Dilligaf
Posts: 283
Joined: Wed May 23, 2012 6:48 pm

Re: Overclocking

Thu Sep 27, 2012 7:20 pm

100/310/400 OV6 killed the partition real quick

QuietMike
Posts: 10
Joined: Fri Sep 07, 2012 11:18 pm

Re: Overclocking

Thu Sep 27, 2012 7:21 pm

I just read about the built in turbo modes, how do you activate those.
i have manually overclocked by editing the config.txt file before - are there new keys to use like 'turbo mode=?'

elatllat
Posts: 1337
Joined: Sat Dec 17, 2011 5:05 pm

Re: Overclocking

Thu Sep 27, 2012 7:24 pm

QuietMike wrote:I just read about the built in turbo modes, how do you activate those.
i have manually overclocked by editing the config.txt file before - are there new keys to use like 'turbo mode=?'

Code: Select all

raspi-config
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elatllat
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Re: Overclocking

Thu Sep 27, 2012 7:28 pm

dom wrote:...If it is related to high PLL frequency, then I'd expect
core_freq=300 => PLL frequency of 2.4G to be bad
core_freq=310 => PLL frequency of 1.86G to be good
Can anyone try that?
modest setting caused corruption.
modest+force_turbo=1 caused corruption.
modest+core_freq=250 seems to have worked.
modest+core_freq=310 caused corruption.
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dom
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Re: Overclocking

Thu Sep 27, 2012 7:30 pm

Dilligaf wrote:100/310/400 OV6 killed the partition real quick
Bah! Not the hoped for result.

elatllat
Posts: 1337
Joined: Sat Dec 17, 2011 5:05 pm

Re: Overclocking

Thu Sep 27, 2012 7:45 pm

So does that narrow it down to a per board core_freq limitation?
or is there something else to test?
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dom
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Re: Overclocking

Thu Sep 27, 2012 7:53 pm

elatllat wrote:So does that narrow it down to a per board core_freq limitation?
or is there something else to test?
There's some evidence for that, but to be sure, I'd like to hear from a number of people that this corrupts:
arm_freq=700
core_freq=310
sdram_freq=400
over_voltage=0
force_turbo=1

and this doesn't corrupt:
arm_freq=700
core_freq=275
sdram_freq=400
over_voltage=0
force_turbo=1

(possibly your values for core_freq values will be different).

Tompen
Posts: 20
Joined: Tue Aug 14, 2012 4:11 pm

Re: Overclocking

Thu Sep 27, 2012 7:59 pm

I have a easily reproducible data corruption situation. On latest OpenELEC commit 2c960890
This includes latest raspberry pi firmware b87bc42 + raspberry kernel patches.

Tested and no corruption:
current_limit_override=0x5A000020
over_voltage_sdram=5
over_voltage=4
force_turbo=1
arm_freq=1026
sdram_freq=500
initital_turbo=30

None of above config.txt settings cause (or helps) against corruption for me.
I have the following in cmdline.txt: sdhci-bcm2708.sync_after_dma=0

if I add
core_freq=300
to the above, I get data corruption.
Also core_freq=310 is corruption.

The test I do is:
wget a 88MB tar.bz2 file, then unpack.
tar -xvf always fails when core_freq=300 is enabled.
It always work when I have not changed core_freq.

The error is:
tar: bunzip error -5
tar: short read

I know my Rev1 pi is able to stable have the below settings:

current_limit_override=0x5A000020
over_voltage_sdram=5
over_voltage=4
force_turbo=1
arm_freq=1026
sdram_freq=500
core_freq=513
h264_freq=342
isp_freq=342
v3d_freq=342

because I have used it a couple of weeks ago.

At that time when it worked ok I was on firmware release (09 Sep commit a2747801):
Things that have changed for me since then:
switched xbian-->openelec
upgrade raspberry pi firmware
replaced SD-card

My current class10 SD-card is:
Image

This weekend I will stay on openelec and revert only the kernel and rpi firmware changes to my know-to-work release 09 Sep. Then go up from there and try to find the commit that cause corruption.

dom
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Location: Cambridge

Re: Overclocking

Thu Sep 27, 2012 8:10 pm

Tompen wrote:This weekend I will stay on openelec and revert only the kernel and rpi firmware changes to my know-to-work release 09 Sep. Then go up from there and try to find the commit that cause corruption.
Would be useful if you can find a start.elf/kernel.img combination that works okay, and if you can identify the version that breaks it.
(It is almost certainly start.elf that matters if it occurs with force_turbo=1)

There have been a number of tweaks to PLLs and one of those changes may result in success on fewer boards. Identifying the start.elf in github that made things worse would be useful.

milhouse
Posts: 641
Joined: Mon Jan 16, 2012 12:59 pm

Re: Overclocking

Thu Sep 27, 2012 8:22 pm

dom wrote: Does 750/250/+3 corrupt?
Does 750/250/0 corrupt?
Using a Transcend 8GB Class 10 card, neither of the above settings will trigger corruption in OpenELEC r12014 or Raspbian 2012-09-18 (rpi-update'd to the latest 339137 firmware).

