Why all the cput is lost and where?

Dear all, there are times after my opensuse 12.1 is running for some period, like 5-6 days without rebooting, that the performance goes really down. It reminds me the old days of windows 98 where one had to reboot system quite a lot to keep performance up.

When this happes everything goes too slow (I have a four core cpu). Ksnapshot make 3-4 seconds to appear, writing text makes 2-3 seconds to appear in screen and so on…

What I tried intuitively is to understand if there is something eating up my cpu.
In the image below
Imageshack - cpulost.jpg
you will notice the problem

On the middle bottom ksysguard reports cput at 75%, which can be an indicator why the system is slowing down. Also the graphs show the four cpus being quite busy.

On the left side there is a ksysguard again showing the active processes ordered by cpu utilization, where you can see that the total sum of percentages does not get even close to the 75% .

Then I thought that there might be some root processes (I am the only one using that machine) eating the cpu so I sudo top. On the right side you will find the top running with root permissions.
Even there the cpu utilization reported does not get close to the 75%

What I am missing here and why I can not find what is eating cpu and makes system unresponive?

Could you please help me with that?

Regards
Alex

On Wed 05 Dec 2012 01:56:01 PM CST, alaios wrote:

Dear all, there are times after my opensuse 12.1 is running for some
period, like 5-6 days without rebooting, that the performance goes
really down. It reminds me the old days of windows 98 where one had to
reboot system quite a lot to keep performance up.

When this happes everything goes too slow (I have a four core cpu).
Ksnapshot make 3-4 seconds to appear, writing text makes 2-3 seconds to
appear in screen and so on…

What I tried intuitively is to understand if there is something eating
up my cpu.
In the image below
‘Imageshack - cpulost.jpg’ (ImageShack - Best place for all of your image hosting and image sharing needs)
you will notice the problem

On the middle bottom ksysguard reports cput at 75%, which can be an
indicator why the system is slowing down. Also the graphs show the four
cpus being quite busy.

On the left side there is a ksysguard again showing the active
processes ordered by cpu utilization, where you can see that the total
sum of percentages does not get even close to the 75% .

Then I thought that there might be some root processes (I am the only
one using that machine) eating the cpu so I sudo top. On the right side
you will find the top running with root permissions.
Even there the cpu utilization reported does not get close to the 75%

What I am missing here and why I can not find what is eating cpu and
makes system unresponive?

Could you please help me with that?

Regards
Alex

Hi
You have a lot of disk I/O in wait ~50% plus your using swap, with 8GB
of ram I would not expect that.

I would guess it’s you rsync job causing the I/O wait, run the iostat
command;


zypper install sysstat
iostat 2

Run it with and without the rsync running and see if that makes a
difference.

What device are you running rsync too (maybe a slow device)?


Cheers Malcolm °¿° (Linux Counter #276890)
openSUSE 12.2 (x86_64) Kernel 3.4.11-2.16-desktop
up 1 day 0:57, 3 users, load average: 0.21, 0.12, 0.07
CPU Intel i5 CPU M520@2.40GHz | Intel Arrandale GPU

On 12/05/2012 02:56 PM, alaios wrote:
> What I am missing here and why I can not find what is eating cpu and
> makes system unresponive?

i can’t tell from what you posted, because i can’t see what was going on
with (for example) rsync, Skype, your sound system and others maybe…

that is, a machine can bog down for causes other than just all CPU power
is in use…like: if something is going on that completely FILLS the
I/O (in and out) pipe going between two locations (via rsync) then that
pipe is clogged and nothing else can pass through until there is a
break in the flow (maybe from your internal hard drive to an external
USB or even to some machine on the other side of earth–which would also
fill the networking pipe)

so, if the access to the on board hard drive is BLOCKED (by rsync) when
you click (or keystroke) to do a Ksnapshot, then the system has to
stop (or slow down) the rsync in order to access the hard drive to
execute the ksnapshot executable…

or, if you are streaming music from some online source which fills or
almost fills the in/out bound network pipe and at the same time your
Skype is being used by the skype network to relay traffic (yes, it can
do that) then you might get slow response if you click to (say) change
youtube…

bottom line is: there are more things than just CPU usage that can
(will) cause slow desktop response…and, most machines just don’t have
enough in/out capability to do every thing (huge down/uploads, stream
music, do a video chat on skype, etc etc etc) at once

next time, turn something off and see if the system becomes more
‘responsive’…

ymmv, OH and have a look at atop, iotop, htop…

OH2! there is no need to run top as root…


dd http://tinyurl.com/DD-Caveat
http://tinyurl.com/DD-Software