[SOLVED] My system is has become nexpectedly slow !

lalebarde · Last edited by lalebarde on Fri Jun 15, 2012 8:27 am; edited 1 time in total

Hi all,

Since the system & world update I performed one month ago, my system is very slow. For example, it can take 30 sec to change from one desk to another, to open an application menu, to flush the text I type in the console. I performed yesterday another update, but it is still the same. I have tried to investigate, but I found nothing.

Some times it is reactive, but only for a few seconds.

Any advice please ?

Here are some information :

Hypnos · Posted: Wed Jun 13, 2012 9:08 am Post subject:

Top seems to indicate nothing is hogging the CPU, though you might it easier to see using htop.

You'll also want to install iotop to see if any disk I/O processes are dominating.

Does this phenomenon happen in your desktop session, or also on the text consoles? Try not starting X and see how the text consoles behave.

What if you turn off swap? (On a related note: why in the world do you have 16GB of swap? If you 8GB RAM, and you don't hibernate, you shouldn't need swap at all.)
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lalebarde · Posted: Wed Jun 13, 2012 11:10 am Post subject:

Thanks for your help Hypnos,

Here is the result of iotop in cumulative mode during around 20 seconds :

Hypnos · Posted: Wed Jun 13, 2012 1:27 pm Post subject:

Your I/O usage seems insignificant.

Does your /var/log/Xorg.0.log say anything interesting? These would be lines with "(EE)" or "(WW)".

Also, your VIDEO_CARDS variable in make.conf confuses me -- why do you have both "nvidia" and "nv" ? What are the Video4Linux drivers for? Anyway, you can try clearing all of these and having just "nouveau" for the open source drivers.
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djdunn · Posted: Wed Jun 13, 2012 1:28 pm Post subject:

which DE do you use with X? Possibly you have a hard drive failing? I have noticed some severe I/O choking where it tries to read but cant, right before SMART decides it wants to fail, if i remember right it felt like 100% cpu usage and low memory conditions, choking I/O, like as if i was compiling, when in fact KDE and most of my services was idle. you could run a few hdparm -tT tests on each of the drives to see if the throughput of one is far below the others.

nvidia drivers should be completly fine, i like nouveau but am waiting for it to mature more, and its ok to have nv compiled too as a backup incase something goes wrong with your nvidia so you dont have to compile the nv drivers.
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lalebarde · Posted: Wed Jun 13, 2012 10:17 pm Post subject:

After a lot of investigations, it seems that it is the opera browser that makes this mess. When I stop it, everything becomes normal !!! I even tried a stress test with many heavy applications launched. Reactivity is alright. I will check the stability until tomorrow night.

Anyway, here are the answers to your questions :

Hypnos · Posted: Thu Jun 14, 2012 4:24 am Post subject:

It's odd that that Opera is causing the slowdown without hogging the CPU (as would be indicated by [h]top). Have to wonder what the interaction is that is causing the slowdown.

Since Opera is closed source, your best bet to diagnose the problem might be to run it with "strace", see if there are any frequent system calls that can give a hint about the issue.
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lalebarde · Posted: Thu Jun 14, 2012 10:04 am Post subject:

Here is the result of strace, attached to opera when it the system becomes slow.

With no swap :

Hypnos · Posted: Thu Jun 14, 2012 11:56 am Post subject:

How long did you run strace to produce that output?
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lalebarde · Posted: Thu Jun 14, 2012 12:14 pm Post subject:

I have not measured. But if I take the min and the max of the time stamped in the file, I have : 20955−20209 = 746" = 12'

The file size is 11.6Mb.

The command I used are, after having started opera and wait for slow-down :

Hypnos · Posted: Thu Jun 14, 2012 12:50 pm Post subject:

Here's my 12-minute strace of firefox under normal usage (web browsing, kernel build):

lalebarde · Posted: Fri Jun 15, 2012 8:26 am Post subject:

I have unmasked opera and upgraded from 11.64.1403 to 12.00.1450
Everything works fine now.
Thanks a lot.

Hypnos · Posted: Fri Jun 15, 2012 8:31 am Post subject:

Great! It sucks when you web browser is the problem -- tough to live without.
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