Re: [gentoo-user] KDE ridiculous memory usage

[Alex Schuster <wonko@wonkology.org>]

Florian Philipp writes:

> I have a bit of a problem. I'm on KDE-4.4.5 and it eats memory for
> breakfast. Directly after booting, everything is okay but the usage
> grows significantly. I wonder whether this is expected behavior.

I was just about to write something about this. I suffered from bad
performance for quite a while now (like mplayer stuttering during
emerges), started a thread in in the gentoo-performance list and got some
advice that made things a little better, but I suspect the effect came
from reduced memory usage only. Since yesterday the problems all seem to
be gone, but again it's not a real solution, as I plugged in another 2GB
of memory, so now I have 6G.

I used to restart kdm once per day in order to free memory. If I did not
do this, KDE4 became nearly unsusabe.

> The following statistics have been taken after 8 days of uptime during
> which the system was on standby most of the time during work days and
> at night.
> 
> free -m
>              total  used  free  shared  buffers  cached
> Mem:          3754  3588   165       0       57     258
> -/+ buffers/cache:  3271   482
> Swap:         6142   978  5163
> 
> A desktop machine that has 4GB RAM and still needs to swap?!

After 1 day of uptime, my system needs even more, but I'm also running
some stuff.

wonko@weird ~ $ free -m
             total       used       free     shared    buffers     cached
Mem:          5721       5618        103          0        112       1108
-/+ buffers/cache:       4397       1323
Swap:         4094         50       4044


> Excerpt from top:
>  VIRT  RES  SHR S %CPU %MEM     TIME+ COMMAND
> 1094m 484m  10m S    0 12.9  96:43.01 firefox
>  932m 471m  15m S    0 12.6   5:10.20 akregator
>  384m 303m 2856 S    0  8.1  59:43.43 virtuoso-t
>  709m 282m 2936 S    0  7.5   0:40.51 nepomukservices
>  839m 146m  15m S    0  3.9   8:37.76 thunderbird-bin
>  191m 131m  532 S    0  3.5  12:30.73 dbus-daemon
>  902m 105m 5288 S    0  2.8   0:30.16 krunner
>  263m 105m 1724 S    0  2.8   2:31.18 squid
>  255m  61m 6672 S    7  1.6 305:04.24 X
> 1106m  55m 7756 S    0  1.5   4:22.73 amarok
>  534m  54m  10m S    0  1.5   2:33.94 kopete
>  559m  52m 6536 S    0  1.4  56:52.37 nepomukservices
>  718m  38m  12m S    4  1.0 143:36.62 plasma-desktop
>  295m  33m 2048 S    0  0.9   1:59.32 mysqld
>  360m  17m 1856 S    0  0.5   0:07.56 tomboy
>  445m  16m 3392 S    0  0.4  38:54.36 nepomukservices
>  365m  14m 6356 S    1  0.4  27:38.49 konsole
>  438m  11m 4928 S    0  0.3   0:20.12 kded4
>  508m  11m 6364 S    0  0.3   0:45.79 kwin

Now this looks different here. I have X with 946M, plasma-desktop with 
505M, that's 15 times the memory you need. Then comes java with 371M (for 
TV-Browser - yes, 371MB just for showing the TV programme!), emerge wants 
272M while emerging openoffice. Chromium also needs much memory, my 33 
tabs want 762M:

 VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND			
1722m 946m  22m R	24 16.5 217:29.77 X 				
1728m 504m  23m S	 0  8.8  61:07.82 plasma-desktop	
2018m 371m 6772 S	 0  6.5   2:45.60 java  			
 379m 272m 1884 S	 0  4.8   4:39.50 emerge			
2632m 127m  11m S	 0  2.2   6:48.31 pica  			
 694m 123m  21m S	 0  2.2  11:28.50 kontact			
1246m 117m  20m S	 0  2.1  27:30.34 amarok			
 757m 101m  86m S	 0  1.8 116:20.68 vmware-vmx		
 946m  94m  10m S	 0  1.7   1:37.32 chrome			
 682m  91m  15m S	 0  1.6   4:22.98 chrome			
 494m  79m  14m S	 0  1.4   0:40.28 kmymoney  		
 929m  61m  13m S	 0  1.1   2:29.96 chrome			
 328m  56m 5084 S	 0  1.0   1:46.09 kio_imap4 		
73712  49m  616 S	 0  0.9   0:10.79 screen	
 921m  48m  30m S	 0  0.8   0:01.62 systemsettings	
 573m  46m  14m S	 0  0.8   1:36.06 dolphin

> Okay, I'm used to Firefox taking much memory. I'm okay with that since
> it's the most heavily used application currently running. But why does
> Akregator need that much memory? It doesn't even have any tabs open at
> the moment and is just running minimized in the background.

Beats me.

> Virtuoso looks like an optional Soprano dependency which in turn is
> needed for Nepomuk. Are the default use flags for dev-libs/soprano
> suboptimal? What happens if I choose other flags for Soprano?

Don't know. But you can just turn off virtuoso in systemsettings-> desktop 
search.
I just turned it on again, and - now I need 271M of swap, and again my 
system becomes unresponsive due to the constant swapping that is going on. 
With 6G!

Which is another problem I think. One question is how KDE4 can need such a 
lot of memory, the other is how the system can become so unresponsive once 
its starts swapping. I used to have larger swap with less RAM, and did not 
have those performance problems. One year ago I usually had 2G tmpfs for 
/var/tmp/portage, nowadays (with 4G) I cannot emerge things while working 
with the system (like, watching videos with mplayer). It feels like as 
soon as RAM is not enough and swapping occurs, the system swaps stuff that 
it will need again immediately.

What stuff do I run? I have 8 activities/desktops, there are some 
screenshots at [1] in case someone is interested. My default session has 4 
konsoles with a total of 8 tabs, 3 dolphins with 5 views, amarok, kontact, 
kmymoney2. TV-Browser (java application which eats a lot of memory), some 
admin tools like gkrellm or diagnostic plasmoids. And a lot of browser 
tabs, around 30. Currently I'm using chromium, that seems to use less 
memory than konqueror. The number of tabs increases with uptime. Is this 
too much? Desktop effects are enabled. Today I started openoffice once, 
played a little quake3. There is a windows VM running with vmplayer, but 
that takes only 50MB. wine uses more, I'm using this today, but normally 
not.

The system is an AMD Athlon 4850e (2 cores, 2500MHz) with 4GB of RAM. 
Everything is on LVM, most partitions are LUKS-encrypted. /var/tmp/portage 
is unencrypted, and at the moment swap is also not encrypted and on my 2nd 
drive. The encryption does not be much of an overhead, when the system 
stutters, top shows a large wa(it) value, and not much CPU usage. swappiness
is set to 10.

Any ideas? I might just get another 2G, and then the problems will be gone,
but I think this would be only a workaround. 6G should be enough already
even when using lots of applications, shouldn't it`?

BTW, I emerged and tried KDE 3.5 a week ago. Cool, things were fast
there. Probably because it needs less memory. But I don't want to go back.

	Wonko

[1] http://archives.gentoo.org/gentoo-performance/msg_e4365aee884ee527dc8fb82d2c725ec4.xml