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Request for memtester results [Raspberry Pi 2]

Posted: Sat May 16, 2015 1:10 pm
by jaroslav.henzely
Hello
Since I read the thread about results of running memtester on Raspberry Pi 2,
viewtopic.php?f=63&t=103847
I decided to test mine too. I was shocked, when there was line telling:

Bit Flip : testing 168FAILURE: 0xffdfffff != 0xffffffff at offset 0x07027120.

I know, It is still $35 PC, but I am very strict when it comes to quality and stability.
Anyway, I ran it several times, and there was always at least one Bit Flip FAILURE.

So, can You please run memtester on Your Raspberry Pi 2 to investigate this phenomenon ?
Specifically the following command:

memtester 256M 1

and post here the output.
Thanks in advance.

The FAILURE occurs only when it comes to Bit Flip section, rest of the tests are O.K,
thus maybe it is only Firmware Issue with certain RAM operation.

Image

Image

Re: Request for memtester results [Raspberry Pi 2]

Posted: Sat May 16, 2015 2:43 pm
by vitor
I think mine went ok

Code: Select all

pi@raspberrypi ~ $ memtester 256M 1
memtester version 4.2.2 (32-bit)
Copyright (C) 2010 Charles Cazabon.
Licensed under the GNU General Public License version 2 (only).

pagesize is 4096
pagesizemask is 0xfffff000
want 256MB (268435456 bytes)
got  256MB (268435456 bytes), trying mlock ...locked.
Loop 1/1:
  Stuck Address       : ok
  Random Value        : ok
  Compare XOR         : ok
  Compare SUB         : ok
  Compare MUL         : ok
  Compare DIV         : ok
  Compare OR          : ok
  Compare AND         : ok
  Sequential Increment: ok
  Solid Bits          : ok
  Block Sequential    : ok
  Checkerboard        : ok
  Bit Spread          : ok
  Bit Flip            : ok
  Walking Ones        : ok
  Walking Zeroes      : ok
  8-bit Writes        : ok
  16-bit Writes       : ok

Done.
pi@raspberrypi ~ $ 

Re: Request for memtester results [Raspberry Pi 2]

Posted: Sat May 16, 2015 4:05 pm
by jaroslav.henzely
Damn, looks like RAM failure in my case :cry: Anyway,
enjoy Yours ;)

Re: Request for memtester results [Raspberry Pi 2]

Posted: Sat May 16, 2015 9:01 pm
by ktb

Code: Select all

ktb@jessie-rpi:~$ sudo memtester 256M 1
memtester version 4.3.0 (32-bit)
Copyright (C) 2001-2012 Charles Cazabon.
Licensed under the GNU General Public License version 2 (only).

pagesize is 4096
pagesizemask is 0xfffff000
want 256MB (268435456 bytes)
got  256MB (268435456 bytes), trying mlock ...locked.
Loop 1/1:
  Stuck Address       : ok         
  Random Value        : ok
  Compare XOR         : ok
  Compare SUB         : ok
  Compare MUL         : ok
  Compare DIV         : ok
  Compare OR          : ok
  Compare AND         : ok
  Sequential Increment: ok
  Solid Bits          : ok         
  Block Sequential    : ok         
  Checkerboard        : ok         
  Bit Spread          : ok         
  Bit Flip            : ok         
  Walking Ones        : ok         
  Walking Zeroes      : ok         
  8-bit Writes        : ok
  16-bit Writes       : ok

Done.

Code: Select all

arm_freq=1000
sdram_freq=483
core_freq=500
h264_freq=500
isp_freq=500
v3d_freq=500
over_voltage=4
over_voltage_sdram=2
avoid_pwm_pll=1
gpu_mem=256

Re: Request for memtester results [Raspberry Pi 2]

Posted: Sun May 17, 2015 1:17 pm
by jaroslav.henzely
After my little research (Googling) it looks like serious issue :oops:
A bit flip is when a binary value (a 0 or 1), is corrupted to have the opposite value (changing to a 1 or 0 respectively), which in turn corrupts the value of the number stored at the memory location suffering one or more bit flips.
http://betterembsw.blogspot.sk/2014/05/ ... ption.html

Image
http://1.bp.blogspot.com/-tz38lMri9-Y/T ... itflip.jpg

Re: Request for memtester results [Raspberry Pi 2]

Posted: Sun May 17, 2015 1:51 pm
by jojopi
jaroslav.henzely wrote:After my little research (Googling) it looks like serious issue :oops:
Yes. A computer is supposed to follow instructions precisely. Any "forgetfulness" in the accessible memory is a malfunction. Errors caused by things like cosmic rays should be so rare that you cannot readily detect them.

