[squeak-dev] Sound mixing makes nasty noises

Herbert herbertkoenig at gmx.net
Fri Dec 25 14:45:24 UTC 2020

I just downloaded Squeak on my up to date Linux Mint computer (a Core I
3 from 2009) and right at the start (before the message you report) I
get the message copied below.

No sound with vm-sound-alsa but sound with vm-sound-pulse and always the
same message. But it sounds like high latency and not as bad as on the
Pi (with the keyboard). When waggling the keyboard Squeak goes from 5%
to 56% CPU. That seems a lot to me.



pthread_setschedparam failed: Operation not permitted
This VM uses a separate heartbeat thread to update its internal clock
and handle events.  For best operation, this thread should run at a
higher priority, however the VM was unable to change the priority.  The
effect is that heavily loaded systems may experience some latency
issues.  If this occurs, please create the appropriate configuration
file in /etc/security/limits.d/ as shown below:

cat <<END | sudo tee /etc/security/limits.d/squeak.conf
*      hard    rtprio  2
*      soft    rtprio  2

and report to the squeak mailing list whether this improves behaviour.

You will need to log out and log back in for the limits to take effect.
For more information please see

Am 25.12.20 um 13:55 schrieb Bruce O'Neel:
> So another data point.
> Linux Mint 20 (so basically Ubuntu) on x86-64.  Happens to be a
> MacBook Air but I don't think that's important.
> My normal install only build vm-sound-OSS.  And with that there is no
> sound and a complaint in the terminal about /dev/dsp not existing.
>  Which is true, /dev/dsp does not exist.
> But if install libpluse-dev before I build the VM then I also get
> vm-sound-pluse.
> tmp/opensmalltalk-vm/build.linux64x64/squeak.cog.spur/build/squeak
> <http://squeak.cog.spur/build/squeak> -vm-sound-pulse myimage
> Good news - I get sound!
> Bad news - Well it seems a bit drunk in that it pauses about every
> second to two.  It acts like a buffering issue.  It is slightly worse
> without doing the RT priority limits.conf file.
> I'll also poke at this a bit.
> cheers
> bruce
> /25 December 2020 05:41 tim Rowledge <tim at rowledge.org> wrote:/
>     > On 2020-12-24, at 1:21 PM, Herbert König wrote:
>     >
>     > Ha, ran the script in a terminal and on each piano keypress I get:
>     > sound_Start(default)
>     > soundStart: snd_add_pcm_handler: Function not implemented.
>     That's an error to do with some asynchronous handler stuff in
>     alsa. I have no idea why it would fail.
>     All in all this sound stuff is getting very, very, frustrating
>     tim
>     --
>     tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
>     Strange OpCodes: NOP: Randomize the PSW and then branch
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