[lug] sluggish machine

Davide Del Vento davide.del.vento at gmail.com
Thu Jun 4 15:41:32 MDT 2009


I (involuntarily) trigger it again.

The fact:
CPU temperature was 81 degrees (Celsius)
CPU speed was 800MHz (and not speeding up while the system was sluggish)
/var/log/messages did not report anything
Xorg and firefox were the more than 90% CPU users (maybe I am hitting
the bug mentioned by Lee?)
NoScript was ON, but many (corporate, maybe heavy but hopefully not
rogue) websites were allowed
Probably a certain action on (corporate) MeetingMaker was trigging it,
but I was not able to reproduce it (when I try, the CPUs scale up to
1.2GHz, but the temperature now is about 75 degrees)

Any other suggestions?

Thanks,
;Dav

On Thu, May 21, 2009 at 16:48, Davide Del Vento
<davide.del.vento at gmail.com> wrote:
> Thanks everybody for the help.
> I'm replying to everything in just a consolidated email.
>
>> 1. RAM usage (is it swapping like mad?)
> No, or better, I know how it sounds and I'm not complaining when it is
> happening (after all if I need more than 2GB from a laptop I cannot
> complain... In these cases I should use the 128GB per node we have in
> bluefire, not the laptop...)
>
>> 2. I'd wonder about a failing hard drive
>> (anything in /var/log/messages that looks suspicious?)
> No, but I could be overlooking something. Any keyword to grep?
>
>> Next I'd grab a CD with memtest86 on it (CentOS install CD, for example
>> has it... you just type memtest86 at the CD boot prompt)
> Tried my ubuntu memtest86 availabe on the hard drive (this machine
> doesn't have any CD reader)
> I tried it a few times in the past, but never for so long. It took 14
> hours to arrive at the 6th test (of 10), with 48% of test successfully
> passed and no errors, so far. Notable data: 2038MB of memory, going at
> 1.8GB/s and ECC is off (I noted the whole page, but I'm not retyping
> it here, should I?)
>
>> Sounds more like a heat issue.  Check that the fan is running and that
>> the machine isn't hot to the touch.  Throttling the cpu is one way the
>> machine tries to protect itself.
>
> The fan sounds ok, but the heat sink might have been detached or
> something (it's a laptop, vibrations are always an issue....)
> After your advice, I installed the CPU-frequency-scaling and Sensors
> applet. I'm running 70-80 degrees (Celsius), since I installed the
> temperature monitor, but the laptop is colder than the maximum
> skin-feeling I remember.
>
> I did my homework to know what's the normal temperature for my U7600
> and I found what follows:
>
> http://download.intel.com/design/mobile/datashts/31674505.pdf (pag 79)
> indicates a 100 degree Celsium maximum operating temperature (of the
> chip, non of the case neither of the air). The shut-down temperature
> is 125 degrees (many other pages in the same PDF).
> Same numbers in this unofficial, but better readable table:
> http://www.cpu-world.com/CPUs/Core_2/Intel-Core 2 Duo Mobile U7600
> LE80537UE0092M.html
>
> So currently I'm running 20 degrees (40 F) lower than the maximum. The
> skin feeling I remember didn't was this hotter, but....
>
> ... so far I noticed that the CPU-frequency sometimes doesn't scale up
> quickly, and I get a little slower performance (nothing, compared to
> what I was telling in my previous email, but a clue): sometimes it
> sticks at 800MHz instead of scaling up to 1.2GHz.
>
>> One way to isolate the problem to the web is to just close firefox and
>> see if the problem goes away.
> I'd already tried this BEFORE you suggested, and this is what I found.
> I didn't have any chance to re-try it later (with the above-mentioned
> applets) because it didn't happen again.
> Anyway, when I closed firefox (very difficult, I had to kill it on a
> non-responsive system), the machine recovered, but not quickly enough.
> I mean, after you free ~200MB RAM and ~ 50% CPU usage, the system is
> clearly more responsive, but still slugglish. Only after lot of time
> it went back to "like new" (I didn't reboot just after because I had
> many ssh sessions open that I didn't want to lose).
>
>> You can also try to enable NoScript for firefox and see if that catches
>> which page is doing evil things, if any.
> This is a wonderful tool! I didn't know about it. Thanks for
> suggesting, I'll keep it always running now. I need to enable almost
> all of the websites I use, but I'm blocking everything I google and
> everything I don't explicitly need, great! I highly recommend it to
> everybody, even if currently you don't have any problem!
>
>> i'd bet you 100% it's your browser, especially if you tab browse a lot and
>> leave the browser running all day long.
> I often do. But as I wrote, it didn't seem to be the whole story. Indeed....
>
>> as someone else suggested, just kill the browser.  that'll be a quick test
>> if you're performance comes back.
> ... the performance didn't come back right after.
