On Monday 04 April 2005 10:55, Jose Gonzalez Gomez wrote:
> Hi there,
> I've been experiencing performance problems in my laptop (Acer Aspire
> 1522WLMi). I have the feeling that the problem is related to hard
> drive performance, as whenever I do some I/O intensive task (mainly
> tested compiling Java code) my system performance goes down, and
> switching to any other application takes a lot (hard drive performance
> problem while doing swapping?). I hasn't been able to solve it,
> although I've read doco and tried tweaking the hd peformance with
> hdparm.

swap is incredibly slow on linux. As soon as you are hitting swap, your box is 
dead slow.

And this is not, because the swapping mechanism is stupid (it seems to be 
stupid for me, because it always swaps out the wrong things), but because how 
it reads the data back (if I remember right, there were some discussions on 
lkml in january and february about low swap performance).

For example:
I have 512mb ram, and this is enough. Really. But to be safe, I have 1gig 

So, I have KDE 3.4 with a lot of eye-candy running, some konqueror-windows 
with tabs, kmail, swap is not used.

I download BIGFILE (like some linux-isos), suddenly KDE is dead slow. Ok, the 
harddisk is doing a lot of stuff, so it is normal for everything that wants 
to load something is slow, but hey, the download has ended, BIGFILE lies 
around on my harddisk, but KDE is still mostly swapped out and the 
caches&buffers are huge(Reducing swappiness to 10 does not help)? What is 
that? And why does it not get better over the next minutes/hours?

How do I get my performance back? Easy: swapoff -a && swapon -a and bingo, KDE 
is lighting fast again.

Something is very broken in swapland, but at least the workaround is easy ...

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