How to know what causes a system to hang.

gabrielvc · 09-30-2009, 07:08 PM

Hi,

I am running Slackware 13, 01 00 00 00. I had to switch from kde to xfce, as the former gets really slow until it freezes. I have tried to use ps aux, when it is getting slow, to find out the reason, but the process seem to be doing fine. This is just when surfing the web, maybe looking some pdf files with okular, so there has to be something messing up the system.

Which tools (other than top, and ps) can I use to describe what is happening to my system? I can certainly install from sources anything that may be needed. Thanks.

(I do not want this to become a flame war about kde4, but I think the problema may be related to it. )

gankoji · 09-30-2009, 07:34 PM

Well, you have to do a few things before we can decide what's up. The most important thing you can install to your computer to solve this problema is, of course, you. You gave a general rundown of what you were using when the computer grinds to a halt, but what exactly have you been doing at the time this has happened the last few times. Does this occur every single time you use KDE? How long does it take for this problem to develop? What programs do you leave running either in the task bar or the sys tray?

Hopefully these questions will get you on the way to enjoying KDE again.
P.S. What hw are you using?

Bhagyesh · 09-30-2009, 07:39 PM

try

dmesg

or

/var/log/messages

this logs have some hardware related information.

hope that helps....

chrism01 · 09-30-2009, 07:40 PM

Well, the usual places I start are

top - (like you) shows both cpu and disk swap space
I'd have that open in an xterm continuously and keep an eye on it until the system freezes. It should give you a good idea of the cause.
You could try iostat, netstat, vmstat, but its a bit hit and miss unless you strongly suspect one of those areas.
There's even sar.
Try disabling all unneeded services eg apache etc. Basically, reduce the num of variables.

Try a df -h when the system slows down.

SharpyWarpy · 09-30-2009, 08:53 PM

Please tell us more about your hardware. How much RAM do you have installed? How fast is your CPU? How much swap space do you have allocated? If you don't know the latter run:
swapon -s
and:
df -h
and post the results. Also, the CPU might be getting too hot. If you have lmsensors installed run:
sensors
and post the results of that too, preferably when you start running slow -- if you can.
As mentioned in one reply, /var/log/messages can give some info SOMETIMES in this situation but don't count on it. Access this with:
less /var/log/messages | tail
Hope this helps.

gabrielvc · 09-30-2009, 09:16 PM

Hi, thanks for the reply.

This is a 2006 white MacBook, so it has:

1.83 Ghz Intel Core 2 Duo
1Gb DDR2 Ram
Intel GMA 950 integrated graphics/sound card.

The output of swapon -s is:
/dev/sda4 partition 1034496 159020-1

There is plenty of disk space, I had to replace the hard drive a couple of months ago:

Filesystem Size Used Avail Use% Mounted on
/dev/root 179G 46G 125G 27% /
/dev/sda2 50G 31G 20G 61% /osX
tmpfs 484M 0 484M 0% /dev/shm

The MacBook is aka "the oven", the white cover even decolorates due to this, right now is rather cool, though,

applesmc-isa-0300
Adapter: ISA adapter
Exhaust : 2401 RPM (min = 1800 RPM)
temp1: +35.5°C
temp2: +62.0°C
temp3: +57.0°C
temp4: +50.5°C
temp5: +53.2°C
temp6: +54.5°C
temp7: +57.2°C
temp8: +57.2°C
temp9: +57.0°C
temp10: +56.8°C

/var/log/messages starts having info only after the last reboot.

About the software running... there is no much to say. I though it may be okular, so I just open a few pdf's at a time (I used to keep dozens open when I had kde3.5). I also run firefox and emacs, but I don't think any of this applications to be the cause, since there is nothing bad when running them from xfce.

Thanks for the hints, I will post the logs near a crash soon.