Author Topic: CB2 overcloking  (Read 11517 times)

arturbac

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CB2 overcloking
« on: December 25, 2013, 05:50:12 am »
Hi just wanted to share info about succesfull oc to 1.4GHz, ( i lowered it to 1.34GHz for 100% stability under long cpu havy loads, but it works ok on 1.4)
I modified also kernel voltages list, maximum Hw allowed freq in kernel, and script.bin.
So cpufreqd uses range up to 1.4GHz instead of 1.08GHz.

I took radiator from old vanta gfx board and just put on cb2.


[    0.542364] [cpu_freq] INF:-------------------V-F Table-------------------
[    0.542384] [cpu_freq] INF:   voltage = 1800mv    frequency = 1392MHz
[    0.542400] [cpu_freq] INF:   voltage = 1720mv    frequency = 1344MHz
[    0.542413] [cpu_freq] INF:   voltage = 1650mv    frequency = 1296MHz
[    0.542426] [cpu_freq] INF:   voltage = 1600mv    frequency = 1248MHz
[    0.542439] [cpu_freq] INF:   voltage = 1525mv    frequency = 1200MHz
[    0.542452] [cpu_freq] INF:   voltage = 1525mv    frequency = 1152MHz
[    0.542465] [cpu_freq] INF:   voltage = 1450mv    frequency = 1008MHz
[    0.542478] [cpu_freq] INF:   voltage = 1425mv    frequency =  912MHz
[    0.542491] [cpu_freq] INF:   voltage = 1350mv    frequency =  864MHz
[    0.542504] [cpu_freq] INF:   voltage = 1250mv    frequency =  720MHz
[    0.542517] [cpu_freq] INF:   voltage = 1150mv    frequency =  528MHz
[    0.542530] [cpu_freq] INF:   voltage = 1100mv    frequency =  312MHz
[    0.542543] [cpu_freq] INF:   voltage = 1050mv    frequency =  144MHz
[    0.542556] [cpu_freq] INF:   voltage = 1000mv    frequency =    0MHz
[    0.542568] [cpu_freq] INF:-----------------------------------------------
[    0.542591] [cpu_freq] INF:sunxi_cpufreq_initcall, get cpu frequency from sysconfig, max freq: 1344MHz, min freq: 720MHz

For 1.34GHz
cat /proc/cpuinfo
Processor   : ARMv7 Processor rev 4 (v7l)
processor   : 0
BogoMIPS   : 2681.40

processor   : 1
BogoMIPS   : 2681.40

For 1.4GHz

cat /proc/cpuinfo
Processor   : ARMv7 Processor rev 4 (v7l)
processor   : 0
BogoMIPS   : 2777.16

processor   : 1
BogoMIPS   : 2777.16

Features   : swp half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpv4 idiva idivt

arturbac

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Re: CB2 overcloking
« Reply #1 on: December 25, 2013, 07:11:48 am »
diffs for kernel - change maximum freq and define volatages
Code: [Select]
diff --git a/arch/arm/mach-sun7i/cpu-freq/cpu-freq.c b/arch/arm/mach-sun7i/cpu-freq/cpu-freq.c
index aa36893..eb9463a 100755
--- a/arch/arm/mach-sun7i/cpu-freq/cpu-freq.c
+++ b/arch/arm/mach-sun7i/cpu-freq/cpu-freq.c
@@ -70,7 +70,15 @@ struct cpufreq_dvfs {
     unsigned int    volt;   /* voltage for the frequency    */
 };
 static struct cpufreq_dvfs dvfs_table[] = {
-    {.freq = 1008000000, .volt = 1450}, /* core vdd is 1.40v if cpu frequency is (912Mhz,  1008Mhz] */
+    {.freq = 1488000000, .volt = 1960}, /* core vdd is 1.96v if cpu frequency is (1440Mhz,  1488Mhz] */
+    {.freq = 1440000000, .volt = 1880}, /* core vdd is 1.88v if cpu frequency is (1392Mhz,  1440Mhz] */
+    {.freq = 1392000000, .volt = 1800}, /* core vdd is 1.80v if cpu frequency is (1344Mhz,  1392Mhz] */
+    {.freq = 1344000000, .volt = 1720}, /* core vdd is 1.72v if cpu frequency is (1296Mhz,  1344Mhz] */
+    {.freq = 1296000000, .volt = 1650}, /* core vdd is 1.65v if cpu frequency is (1248Mhz,  1296Mhz] */
+    {.freq = 1248000000, .volt = 1600}, /* core vdd is 1.60v if cpu frequency is (1200Mhz,  1248Mhz] */
+    {.freq = 1200000000, .volt = 1525}, /* core vdd is 1.53v if cpu frequency is (1152Mhz,  1200Mhz] */
+    {.freq = 1152000000, .volt = 1510}, /* core vdd is 1.51v if cpu frequency is (1008Mhz,  1152Mhz] */
+    {.freq = 1008000000, .volt = 1450}, /* core vdd is 1.45v if cpu frequency is (912Mhz,  1008Mhz] */
     {.freq = 912000000,  .volt = 1400}, /* core vdd is 1.40v if cpu frequency is (864Mhz,   912Mhz] */
     {.freq = 864000000,  .volt = 1300}, /* core vdd is 1.30v if cpu frequency is (720Mhz,   864Mhz] */
     {.freq = 720000000,  .volt = 1200}, /* core vdd is 1.20v if cpu frequency is (528Mhz,   720Mhz] */
diff --git a/arch/arm/mach-sun7i/cpu-freq/cpu-freq.h b/arch/arm/mach-sun7i/cpu-freq/cpu-freq.h
index 37a2457..cb27068e 100755
--- a/arch/arm/mach-sun7i/cpu-freq/cpu-freq.h
+++ b/arch/arm/mach-sun7i/cpu-freq/cpu-freq.h
@@ -37,7 +37,7 @@
 #define CPUFREQ_ERR(format,args...)   pr_err("[cpu_freq] ERR:"format,##args)
 