>
> So far, I think what was happening is the follows:
>
> a) the CPU was slightly overheat (possibly triggered by that heavy
> python script I mentioned)
> b) the CPU-frequency downscaled (maybe due to a? I have to do some
> homework on that and see how does it work)
> c) something in firefox was eating more than 50% CPU-time and lot of memory
> d) the rest of the apps eating the rest of the resources
> e) maybe I had also bad memory fragmentation, possibly caused by
> firefox and the python script
>
> c (and maybe also d) were aggravating a
>
> This would explain the observed behavior (including the slow "healing"
> after killing firefox, due to cooling down, that is surely much slower
> than freeing memory).
> I will try to trigger it again, leaving firefox on for a day with a
> lot of possible "evil" tabs and NoScript disabled. Then I'll run the
> heavy python script. If I will reproduce the heavy slow-down, the
> CPU-frequency and temperature applet will give me more info than just
> the system monitor applet saying 100% CPU-usage (this will happen at
> the beginning of June, until then I really will not have time to
> play...)
>
> Currently, I'm loving NoScript and I'm avoid the python script (even
> if I need it, but I need other things most), so this might explain why
> it's not happening.
>
> I will only need to figure out if there is a "trivial" hw problem such
> a wobble heat sink. I'll keep you posted!
>
> Thanks again everybody and let me know if you have any additional idea!
> ;Dav
>
> On Tue, 19 May 2009 16:09:56 -0600, "Davide Del Vento"
> <davide.del.vento at gmail.com> said:
>> Folks,
>> I'm having a weird problem. My laptop is slowing down often, up to a
>> point where it becomes unusable. Then it return faster as it was, or
>> sometimes (like when I wrote the first draft of this email) still very
>> slow, but usable - I am typing about two words forward the ones it is
>> showing on the screen.
>>
>> *********************
>> The facts:
>> The machine becomes incredibly slow, system monitor reports 100% CPU
>> usage, and many windows (most notably firefox) become irresponsive and
>> grayed-out.
>>
>> *********************
>> The clues:
>> System monitor (as well as top) does not report a single process that
>> is hogging all the resources, but it might not able to refresh often
>> enough. The top-six for memory and CPU are firefox, xorg, evolution,
>> thunderbird, system monitor itself and (oddly?) geyes. The rest are in
>> the single digit (or even 0.something) range.
>>
>> The obvious suspects are javascript in the large number of pages I
>> keep active in firefox (I need them, don't suggest to not use them,
>> they are almost all work related, besides gmail for chatting with
>> family and friends - maybe chrome would have been better to pinpoint
>> the guilty site, but we don't have it for linux)
>> On a similar system (older hw, same OS, maybe slightly different
>> packets installed - oddly less carefully picked, like skype) they the
>> same websites don't create this mess! So it's not (entirely) web's
>> fault.
>>
>> I did deleted my .mozilla directory and let firefox re-create it
>> again. Painful (autocompletion, history, settings lost, etc) and
>> useless: the problem si exactly the same. I unistalled  firebug (but
>> it was disabled...), I uninstalled completely firefox-3.0 and all
>> related packages (gnome-support, ubufox, etc), did apt-get autoclean
>> and autoremove. After reinstalling (firebug excluded) the problem is
>> still here (less frequent, maybe...)
>>
>> RootKit might be a possibility, but nmap didn't find anything, and
>> rkhunter, unhide and chkrootkit didn't find anything "too strange"
>> (well, it did find something, but many people online say that are
>> false positive - or are they the RootKit authors? - and then a true
>> positive might hide in the list). And I trust more nmap than
>> rkhunter, unhide and chkrootkit.
>>
>> Fragmentation may contribute to the issue, since everything started
>> when I had to create a couple of multi-gigabyte files (suddenly
>> raising my / usage from ~30% to ~70%) and I had to read these files
>> with my own python scripts to do some data-analysis. During that time
>> the system was REALLY sluggish and started to swap, but at the end the
>> process was successful. But fragmentation does not explain the 100%
>> CPU usage (which files should I check with filefrag -v?)
>>
>> *********************
>> The system:
>> Ubuntu Hardy 8.04.2 - fully kept updated
>> Linux-2.6.24-24-generic  i686
>> Gnome 2.22.3
>>
>> Dell Dual Core U7600 @ 1.2GHz
>> 2GiB RAM
>>
>> Usually used with Dell dock-station and external keyboard, mouse and
>> monitor.
>>
>> *********************
>>
>> Do you have any suggestion? Even if not, thanks for reading this long
>> message.
>>
>> Bye,
>> ;Dav
>



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