Hi all,
I'm relatively new to xbmc, all though I've had it installed for a while I really haven't tinkered with it too much.
I have xbmc installed on a zotac ion-itx-b (single core) with 4gb ram, running Arch Linux. Everything is running very well and watching 720p movies is a breeze.
One thing I have noted though, and it bugs me somewhat, is that the cpu usage is always sitting at 20% (xbmc possesing all usage), even if I am at the home screen and the box has been idle for a very long time.
I have seen a few topics on people having problems with 100% cpu usage and such, but that is really not my problem.
My question is if 20% cpu usage is to be expected when the system is ideling? I would very much prefer it to be lower but before I go hunting for performance issues I thought I'd ask here first.
The reason I'm asking is that if I exit xbmc and let the box sit at practically 0% cpu usage the temperature drops from ~63C to 55C which is pretty important for me as the case I am using is quite small and badly ventilated.
So, what cpu usage is others having? Any chance of going lower from where I am at the moment?
# ps -eo pcpu,args | grep xbmc.bin | grep -v grep
10.6 /usr/share/xbmc/xbmc.bin -fs
cat /proc/cpuinfo | grep "model name"
model name : Genuine Intel® CPU 1300 @ 1.66GHz
model name : Genuine Intel® CPU 1300 @ 1.66GHz
~$ ps -eo pcpu,args | grep xbmc.bin | grep -v grep
28.0 /usr/share/xbmc/xbmc.bin --standalone
~$ cat /proc/cpuinfo | grep "model name"
model name : Intel® Atom™ CPU 330 @ 1.60GHz
model name : Intel® Atom™ CPU 330 @ 1.60GHz
model name : Intel® Atom™ CPU 330 @ 1.60GHz
model name : Intel® Atom™ CPU 330 @ 1.60GHz
A tad high imo.
31.9 /usr/share/xbmc/xbmc.bin --standalone
cat /proc/cpuinfo | grep "model name"
model name : Intel® Core™2 Duo CPU E8500 @ 3.16GHz
model name : Intel® Core™2 Duo CPU E8500 @ 3.16GHz
I think it's one of those things that they'll get around to addressing when they have time to. Several users have brought it up prior and their concern wasn't heat, but power consumption instead, as some users have to pay a higher rate depending on where they live.
There is a probably a trac ticket open for it somewhere. Search on
http://trac.xbmc.org
ION-ITX-A, 4GB. Hardy with Xserver 1.5.3, ALSA 1.0.21 and plenty of other offical & unofficial updates.
~$ ps -eo pcpu,args | grep xbmc.bin | grep -v grep
10.9 /usr/local/share/xbmc/xbmc.bin --standalone
cat /proc/cpuinfo | grep "model name"
model name : Intel® Atom™ CPU 330 @ 1.60GHz
model name : Intel® Atom™ CPU 330 @ 1.60GHz
model name : Intel® Atom™ CPU 330 @ 1.60GHz
model name : Intel® Atom™ CPU 330 @ 1.60GHz
r23388 @ 1360x768 PM.HD + Black Screensaver (enters energy saving after 30 mins)
This media player/server constantly sits in the main menu. No RSS, or Eventserver and UPnP stuff
antjoh Wrote:...
One thing I have noted though, and it bugs me somewhat, is that the cpu usage is always sitting at 20% (xbmc possesing all usage), even if I am at the home screen and the box has been idle for a very long time.
I have seen a few topics on people having problems with 100% cpu usage and such, but that is really not my problem.
My question is if 20% cpu usage is to be expected when the system is ideling? I would very much prefer it to be lower but before I go hunting for performance issues I thought I'd ask here first.
...
To explain, XBMC renders the screen at the vsync level, say 60 times a second. So even if the image look static it's still recalculated, redrawned 60 times a second. On a small CPU like atom it has to do alot of work feeding all that data to the GPU. Also XBMC uses quite much CPU when calculating how the skin is supposed to be presented, which it has to do for each frame.
This is a tradeoff for being skinnable, if we knew the skin the calculations could have been skipped, but still they aren't that costly it's not worth it.
So to reiterate, even if your system appears IDLE it may not be.
But that's enough of info about the problem, here is a quick fix. Select the black screensaver instead of the dim. Black screensaver will effectively hinder rerendering so CPU speed should be dramatically slowed down.
Cheers,
Tobias.
topfs2 Wrote:But that's enough of info about the problem, here is a quick fix. Select the black screensaver instead of the dim. Black screensaver will effectively hinder rerendering so CPU speed should be dramatically slowed down.
That screen svaver trick made quite an amazing difference. From 20% cpu usage down to ~4%. Very nice!
Thanks a lot for explaining the background to this too.