maemo-developers. As for overclocking dsp to 266MHz check the same post linked above. It is a bit dangerous and may need cold flashing when something goes really wrong. |
Re: Overclock N800 with new OS2008?
The kernel is here http://fanoush.wz.cz/maemo/kernel-2....-dsp133.tar.gz
It has sd/mmc high speed 48MHz mode enabled, extended brightness control, crypto API enabled just like any of my kernels. In addition, with this one dsp/cpu plays audio at 133/400 instead of 220/330. |
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