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[Q] Nexus 5 SoC/CPU temperature

OP plingpling

6th January 2014, 11:12 AM   |  #1  
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Hi all.

I am interested in locating the current SOC/CPU temperature on an Android Nexus 5 under operation. It is easy to retrieve the CPU frequency for each core by reading of the values from /sys/devices/system/cpu/cpu1/cpufreq/scaling_cur_freq while the phone is connected to a client - but the SoC temperature is usually found in different locations - based on the device / SoC vendor.

The device under test - holds a Snapdragon 800 / Hammerhead, revision 2.2, Plattform version 65536 - running Android 4.4.2

Our interest is to correctly identify when the device starts to throttle the frequency - and to report the accurate temperature at that moment. The work is used within the context of academic research. My role as a student is to identify how high temeperatures can affect throughput in computing intensive environments - and thus, more accurately provide reproducable results.

I am not interested in locating an app for this. I am interested in locating the thermal endpoint that reports the operating temperatue of the SoC. I am going to write the app myself - and dont need the overhead and interference of background services.
We have previously done this with the Samsung Galaxy Nexus, running on a Texas Instruments based SoC (OMAP) - but as noted, different vendors, different locations.

I tried to ask for this information on the Qualcomm developer forums, but their boards function quirky.

In advance. Thank you.
6th January 2014, 02:21 PM   |  #2  
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I can tell you that the frequency throttle is 60c based upon the stock kernel.

the suspend temperature is 60c

the core throttle is 80c

core throttle suspend temperature is stock 80c

the temp in which the device will throttle untiul reduced is 5c, the core throttle temp hysteresis is 10.
6th January 2014, 06:08 PM   |  #3  
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Quote:
Originally Posted by mistahseller

I can tell you that the frequency throttle is 60c based upon the stock kernel.

the suspend temperature is 60c

the core throttle is 80c

core throttle suspend temperature is stock 80c

the temp in which the device will throttle untiul reduced is 5c, the core throttle temp hysteresis is 10.

Hi! My CPU temperature is about 80-82C when gaming and about 65C when browsing chrome, facebook and some otther apps. What do you think, is that okay?
Hammer_Of_The_Gods
6th January 2014, 06:11 PM   |  #4  
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Hi,

Some reading, maybe...: http://forum.xda-developers.com/show...&highlight=hot and http://forum.xda-developers.com/show...&highlight=hot (and there is others).

6th January 2014, 06:13 PM   |  #5  
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Quote:
Originally Posted by Algotis

Hi! My CPU temperature is about 80-82C when gaming and about 65C when browsing chrome, facebook and some otther apps. What do you think, is that okay?

ha, you are persistent. its normal!

---------- Post added at 01:13 PM ---------- Previous post was at 01:12 PM ----------

Quote:
Originally Posted by viking37

Hi,

Some reading, maybe... http://forum.xda-developers.com/show...&highlight=hot (and there is others).

lol, thats his thread!
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Hammer_Of_The_Gods
6th January 2014, 06:17 PM   |  #6  
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Quote:
Originally Posted by simms22


lol, thats his thread!

Hi,

Bah, he will re read it in this case with all the explanation given, just a head up... He will finally understand some things about "pseudo" overheating?

I also replied in some of these threads here with the same thing, like you, these thread topics/questions/posts about "Nexus 5 hot, overheating, too hot etc..." like in the Nexus 4 section bother me, but it's just my opinion...

If not, I'm sorry to use the search function (quickly right)...

In any case it's not the goal of the OP to know "Why is my N5 overheating when I'm playing for 15 mins an heavy game" or something like that, I was replying to Algotis...

Last edited by Hammer_Of_The_Gods; 6th January 2014 at 06:39 PM.
6th January 2014, 07:06 PM   |  #7  
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Quote:
Originally Posted by mistahseller

I can tell you that the frequency throttle is 60c based upon the stock kernel.

the suspend temperature is 60c

the core throttle is 80c

core throttle suspend temperature is stock 80c

the temp in which the device will throttle untiul reduced is 5c, the core throttle temp hysteresis is 10.

Quote:
Originally Posted by simms22

ha, you are persistent. its normal!

---------- Post added at 01:13 PM ---------- Previous post was at 01:12 PM ----------



lol, thats his thread!

I believe you, i just cant understand why do ppl say that their phone is not that hot, max 65C...
6th January 2014, 07:19 PM   |  #8  
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Quote:
Originally Posted by Algotis

I believe you, i just cant understand why do ppl say that their phone is not that hot, max 65C...

people tend to embellish, make things sound better than they actually are. if you see who is saying that their phones hot or not, youll notice people that are new to xda, or dont post much, that say their phone doesnt heat up. yet, you see more people who have been on xda a while, or post more often, post that the phone can get hot. personally, i believe in being truthful and honest, even if the truth isnt good.
7th January 2014, 10:49 AM   |  #9  
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We attempted to measure the temperature from the following thermal sensor location:
/sys/class/thermal/thermal_zone7/temp

The idea came from a forum post about CPU temperature measurement on Nexus 4 devices - where the vendor was Qualcomm as well.
I cannot confirm that this is the correct measurement point, but it does raise and fall based on workload - and the values make sense as they represents temperatures from 30-75 C.

Looking at the following measurements, leave little doubt that the temperature throttels. The frequency drops down to 1.2-1.5 GHZ after a few minutes.



Does anyone have better ideas?

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