On Raspbian, I apt-get upgraded the system, used rpi-update to update the firmware, booted the new firmware and played Quake while simultaneously creating a 500MB file ("dd if=/dev/zero of=./test.dat bs=1M count=500").

No problems at all with either of the above frequency/voltage settings.
dom wrote: Have you seen corruption in a stock raspbian image?
Yes.

On the same Raspbian system tested above (Transcend Class 10, Raspbian firmware updated to 339137 etc.) I bumped the core_freq by 5 and tested at +0 volts without a problem.

However, after I increased volts to +3, I was able to corrupt the filesystem (so at 750/255/+3).

To do so, I started Quake3, began loading a map (ie. not sat idle at the game menu) and in a separate window and as user pi I ran the dd file transfer (see above) while the map was still loading.

Catastrophic corruption of the ext4 partition quickly ensued (within about 15 seconds).

The system is now totally hosed with every command failing due to a seg fault.

I've repeated this setup a second time, and I've determined it's not even necessary to run Quake simultaneously with dd - I can corrupt the Raspbian partition just by running the dd transfer with settings of 750/255/+3 - log details of this second run are here (pastebin).


Note: Despite booting Raspbian/339137 with arm_freq=750, BogoMIPS in /proc/cpuinfo still displays as 697.95 - is this correct, do I have the correct kernel?

Code: Select all

[email protected] ~ $ cat /proc/cpuinfo
Processor       : ARMv6-compatible processor rev 7 (v6l)
BogoMIPS        : 697.95
Features        : swp half thumb fastmult vfp edsp java tls
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x0
CPU part        : 0xb76
CPU revision    : 7

Hardware        : BCM2708
Revision        : 1000002

Code: Select all

[email protected] ~ $ uname -a
Linux raspberrypi 3.2.27+ #174 PREEMPT Wed Sep 26 14:09:47 BST 2012 armv6l GNU/Linux
dom wrote: Do you have any other scdards you can try? Do you know anyone else with a Pi you can test on?
I imaged Raspbian 2012-09-18 to the SanDisk 4GB Class 2, and tested with 750/250/+0 and 750/250/+3 - it was fine. Upgraded to the latest firmware, tested Quake with simultaneous 500MB dd transfers from /dev/zero - again, no problems.

I then bumped the core frequency to 255, and experienced no problems with over_voltage=0.

However, with over_voltage=+3, I saw mmc/ext4 errors appear in /var/log/syslog while loading a map in Quake and performing a simultaneous dd transfer - you can see the log here (pastebin).

(The inclusion of Quake in this report may or may not be relevant as I subsequently determined it is possible to corrupt Raspbian without Quake and just dd)

The dd transfer did eventually complete after 12 minutes (it would normally take about 3 minutes [2.4MB/s] to transfer 500MB on this Class 2 card, with Quake also running at the same time).

The system hasn't crashed, and a check with e2fsck indicates that the ext4 partition is clean, however calculating the md5sum of the file created by the dd transfer reveals the data is not correct (though the file size is correct, so the data must just be gibberish).

I have rebooted this Raspbian system, and it has come up clean...

So it looks like my Pi doesn't like an over volt of +3 with just even a slight core overclock, which is strange as this hardware is quite stable at 1000/500/500/+6/(sdram ov)+4 - as long as I don't use the SD card as root. And it does seem to hang when the network is being hammered (maybe this is a separate and unrelated problem?)
Last edited by milhouse on Thu Sep 27, 2012 8:30 pm, edited 4 times in total.

zeeteex
Posts: 43
Joined: Sun Dec 25, 2011 10:59 am

Re: Overclocking

Thu Sep 27, 2012 8:23 pm

Hi guys, enjoying the new turbo mode and trying it out at 1100MHz with OV8... But would like to know if there is any way of maintaining that speed all the time rather than having it as an "ondemand" setting? Is this possible?

elatllat
Posts: 1337
Joined: Sat Dec 17, 2011 5:05 pm

Re: Overclocking

Thu Sep 27, 2012 8:24 pm

zeeteex wrote:Hi guys, enjoying the new turbo mode and trying it out at 1100MHz with OV8... But would like to know if there is any way of maintaining that speed all the time rather than having it as an "ondemand" setting? Is this possible?
I think that is what

Code: Select all

force_turbo=1
is for.
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FAQ : https://raspberrypi.stackexchange.com

Unanswered: https://www.raspberrypi.org/forums/search.php?search_id=unanswered

zeeteex
Posts: 43
Joined: Sun Dec 25, 2011 10:59 am

Re: Overclocking

Thu Sep 27, 2012 8:26 pm

So is the force_turbo=1 supposed to go into the config.txt file?
Raspi
arm_freq=1150
sdram_freq=600
gpu_freq=500
over_voltage=8

milhouse
Posts: 641
Joined: Mon Jan 16, 2012 12:59 pm

Re: Overclocking

Thu Sep 27, 2012 8:31 pm

zeeteex wrote:So is the force_turbo=1 supposed to go into the config.txt file?
Yes.

