Long compilation time and high temperatures

laci92 · n00b Joined: 28 Aug 2011 Posts: 32

I am aware that compiling large packages can take some time, but this is a bit odd. I have a Lenovo ThinkPad E520 (Intel Core i5-2410M dual-core 2.4GHz Sandy Bridge, 4GB RAM, Intel GMA HD 3000 and Radeon HD 6630M graphics), but compiling Firefox took 51 minutes (checked with qlop -tHg). Also, when updating the system, compiling GCC took 35 minutes, GHC took even longer when I was installing Layman. MAKEOPTS is set to -j8 and -march is set to native. Also, when compiling larger (or lots of packages), the XFCE sensor viewer shows that the temperatures for core0 and core1 are 90 and 87 degrees Celsius, respectively. When the system is idle or when I'm browsing, the sensor viewer shows that the temperature varies: 47 degrees for both cores, or 52 and 50 degrees for core0 and core1 respectively.
Is something misconfigured (or not configured at all) that causes longer compilation times? The processor temperatures are also worrying me because I don't know if it is normal, and I don't want to burn my laptop.

NeddySeagoon · Posted: Fri Oct 31, 2014 9:50 pm Post subject:

laci92,

At high silicon tempretures, the CPU will go into thermal throttling. This slows the clock to stop the tempreture going higher and slows compiles an a result.

Using -j8 may be counter productive too. You are probably well into CPU cache thrashing, which happens when one jobs CPU cache is evicted to make room for another job.
All the extra fetches from RAM slow things down.

To help cooling, support the edges of your laptop with a couple of thick books. This will allow heat to be removed from the bottom surface.
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Anon-E-moose · Posted: Fri Oct 31, 2014 11:16 pm Post subject:

The max you should be running is -j4 with that processor.
It's a 2 core, 4 thread cpu
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keet · Guru Joined: 09 Sep 2008 Posts: 568

You might want to get a laptop cooling pad with fans, or, if you are a bit brave, apply some proper thermal paste to your C.P.U.'s heatsink.

Also: https://dev.gentoo.org/~zmedico/portage/doc/man/make.conf.5.html

i92guboj · Posted: Sat Nov 01, 2014 8:52 am Post subject:

You should really use no more than -j3. -j4 at most.

If you intend to use your laptop while compiling stuff then I recommend -j2, but you can decide that based on your own experience.

What's sure is that -j8 is only crapping the whole thing out. Your cpu has 2 cores so having four threads for each core will have quite a few side effects, the worst of them being continuous context swapping, complete uselessness of in-cpu caches and (probably the worst) the fact that your RAM will fill completely causing disk paging which will -to all purposes- convert your i5 in a pentium4 with ultra DMA bus mastering disabled while emerge is running. I think that describes it pretty well.

That temperatures are something to worry about, indeed. But you should check if you get the same lectures with other distros, and if you can indeed feel such temperature by touching the bottom of the laptop. Maybe it's just that the lecture is wrong.

Other than that, if it's a new laptop and you can confirm that the lectures are ok you should as for a substitution or a refund. By opening it you will void the warranty.

keet · Guru Joined: 09 Sep 2008 Posts: 568

I had a long reply, but I was trying to press ctrl+f to see whether you had mentioned your fan, but it's next to w, so so much for that....

Do you hear the fan blowing when it is hot? You should. I have had two Lenovo laptops. One of them was 17" with an i5 (or maybe an i7), and it was silent (and cool) most of the time. When I was updating, though, as soon as the temperature went over 50, the fan turned on. It was quiet, but I could at least hear it. The temperature probably never exceeded 55 or 60.

My Lenovo L440, idles at about 35, and has probably never gone above 67. Something might be wrong with your fan.

Roman_Gruber · Posted: Sat Nov 01, 2014 1:49 pm Post subject:

Any of those notebooks i did maintenance had problems with the thermal paste.
A good thermal paste costs a few bucks but can save you a few degrees.
Dust in the system can also rise temperatures.
AFAIK every 6 months a notebook should be cleaned, sorry I can not quote the ressources

Some noteooks have poorly thermal design. therefore reading pages as notebookcheck or something else before buying hardware can prevent issues.

and temperatures around 90 degrees are no problems for cpus. the problem arises when the cpu starts to throttle because of poor thermal design or too safe settings in the bios from the manufacturer.

i92guboj · Posted: Sat Nov 01, 2014 2:19 pm Post subject:

90 is way too much and can't by any means be considered normal for any laptop cpu that I know of.

In any case, while admittedly it's not enough to burn most, it's definitely enough to harm nearby stuff in a laptop. Much more taking into account that most laptops haven't enough room for air to circulate.

laci92 · n00b Joined: 28 Aug 2011 Posts: 32

Thanks everyone for your reply. Sorry for my slow feedback, I was away a bit.

I will change MAKEOPTS to -j3, and I'll see how the laptop is behaving.