[LAU] performance problems after kernel/microcode update ?

[David W. Jones]

On September 13, 2018 1:13:12 PM HST, Tim <termtech at rogers.com> wrote:
> 
> 
> 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.

While I, on the other hand, use all cores (real and hyperthread) on my i7 with no crackles or distorted recordings and such at all. Same for the 4 real cores on my AMD desktop system.

In my opinion, most PC motherboards weren't designed with any audio thought beyond including an on-board audio chip.

--
David W. Jones
gnome at hawaii.rr.com
authenticity, honesty, community
http://dancingtreefrog.com

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