I am compiling LFS system, and i have compiled KDE 3.5.10 ( stable LFS suggest 3.5.9, but kde.org doesn't share it anymore). Everything went fine, but after i started kde the whole processor power was shared equally by kdesktop, kicker and kded. Additional kde-based programs like kate also eat as much processor as they can, when started. Strangely enough, konsole works quite well.

Except huge performance loss everything seems to work quite fine. There are no system log entries that i could relate to this problem.

I tried to ssh with X-tunneling from a different computer to check if it's not a fault of X-server. However, newly started kde was still eating CPU power. In reverse case (ssh connection from my computer to another one) everything was fine - i guess my X server has it's alibi then

Now i am thinking about either trying to compile kde 3.9 and see if problem remains, or recompiling kde 3.10 with debugging symbols and trying to figure out what it is doing all the time. As both compilations are quite time-consuming, i don't know which option is better.

What else I could do to find a source of this problem?

Not like I can help you with issue, but you need to post
make & model
cpu, mem

But I will tell you if you have limited resources, you will have even less when using remote.

Maybe your compile time parameters were wrong.

Why not try Gentoo which (I think) still supports KDE 3 but in forms of overlays.

make & model?

About my pc - it is Athlon 2000+ (1666MHz) + 1GB RAM - on my old ubuntu kde 3.5.10 works much quicker, and doesn't need almost any CPU power when doing nothing.

Yes but for how long will they support it? I want to keep using KDE3 at least for several years...

Gentoo is a source based distro. The maintainers don't have to maintain it, it maintains itself.

If the new GCC can't compile the old KDE you can install GCC 3.x which's still in the official Gentoo tree, and best of all, you can install multiple versions of GCC and even choose which one to use. I think Gentoo is the only distro to have this capability.

So is LFS - i compiled every piece of software i have
KDE compiled well, so i don't know if the problem is related to gcc. When i am out of options i will try older one.

But Gentoo has a package manager (rather the most powerful available in the industry) so you don't have to declare gcc flags every time you compile. Passing options is also made a piece of cake.

You should try it out you know, it'll be a lot easier than LFS but as powerful and customizable.

Here we go -

http://gpo.zugaina.org/kde-base/kde-desktop

I used only the ones from BLFS instructions

Perhaps it is a better idea - however i already have complete LFS system and i don't want to rebuild another one - and there is no guarantee that in newly built Gentoo the problem will reocurr. If i will rebuild my system again in the future, i guess i will give it a try.

For now i am looking for a solution to my kde-problem.

EDIT:

I found a rason. After reompiling and debugging i discovered that file alteration monitor library was spamming kde with alteration notifications. Strangely enough, I don't even remember instaling libfam... after removing libfam from lib/include dirs i recompiled again, and now it works perfectly.. Hope kde will be able to get file alterations only with INotify.