Latest MOC very resource hungry compared to older versions?

Submitted by SB on Mon, 2020-03-30 15:25

Forums:

MOC version: 
Comparison between 2.5.0 and newest version

Hellos,

I am using a quite old laptop for ncurses DJing and recently updated it to Lubuntu 18.04 i386 from Lubuntu 14.04. When the full setup is running, I have some terminals, mc, Qjackctl, Jack Rack and two instances of MOC open.

This was no problem at all on Lubuntu 14.04, but after the fresh install, one instance of MOC takes up to 25% CPU, according to htop. I tried all sorts of different settings for resampling, different settings in Qjackctl, with absolutely no difference. Audacious for example needs only ~1.5% when playing the same track.

I installed an old version of MOC (moc_2.5.0) and everything was running fine, as before the update. MOC needs less than 5%.

Is there any way, to get the newest version to run less resource hungry, like the old one?

Thanks for your help
SB

SB

Mon, 2020-03-30 17:25

PS The old version I tried and that is working well is called
moc_2.5.0~beta1+svn20131120-1_i386.deb

With "newest version" I mean the one in the official Lubuntu repos.

jcf

Mon, 2020-03-30 20:26

This was no problem at all on Lubuntu 14.04, but after the fresh install, one instance of MOC takes up to 25% CPU, according to htop.

So the obvious question is: what is the difference between the instance which takes 25% and the instance which doesn't? (You might want to clarify "instance". Do you mean one sever and one client, one server and two clients or two clients each with its own server?)

With "newest version" I mean the one in the official Lubuntu repos.

And which MOC version would that be?

SB

Mon, 2020-03-30 22:52

I am using two clients with their own server, to simulate two different "decks" with their own ouputs on my soundcard.
But this also happens, when running only one.

The new version that comes from the official repos of Lubuntu 18.04 has the number 2.6.0 r2949.
mocp -V says 2.6-alpha3.
I just tried the version of Lubuntu 16.04, with the number 2.6.0 r2788 - (2.6-alpha1) it behaves like the old one I used before, with less CPU usage.

About the difference: I really don't know. This happens with the exact same configuration.

jcf

Tue, 2020-03-31 09:09

So if I'm interpreting this correctly, the change occurred between MOC 2.6-alpha1 (r2788) and 2.6-alpha3 (r2949), and the audio path between the two instances (one low CPU, the other much higher) of 2.6-alpha3 diverge at the point of the output being used on the soundcard.

How do the two sound card outputs differ in terms of supported audio characteristics (e.g., sample rates, bit depths, etc) and any additional audio processing (e.g., sound subsystem plugins)?

SB

Thu, 2020-04-02 11:43

So if I'm interpreting this correctly, the change occurred between MOC 2.6-alpha1 (r2788) and 2.6-alpha3 (r2949)

Correct.

and the audio path between the two instances (one low CPU, the other much higher) of 2.6-alpha3 diverge at the point of the output being used on the soundcard

No. It doesn't matter, which sound card or how many outputs I am using, if I am running additional plugins in the Jack chain or not, or how many instances are running. Alpha3 always takes much more CPU. Also, if it is simply connected to Jack, with nothing else.

SB

Thu, 2020-04-02 11:44

Forgot to mention, that CPU usage is normal when idle. It only jumps up, when MOC is playing.

jcf

Thu, 2020-04-02 20:20

When you said earlier

... and two instances of MOC open

and

... one instance of MOC takes up to 25% CPU

you weren't meaning that only one of those two instances takes 25% CPU and the other doesn't, but rather that any running instance of MOC chews up the CPU?

SB

Thu, 2020-04-02 21:00

Correct, two instances of MOC together use over 50% of the CPU.