Bug#633815: jackd2: High CPU usage following sleep (top reports 190% on quad-core)

[Joel Roth]

On Thu, Jul 14, 2011 at 07:25:39PM +0200, Adrian Knoth wrote:
> On 07/14/11 01:49, Joel Roth wrote:
> 
> Hi!
> 
> > Package: jackd2
> > Version: 1.9.6~dfsg.1-2
> > Severity: normal
> > 
> > Observed when running jackd with user privileges.
> > 
> > System is extremely sluggish until I kill jackd.
> 
> Can we have some numbers, please?

> Many people run jackd2 with user privileges, that's actually the
> recommended way, and none of them experiences a substantial slowdown.
> 
> So we need to find out what's wrong with your system or particular
> setup.
> 
> I suggest a procedure like this:
> 
>    0. Update to the current package version
>    1. Stop jackd (killall -9 jackd, if need be)
>    2. Start top, htop or another CPU
>    3. Start jackd -d dummy
> 
> This must not trigger an considerable increase in CPU usage. Then, stop
> this jackd and start your real jackd. Which parameters do you use? Which
> soundcard is it?
 
00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series
Chipset High Definition Audio (rev 06)

A couple of naive attempts with version 1.9.7~dfsg-1
don't show any slowdown.

I'll look into this further. My parameters are mostly defaults:

jackd -d alsa -d hw:0,0 -r 44100 -H

Thanks for your attention.


> Increasing the buffer size will ease the timing and hence lower the CPU
> load. Assuming you use ALSA:
> 
>    $ jackd -d alsa -p 2048  --> relaxed timing
>    $ jackd -d alsa -p 128   --> stresses the CPU a bit more
> 
> In case of firewire audio interfaces, there has been made a fix recently
> that triggered tons of error messages to be printed on the console, thus
> making the entire system awfully slow. The newest package has the fix.
> 
> 
> Cheers

-- 
Joel Roth