28 Aug
2018
28 Aug
'18
10:53 a.m.
Hi,
some things seems to be distro specific and other depend on the used
CPU.
On Mon, 2018-08-27 at 15:58 -0700, Len Ovens wrote:
Some things have changed with cpufreq.
- in days of old there was /etc/rc.d/*ondemand that ran 60 seconds after
startup. This means no matter what you set for cpufreq it gets
down graded 60 sec later. disable ondemand if your os comes with
it.
- Now days there is kernel modules that need to be loaded and effective
before changing cpufreq stuff, otherwise it doesn't work... and
ondemand has been moved to systemd to ensure this. So it is best
if your os uses systemd to move you cpufreq setting script to
systemd to replace ondemand. BTW this ondemand also waits 60
seconds.
Newer Intel CPUs might use 'powersave' instead of 'ondemand' and the
default could be the one chosen by the kernel's config. I still don't
understand this relatively new GOV_SCHEDUTIL thingy, but I didn't have
done any research to learn something about it ;).
Regarding Ubuntu (at least for Xenial) there indeed is 'ondemand' in
/etc/rc.d/, /etc/init.d/. However, I stay with 'powersave' or 'ondemand'
as default and change the governor to 'performance' if I run an audio
session on all of my Linux installs. Batterie charge OTOH might suffer
from 'ondemand'. Thanks to this thread I might understand this
GOV_SCHEDUTIL thingy, INTEL_PSTATE seems to affect the defaults.
"Note: The intel_pstate driver supports only the performance and
powersave governors, but they both provide dynamic scaling. The
performance governor should give better power saving functionality than
the old ondemand governor
[ https://www.phoronix.com/scan.php?page=news_item&px=MTM3NDQ ]."
- https://wiki.archlinux.org/index.php/CPU_frequency_scaling#Scaling_governors
I noticed that 'irqbalance' is there, too.
I don't have a link at hand, but IIRC it shouldn't be used with audio
real-time.
Just in case I run 'sudo apt purge irqbalance' right now, but usually
I'm using Arch where it never was installed.
Regards,
Ralf