zeeteex
Posts: 43
Joined: Sun Dec 25, 2011 10:59 am

Re: Overclocking

Thu Sep 27, 2012 8:32 pm

Thanks! Learning all the time :D

dom
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Re: Overclocking

Thu Sep 27, 2012 8:33 pm

zeeteex wrote:So is the force_turbo=1 supposed to go into the config.txt file?
Yes, but if used with over_voltage, it will set your "warranty" bit.

zeeteex
Posts: 43
Joined: Sun Dec 25, 2011 10:59 am

Re: Overclocking

Thu Sep 27, 2012 8:35 pm

dom wrote:
zeeteex wrote:So is the force_turbo=1 supposed to go into the config.txt file?
Yes, but if used with over_voltage, it will set your "warranty" bit.
My warranty was gone long ago... Good thing i have two :) haha
Raspi
arm_freq=1150
sdram_freq=600
gpu_freq=500
over_voltage=8

milhouse
Posts: 641
Joined: Mon Jan 16, 2012 12:59 pm

Re: Overclocking

Thu Sep 27, 2012 8:46 pm

dom wrote:
zeeteex wrote:So is the force_turbo=1 supposed to go into the config.txt file?
Yes, but if used with over_voltage, it will set your "warranty" bit.
Is there any reason why we can't use over_voltage=8 when also using current_limit_override?

If I understand the wiki correctly, we can only use over_voltage > 6 with force_turbo=1, but I'd rather use dynamic rather than fixed clocks if possible, with the option of a voltage beyond 6.

dom
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Re: Overclocking

Thu Sep 27, 2012 8:51 pm

milhouse wrote:Is there any reason why we can't use over_voltage=8 when also using current_limit_override?
If I understand the wiki correctly, we can only use over_voltage > 6 with force_turbo=1, but I'd rather use dynamic rather than fixed clocks if possible, with the option of a voltage beyond 6.
The reason for tying it to force_turbo was to discourage its use (by triggering warranty bit).
I guess I could add something like force_turbo=2 which still allows dynamic overclock, but unlocks over_voltage=8 (and sets warranty bit).

milhouse
Posts: 641
Joined: Mon Jan 16, 2012 12:59 pm

Re: Overclocking

Thu Sep 27, 2012 8:54 pm

dom wrote:
milhouse wrote:Is there any reason why we can't use over_voltage=8 when also using current_limit_override?
If I understand the wiki correctly, we can only use over_voltage > 6 with force_turbo=1, but I'd rather use dynamic rather than fixed clocks if possible, with the option of a voltage beyond 6.
The reason for tying it to force_turbo was to discourage its use (by triggering warranty bit).
I guess I could add something like force_turbo=2 which still allows dynamic overclock, but unlocks over_voltage=8 (and sets warranty bit).
current_limit_override already sets the warranty_bit, so couldn't you unlock over_voltage=8 if current_limit_override is enabled?

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hojnikb
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Re: Overclocking

Thu Sep 27, 2012 8:56 pm

yeah overvoltage 8 with dynamic freq would be cool :D
+°´°+,¸¸,+°´°~ Everyone should have a taste of UK Raspberry Pie =D ~°´°+,¸¸,+°´°+
Rasberry Pi, SoC @ 1225Mhz :o, 256MB Ram @ 550Mhz, 16GB SD-Card, Raspbian

dom
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Re: Overclocking

Thu Sep 27, 2012 9:29 pm

milhouse wrote: current_limit_override already sets the warranty_bit, so couldn't you unlock over_voltage=8 if current_limit_override is enabled?
Sounds reasonable. It's on my list.

milhouse
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Re: Overclocking

Thu Sep 27, 2012 9:43 pm

dom wrote: Sounds reasonable. It's on my list.
Many thanks in advance! :)

Tompen
Posts: 20
Joined: Tue Aug 14, 2012 4:11 pm

Re: Overclocking

Thu Sep 27, 2012 9:48 pm

Made a quick test, only replaced start.elf with older versions. I tried these:
commit: a2747801 Added cpufreq driver. Added measure_temp vcgencmd.
commit: 59059dea Add low-latency mode to sdcard driver. Enable with sdhci-bcm2708.enab…

It made no difference for me. without core_freq=300 is OK, with core_freq=300 was corruption. But because I did both SD-card replacement and distro change since core_freq=513 without corruption, I think it is not wise to trust this quick test too much.

dom
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Location: Cambridge

Re: Overclocking

Thu Sep 27, 2012 9:56 pm

Tompen wrote:Made a quick test, only replaced start.elf with older versions. I tried these:
commit: a2747801 Added cpufreq driver. Added measure_temp vcgencmd.
commit: 59059dea Add low-latency mode to sdcard driver. Enable with sdhci-bcm2708.enab…

It made no difference for me. without core_freq=300 is OK, with core_freq=300 was corruption. But because I did both SD-card replacement and distro change since core_freq=513 without corruption, I think it is not wise to trust this quick test too much.
I'm interested if you can find an older start.elf that doesn't suffer corruption.

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