 
-#define SUNXI_CPUFREQ_MAX       (1008000000)    /* config the maximum frequency of sunxi core */
+#define SUNXI_CPUFREQ_MAX       (1344000000)    /* config the maximum frequency of sunxi core */
 #define SUNXI_CPUFREQ_MIN       (60000000)      /* config the minimum frequency of sunxi core */
 #define SUNXI_FREQTRANS_LATENCY (2000000)       /* config the transition latency, based on ns */

Offline kryoz

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Re: CB2 overcloking
« Reply #2 on: December 25, 2013, 07:23:24 am »
Great  8)
Does it really necessary to mount huge cooler for heat dissipation or the only radiator would be enough?
Did you heard also about fast ARM-chips degradation on significant overclocking?

arturbac

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Re: CB2 overcloking
« Reply #3 on: December 25, 2013, 12:39:12 pm »
- radiator would be enough up to 1344Mhz, but this samll coller powered 5V is quiet and allows more stable work.
- didin't heard about degradation of 'arm' cpus, but i read that A20 is designed to work up to 1,5GHz but CB/CB2 don't have any  radiators thus have heat problems and is stuck to work by default with 1,08GHz. So it isn't real OC, this is just what A20 could take when you mount anything that will take heat from core.
« Last Edit: December 25, 2013, 12:43:57 pm by arturbac »

Offline patwood

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Re: CB2 overcloking
« Reply #4 on: December 26, 2013, 05:44:42 pm »
- radiator would be enough up to 1344Mhz, but this samll coller powered 5V is quiet and allows more stable work.
- didin't heard about degradation of 'arm' cpus, but i read that A20 is designed to work up to 1,5GHz but CB/CB2 don't have any  radiators thus have heat problems and is stuck to work by default with 1,08GHz. So it isn't real OC, this is just what A20 could take when you mount anything that will take heat from core.

Where did you read that the A20 is designed to work up to 1.5GHz?  According to the datasheet, the max CPU voltage is 1.4v: https://github.com/OLIMEX/OLINUXINO/blob/master/HARDWARE/A20-PDFs/A20%20Datasheet%20v1.0%2020130227.pdf (see 5.1.  ABSOLUTE MAXIMUM RATINGS).  So 1.5GHz would seem to be pretty much impossible without going way outside spec.

arturbac

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Re: CB2 overcloking
« Reply #5 on: December 27, 2013, 08:48:19 am »
You are right about v for cpu from datasheet.
But Arm cpu is similar to x86 cpu it is just a chip. X86 also works by default in OC enviroment for years, just because there is colling system on it.
What is better pure A20 at 1008MHz or colder A20 at 1152 Mhz with radiator ?
:-)

Offline patwood

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Re: CB2 overcloking
« Reply #6 on: December 27, 2013, 10:43:20 am »
You are right about v for cpu from datasheet.
But Arm cpu is similar to x86 cpu it is just a chip. X86 also works by default in OC enviroment for years, just because there is colling system on it.
What is better pure A20 at 1008MHz or colder A20 at 1152 Mhz with radiator ?
:-)
Over clocking isn't just about heat dissipation.  Increasing the voltage can reduce the life of you CPU.  See
http://www.overclock.net/t/19390/info-why-does-too-much-heat-voltage-damage-the-cpu-scientific-version

arturbac

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Re: CB2 overcloking
« Reply #7 on: December 29, 2013, 12:05:44 pm »
Sure.
But who told that i need CB2 stable for 20yesrs ;-) , probably 1 or 2 years will be to long...
Take a look at ODroid U3/U2
http://hardkernel.com/main/products/prdt_info.php?g_code=G138745696275

They sell this at 1.7Ghz with radiator and CPU is designed to work with max 1.4GHz.
All is about heat, and of course shortning life of chip, but who needs chips for 10 years ...

