KDE4 memory usage vs KDE3 => benchmark ?

[wazyk]

Hi,

Well yes, I'm a kind of KDE fanboy. Not for so long now, since 2005, using 3.5.x series.
I was very exited when KDE4 project came to life, to see this project beeing able to "rethink" itself for new and modern desktop experience.

Many articles were written at that period, describing the new aspects and technologies of KDE4.
Now KDE SC 4.4 is here, all these "pillars" have matured and proven that the whole project is on the right track.
There is one aspect that was discussed at that time that is not present anymore : KDE4 memory usage versus its predecessor. Maybe nobody cares...

I remember an article back in 2007 saying that KDE4 was using 40% less memory than KDE3. One would expect that, given what KDE4 promises, it would require better hardware to supprot it (I'll not talk about MS softs nor OSes here). And 40% is a lot, maybe too "marketing".

I just wonder now, if it is "really true". I feel that since KDE SC 4.4, it may be time to perform that benchmark, like we can have for Linux kernels. I have a familly life but not the time, hardware and skills to do that. But I would like to see that result, maybe some other KDE guys would be interested too.
Those 40% in themselves don't mean anything. It requires a methodological approach to compare memory footprints between two desktop environments.

I like Phoronix benchs and I hope it can be done, using several kinds of hardware, with or without visual effects, wih or without optional deamons (like Strigi indexation for instance), etc.

That is my request for you Phoronix guys, if you see some interest in that ...

[Melcar]

Well, from my usage experience KDE4 does have a smaller memory footprint. How much smaller I think it depends. When I was still on KDE3.x my memory usage at any given time would be in the 800MB-1.5GB range (more or less, can't remember the exact figures); that was with KDE3.x graphical effects and all that jazz. With KDE4.x and the same hardware I'm seeing smaller numbers, but I must say that they seem to change depending on the driver I use; with radeon I see 300MB-800MB, with fglrx I see 800MB-1.2GB, and with fglrx using direct2d 400MB-900MB (odd no?). All those numbers are from 64bit systems and desktop composition on.

[jmiahman]

In my experience as a Distribution Maintainer and Packager KDE 4 (the actualy kinit processes including kwin and plasma desktop) take up around 400M. When I last checked kde 3 (3.5) I was running it on a 512 Meg Machine at 200M. I would say KDE 4 takes up much more memory. It's a given rending SVGs and various animations that it's going to take up more. Maybe comparatively speaking ti takes up less, but in the real word that seems to be false.

[birdie]

OK, here are the real world results:

Memory usage before and after the start of:

KDE3:
             total       used       free     shared    buffers     cached
Mem:       3942172     383688    3558484          0       3928     101748
Mem:       3942172     576068    3366104          0      30376     199300

Total: 187MB

KDE4

             total       used       free     shared    buffers     cached
Mem:       3942172     386824    3555348          0       4660     10475
Mem:       3942172    1073012    2869160          0      24796     605136

Total: 670MB

Both environments were run with an empty, new profiles, and four applications which I just ran and kept open:

Akregator, Konsole, Konqueror and Kolorpaint.

Now, don't tell me KDE4 doesn't need a huge optimization.

[birdie]

KDE4 has almost reached Windows Vista/7 appetites which is a real shame taking into consideration a myth that Linux requires a less powerful equipment/PC to run.

Now, if you want to run KDE4 your rig must have at least 1GB of RAM and if you have just one GB of RAM, you'd better have at least 1GB SWAP enabled.

If you don't like thrashing your HDD, install at least 2GB of RAM to run KDE4 and your favourite applications, for instance, Firefox 3.6.4 can easily gobble up to 600GB of RAM even if you have Adblock+ installed and block most Flash animations.

[Kano]

You know that 64 bit needs much more ram than 32 bit too?

[birdie]

Both tests were carried out on the same 32bit PC (and the same distro).

[kraftman]

Now, don't tell me KDE4 doesn't need a huge optimization.

Which distro? For me it's about 250MB on 64bit Arch Linux and having some apps launched.

[kraftman]

@Birdie

And 32bit Windows XP consumes more memory on my system. Just be sure you're not measuring memory usage under Kubuntu, because there are some memory hungry things like python running.

[bugmenot2]

It would be more accurate to compare (free - cached) before and after startup. If you do this, you'll see that there's not much to choose between KDE4 and KDE3. http://www.linuxatemyram.com/ has some good reading on this.

If you want to dig in further on what is using the most memory, take a look at http://www.selenic.com/smem/ - this is one of the few apps that properly accounts for memory used by shared libraries.


It may still be interesting that cache size is much bigger in KDE4. Speculating wildly, that implies that KDE4 is loading much more from disk on startup (and would be taking longer to start). But you say that you're starting with empty profiles in both cases? Speculating even more wildly, I wonder if this is related to KDE4 building the pixmap cache on first run. It would be interesting to compare numbers on the second run.