[ubuntu-studio-devel] Possible explanation of my problems with Ubuntu Studio 18.10 and video may require more than 768MB in some cases

[Len Ovens]

On Wed, 5 Dec 2018, Mike Squires wrote:

> First, it seems that I need at least 768MB and very likely 1GB of memory 
> on the video board to avoid the problems I had with the 256MB 
> All-In-Wonder Radeon board I used previously.  Displays are two HD 
> displays; I couldn't display some windows, such as "Terminal Emulator", 
> over the right-hand two-thirds of the second monitor.  With a 1GB card, 
> no problem.

Ok. That does sound odd. I haven't had that problem with only an i5 using 
default video (intel on chip) with dual monitors.

> However, the system was incredibly slow.
>
> After login all functions were very slow; for example, burning a DVD ran 
> at less than 1X where the same hardware runs at more than 7x using 
> 16.04.  The system was unable to keep the buffers filled, with 16.04 
> that is not a problem.

Yikes! have you tried ctl-alt-F1 from the login screen and do SW upgrade 
from there? is it any faster?

> A clue, I think, is that the "wa" (processes in wait state) percentage 
> in "top" stood at more than 30% all of the time; currently running 16.04 
> on the same hardware it is 0.0 to 0.2%.

OK.

> Running the version of XUBUNTU which is the base for 18.04 didn't show 
> this issue (running from the DVD).

Hmm, then maybe try installing the generic linux kernel alongside and run 
that to see what happens. You may wish to chmod -x 
/etc/grub.d/09_lowlatency first though so that you don't default to 
lowlatency.
Of course I would really like to know if adding lowlatency kernel to 
Xubuntu kills that too. It may be something else we do that Xubuntu has 
found and fixed that we haven't that has caused that... or one of the 
tweaks we have added besides the extra kernel.

> My guess is that there is something about the low-latency kernel that 
> causes my dual Xeon quad core to slow down dramatically.  I wonder if it

That _should_ be faster than my i5 for sure.

The fact that you are running an ice1712 audio card suggests that you do 
audio work where the lowlatency may be important. I should ask anyway, how 
you use the machine. If you are doing recording with external monitoring 
and can run with a higher latency the generic kernel may work fine for 
you.

I have purposely stayed with the intel video because I know that the 
drivers are "open" and just work with most kernels (or get fixed pretty 
quick). I understand though that the xeon chips just don't have that 
option. (last I looked) I have next to no experience dealing with other 
video types.

BTW have you tried 18.04?

The differences from generic to lowlatency is very small (one switch that 
can actually be turned on in generic at boot time I am told).

--
Len Ovens
www.ovenwerks.net