Offline patwood

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Re: CB2 overcloking
« Reply #8 on: December 29, 2013, 04:05:11 pm »
If all you need is a year or two, you can probably run it as hot as you can without pushing the voltage so high as to make the junctions bleed current.

arturbac

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Re: CB2 overcloking
« Reply #9 on: December 30, 2013, 12:35:54 am »
Do you suggest lowering voltage ?

Offline patwood

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Re: CB2 overcloking
« Reply #10 on: December 31, 2013, 12:01:22 am »
Do you suggest lowering voltage ?

Depends on too many factors to be sure:

1. How good is Allwinner's silicon fab?
2. How good is AW's QA?  Do they pull out chips that can't run at 1.4GHz regardless of voltage? 1.3GHz? 1.2?  Who knows?
3. What is the expected MTTF for an A20 chip running at the spec's max voltage of 1.4v?  10 years?  20 years?
4. What is the max voltage that can be used on a *typical* A20 before the junctions leak so much current that they stop operating (not necessarily damaged, but at the point where some transistors are always "on" regardless of the current at the base, at which point they stop switching)?  Note that this will occur at approximately the same voltage regardless of clock rate (given good cooling).
5. How long will it take to cause an A20 running just below the voltage of #4 to degrade the silicon?

Obviously, 1 & 2 are only known to AW; 3 can only be determined over many years, although, again, AW (or their fab) probably has a good idea; 4 can be determined empirically, assuming that voltage level is in the range that can be set on the AXP209; 5 can only be determined by causing one or more chips to fail over some period of time that's probably too long to help in this discussion.

My advice: any time you go over manufacturer's specs, you take a chance.  Since we don't have a lot of experience with the AW designs or the chips from their fab (of fabs, if they use more than one), we can't extrapolate like we can with intel, amd, or nvidia (which had some manufacturing problems of their own a few years ago that caused chips to fail prematurely); that means overclocking AW chips is taking more of a chance than with intel or amd.


Offline Jojo

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Re: CB2 overcloking
« Reply #11 on: January 07, 2014, 02:49:06 pm »
Hi arturbac,

that looks interesting  ??? ! Just in case, that there are more people who are interested in overclocking and don't care so much about the lifetime reduction:
would it be possible that you write a more detailed tutorial about that what you did?
Is it also possible to set minimum and maximum frequency and voltage from user level ("performance governor")? So when you see that the CB is unstable one can clock it down at runtime?
That would be very helpful  8) ! Thanks in advance!

@patwood
Of course you are right. The A20 is a quite "new" CPU so there are not so many experiences about overclocking. But hey, why shouldn't it be some of us who check that out :) ? I am curious  ;) .

Greetings,
Jojo
Don't think that anyone will take more pains for his answer, as you took for your question.

Offline patwood

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Re: CB2 overcloking
« Reply #12 on: January 07, 2014, 04:43:48 pm »
@patwood
Of course you are right. The A20 is a quite "new" CPU so there are not so many experiences about overclocking. But hey, why shouldn't it be some of us who check that out :) ? I am curious  ;) .

Hey, better you than me!

I'm curious, too.  I did some overclocking tests with the A10 cause I had a bunch of different platforms (mk802, hackberry, cubieboard), but I didn't with the A20 cause I've only had this one cubieboard2 until recently.  Didn't want to "let the smoke out."

Offline Jojo

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Re: CB2 overcloking
« Reply #13 on: January 08, 2014, 02:26:36 am »
Hey, better you than me!
What do you mean?

I'm curious, too.  I did some overclocking tests with the A10 cause I had a bunch of different platforms (mk802, hackberry, cubieboard), but I didn't with the A20 cause I've only had this one cubieboard2 until recently.  Didn't want to "let the smoke out."

Yeah, the magic smoke... I know it ;) .
You are lucky. You have a CB2. I still have not received my CB2 at all! Since 4 weeks it is still "handed to customs". All in all I am waiting for five weeks now. That really p****s me off...

Greetings
Don't think that anyone will take more pains for his answer, as you took for your question.

Offline patwood

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Re: CB2 overcloking
« Reply #14 on: January 10, 2014, 10:41:05 am »
Hey, better you than me!
What do you mean?

I mean that I still only have 2 a20 boards now, so if someone else is willing to fry theirs in the interest of science, I'm very supportive of the effort  :D

Quote
I'm curious, too.  I did some overclocking tests with the A10 cause I had a bunch of different platforms (mk802, hackberry, cubieboard), but I didn't with the A20 cause I've only had this one cubieboard2 until recently.  Didn't want to "let the smoke out."

Yeah, the magic smoke... I know it ;) .
You are lucky. You have a CB2. I still have not received my CB2 at all! Since 4 weeks it is still "handed to customs". All in all I am waiting for five weeks now. That really p****s me off...

Greetings

That really sucks.  It's bad enough when delivery services like epacket take forever to get somewhere, but to be stuck in customs that long in the 21st century is crazy.