Re: Disk i/o overloading and cpu monitoring
El Lunes, 27 de Diciembre de 2004 16:37, Pol escribió:
> Hi all,
> I am running deb/unstable with kde 3.3.1 gui on my acer
> travelmate laptop (intel centrino cpu).
> In the last few days, my laptop has become almost unusable
> due to overloading input/output to the disk, that seems
> to be triggered both by desktop applications (e.g.kpackages,
> kaffeine, etc) and terminal applications entered through
> the konsole terminal emulation, e.g. apt-get, that freezes
> reading the database.
> As I have checked out, enough free swap area seems to be
> available, so no reason of such i/o is evident.
To fire disk i/o activity this is the perfect reason. You have swap area
available, and the kernel wants to use it. Look what effect has setting
/proc/sys/vm/swappiness. 0 -> almost no swap use, 100 -> everything to swap
quickly. Remember no swap means no disk cache in memory.
> Furthermore, from the system monitor on the kde panel
> displays one gets that almost 100% cpu is busy due to system
> activity, while 'top' is detecting a very low cpu
> activity - i cannot explain such inconsistent behaviour.
> Here are my questions:
> - What can be the origin of such high i/o traffic?
May be the loggin system? Sometimes famd goes crazy to the 100% and I have to
> - Why do the kde panel and 'top' report such different informations?
That is very strange. May be in top you do not calculate the total sum for all
> - How can i detect the program (system processes behind
> the running desktop application) that is actually performing i/o ?
Sure there is a better way, but, a
lsof -n | grep / | grep -v /proc | grep -v /lib/ | less
will tell you all open files. May be it gives you a clue.
I have read several times for laptops you should mount fs without atime,
disable kernel logging, and tune syslog via /etc/syslog.conf