Hi Niklas,
On 2018-09-13 23:26:30 (+0200), 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.
Please subscribe
to the arch-proaudio mailing list. The change was
announced there [1].
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 ?
It is very likely that the
changes introduced to the Linux Kernel in
response to the spectre and meltdown security issues are causing this
in combination with (known to be) performance degrading Intel ucode.
However, I would not advice you to disable mitigations such as page
table isolation (PTI), unless you know about the implied risks!
Best,
David
[1]
https://lists.archlinux.org/pipermail/arch-proaudio/2018-August/000191.html
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