Can you reproduce the problem at the standard clock speed (no over-clocking), and with a power supply that is not producing under-voltage warnings?

If so, and unless you have previously voided the implied warranty by forced over-volting-over-clocking or other mistreatment, then you should contact the seller and ask for authorization to return the board for replacement on the grounds that there is a hardware fault that must have been present or latent since manufacture.

(One further question that would normally arise is how long you have had the device, but I do not think Pi2 have been on sale for long enough for it to be reasonable for them to fail due to age.)

Re: Request for memtester results [Raspberry Pi 2]

Posted: Sun May 17, 2015 7:41 pm
by jaroslav.henzely
O.K, I set sdram frequency to Elpida default, recommended by manufacturer in datasheet which is 400 MHz.
Default frequency of RAM in Raspberry Pi 2 is 450 Mhz

sdram_freq=400

And now, the memtester pass without FAILURE:

Code: Select all

root@PI:/# /home/pi/Downloads/memtester-4.3.0/memtester 512M 1
memtester version 4.3.0 (32-bit)
Copyright (C) 2001-2012 Charles Cazabon.
Licensed under the GNU General Public License version 2 (only).

pagesize is 4096
pagesizemask is 0xfffff000
want 512MB (536870912 bytes)
got  512MB (536870912 bytes), trying mlock ...locked.
Loop 1/1:
  Stuck Address       : ok         
  Random Value        : ok
  Compare XOR         : ok
  Compare SUB         : ok
  Compare MUL         : ok
  Compare DIV         : ok
  Compare OR          : ok
  Compare AND         : ok
  Sequential Increment: ok
  Solid Bits          : ok         
  Block Sequential    : ok         
  Checkerboard        : ok         
  Bit Spread          : ok         
  Bit Flip            : ok         
  Walking Ones        : ok         
  Walking Zeroes      : ok         
  8-bit Writes        : ok
  16-bit Writes       : ok

Done.
Sometimes it's better to follow the rules :mrgreen:
BTW: My power source can deliver up to 2 amperes at 5 volts (measured), plus it have large capacitors inside.

Re: Request for memtester results [Raspberry Pi 2]

Posted: Wed Sep 07, 2016 11:45 am
by e-raser
Hi,

I have serious issues with my Pi 2 for a few months, after it ran for about 140 days without any problem or a reboot. Services (e. g. SAMBA, PHP5-FPM, Webmin or - the worst, because having corrupted idb files is a lot of work to restore SQL backups - MySQL) stop working, but systemctl tells status "running" (green). The Pi also frequently restarts (I have watchdog enabled) every 1 to 3 days; logs not showing any possible reasons for this.

It even got worse, but I guess less related to memory issues: sometimes a few PHP and config files of productive web applications became modified (files contain rubbish characters, which of course can not be executed or read successfully), without (!) having the time stamp modified.

While this might be more a file system (and therefore a microSD) problem, the malfunctioning services looked to me like being a memory/RAM issue. I even disabled swap memory partition meanwhile.

Anyway, therefore I planned to switch hardware (I have another identical Pi 2, running as media center) to investigate if it really is a hardware fault.

Now I discovered this thread and I think it is worth a try (or two) to run memory check before testing a hardware swop.

Q1: What is the right parameter for checking the whole memory (like a "full test")?

Q2: I didn't get it, how adjusting some CPU/overclocking settings may change/resolve a potential memory issue. Can you please describe the connection more precisely please @jaroslav.henzely?

Q3: Did you make any bad experiences like I did and described above @jaroslav.henzely?