[LAU] performance problems after kernel/microcode update ?

Tim termtech at rogers.com
Fri Sep 14 01:13:12 CEST 2018



On 09/13/2018 05:26 PM, Niklas Reppel wrote:
> Hi,
> 
> i recently updated my Arch linux system, to to the following version:
> 
> Linux 4.18.6-arch1-1-ARCH #1 SMP PREEMPT
> 
> Afterwards, i noticed that something has changed regarding the realtime 
> permissions
> and that i had to install a new package called 'realtime-priviliges', 
> which i never needed before,
> and subsequently add my main user to the 'realtime' group.
> 
> In that wake, i updated the processor microcode, which i didn't use at 
> all before (there always was some
> error message during bootup, but nothing else).
> 
> After being able to start JACK in realtime again, i felt that there was 
> a significant loss of performance.
> Things that didn't cause any dropouts before now start to crackle and 
> gristle (as a sidenote, i mostly
> use SuperCollider to make sound).
> 
> Also, and this puzzled me especially, there were dropouts, but no XRuns 
> ... normally, when i push the
> system to the limits, i get XRuns, that'd be expected. But now, it's 
> dropouts without, and they start way
> earlier.
> 
> My machine has an Intel(R) Core(TM) i7-4600U CPU @ 2.10GHz Processor if 
> that info is of user for anyone ...
> 
> Anybody else noticed something like that recently ?
> 
> Best,
> nik
> 

Hello, I always reply when I hear of crackles, pops, and dropouts
  because it took me several months to figure out my problem with that.
Maybe it will help.

Here is the latest time I replied, a month ago, please scroll down:

http://linux-audio.4202.n7.nabble.com/M-Audio-Fast-Track-Pro-unreliable-distorted-recording-td89125i20.html#a106829

Long story short: Try running with only one processor core active.

It completely cured my problem, and another user's as well.
In my case the device is a PCI M-Audio delta1010, and in the
  other user's case it was a similar ice1712-based card.
However in the above Fast-Track-Pro case, that's USB and we
  don't yet know if the trick solved that user's problem...

Be patient: If the number of CPU cores is the cause it may take
  several minutes for the crackling to appear since I believe what
  happens is that some low-level 'counters/pointers' which should
  always be in sync slowly approach and 'pass' each other, and that's
  when the noise occurs.

In my case the very same symptom occurred in Windows.
That proved beyond doubt that it was a hardware issue.

Hope that helps.
Tim.


More information about the Linux-audio-user mailing list