High DSP in idle status [solved]

Installation & Configuration Linux
#21

I managed to download it, thanks!
I also ordered an adapter to try connecting the sound device to the usb type c socket, then I’ll do some new tests.

#22

I think first investigate if this actually is a problem. Are you sure that the configuration is not taking advantage of more agressive power saving modes which lower CPU clock at idle? Does DSP go above 80% when a session is actually running? I looked through the older posts, I never saw any confirmation that you actually have high DSP useage and underruns while a session is running, only that the DSP looks concerning for an idle session.

#23

It’s great that you have done this test.

I’m sorry to hear about the result, it must be disappointing that the new machine does not work as expected.

I expect that it’ll be very hard to track the actual issue down. It could be anything from USB chipset, graphics cards/driver issues, or bus power-save/frequency scaling. It may also be some issues with the mainboard itself that cannot be configured…

Does this also happen with the internal/onboard soundcard? ie the issue is USB?

#24

There is always the option to buy a separate PCIe USB2 - card. There is no telling if that helps or not.

Edit: I forgot this is a laptop, no option for PCIe - cards.

#25

I don’t know if it matters in this case but you could try booting with the kernel command line parameters intel_idle.max_cstate=0 processor.max_cstate=0 .

It does wonders when it comes to reducing xruns at low latencies .

Here’s some info on the CPU C-States

#26

After XFCE login: clock 3493.300 MHz
After start Jack: clock 3519.477 Mhz, DSP 1-5%
After open Ardour session: clock 3457.470 Mhz, DSP 20-50%
During recording: clock 3433.569 Mhz, DSP 60-90%, many xruns

#27

With internal soundcard I don’t have bad DSP values on idle status. The values ​​fluctuate less and it seems more stable.

#28

It works, I find a reduction of about 10% of DSP but the values continue to fluctuate a lot with many xruns.

Edit: I have done other tests after reboot and now, with this solution, I can stay within 50% of DSP without xruns on recording. It’s good. However, I notice some xruns on qjackctl after stopping the recording.

#29

I did some tests using Guitarix and processor.max_cstate=0 appears to be unnecessary. It’s the intel_idle line that does the magic.

Are you using 2 or 3 buffers/period?
I saw that you didn’t find any improvements using 3 earlier but it seems to be the recommended value and giving the CPU just a little more time should help shaving off the odd xrun.

I would also suggest using at least 64 frames/period, to reduce the risk of xruns even further.
You shouldn’t be able to notice any timing problem using softsynth or guitar effects even at a 44/64/3 setting and if you aren’t using software instruments/amps you may as well set it to 128 frames/period or even higher.

#30

Just out of curiosity: what make and model your laptop is ?

I’m out of ideas, but one more thing comes to mind. Maybe the chipset is not initialized correctly. These kinds of bugs are fixed in EFI, so you should probably install the latest EFI upgrade if one is available.

I tinkered with x42 ALV drums plugin yesterday on my 4 core i7-3630QM laptop and was seeing DSP loads varying from 7 - 60% with nothing else but this one plugin in the session. That seemed much for one plugin so I did some tests. These results might give you some ideas for further testing. Test were done with Alesis IO4 USB sound card, Buffers = 1024, Periods = 3, x42 AVL drums playing drum samples.

Manjaro default kernel 4.19.113, CPU Governor = Powersave, DSP Load 7- 60 %
Edit window mixer strip showing a-compressor that updates volume graphics

Manjaro default kernel 4.19.113, CPU Governor = Powersave, DSP Load 8 - 44 %
No Edit - window mixer strip showing

Manjaro default kernel 4.19.113, CPU Governor = Performance, DSP Load 5 - 56 %
Edit window mixer strip showing a-compressor that updates volume graphics

Manjaro default kernel 4.19.113, CPU Governor = Performance, DSP Load 4 - 40 %
No Edit - window mixer strip showing

Manjaro Realtime kernel 4.19.116-rt45-2, CPU Governor = Powersave, DSP Load 7 - 8.5 %
Edit window mixer strip showing a-compressor that updates volume graphics

Manjaro Realtime kernel 4.19.116-rt45-2, CPU Governor = Powersave, DSP Load 7 - 8.8 %
No Edit - window mixer strip showing

Manjaro Realtime kernel 4.19.116-rt45-2, CPU Governor = Performance, DSP Load 3 - 4.3 %
No Edit - window mixer strip showing

Manjaro Realtime kernel 4.19.116-rt45-2, CPU Governor = Performance, DSP Load 2.9 - 3.5 %
No Edit - window mixer strip showing
Kernel options: intel_idle.max_cstate=0 processor.max_cstate=0

Manjaro Realtime kernel 4.19.116-rt45-2, CPU Governor = Performance, DSP Load 2.8 - 3.4 %
No Edit - window mixer strip showing
Kernel options: intel_idle.max_cstate=0 processor.max_cstate=0 mitigations=off

Conclusion: Realtime kernel gives consistent performance, Performance Governor lowers load.

#31

@peder
probably in the end I will use configurations with higher latency, before I wanted to try to replicate the performance of the older PC.

@mhartzel
My laptop is an Asus N580VD-FI038T with i7 7700HQ cpu.
Thank you for test data, you have high DSP load only with normal kernel, I will do the same test on my system to be sure that the realt time is working properly. Updating the EFI can also be an idea.

#32

I received today the adapter for the usb type c socket, connect the sound card to it i have excellent values, DPS <10% in idle and <40% in recording. I thank everyone for the valuable advice and sign the thread as solved.

Ardour 6: heavy xruns
#33

That is great to hear.
Have fun recording and mixing!

#34

This topic was automatically closed 182 days after the last reply. New replies are no longer allowed.