It looks as the SoC on the T14s (AMD Ryzen 7 PRO 4750U) doesn’t support
this feature, while grep’ing through my distfiles (i.e. source code of
my programms) indicated some software actually makes use of it.
For more details see e.g.:
- man 7 pkeys
- Documentation/core-api/protection-keys.rst (in the kernel sources)
- https://lwn.net/Articles/643797
- https://www.phoronix.com/scan.php?page=news_item&px=AMD-PRM-PCID-PKEY
This is even worse:
- pcscd keeps being restarted, even with explictly disabling it,
blocking my GPG hw token
- bridge interface setup would require either full systemd networkd
usage (yet I need NetworkManager for VPNs) or disabling most parts
of systemd-networkd (hoping that would work better than with pcscd)
Revert "pygoscelis: Give up, migrate to systemd"
This reverts commit aab957d951f56ff0905b4d0501caba5139aa03ef.
In commit 23eecad7b48913b12bd83917647de99e66d69b49 (2021-10-13) I
lowered the timer frequency from 1 000 Hz to 100 Hz, but while I wasn't
able to recognize a reproducible drop in energy consumption there were
some heavy-load situations when the system started to stutter.
Setting it to 300 Hz as some binary distributions do sounds therfor like
a sane decision.
Trying out a lower time frequency and check if it has any influence at all
after a short discussion in IRC about it.
To me it looks as there is no real impact on my hardware with this
After a debate in IRC and some reading it looks to me as there is no general
rule but many people with opinions. Therefore I don’t expect a difference in
overall power consumption or responsiveness, but will just try it out.
I set up a quick and dirty battery test:
- display brightness at 35 %
- wifi on
- bluetooth off
- some default background deamons running (cron, chrony/NTP, syncthing)
- one termina (konsole) open
- that energy monitor from KDE open
- CPU boost disabled with 'echo 0 > /sys/devices/system/cpu/cpufreq/boost'
- verified that temperatures are low enough that the fan is off
Both setups (5.14.11-T14s with CONFIG_HZ_1000=y vs. 5.14.12-T14s
with CONFIG_HZ_100=y) showed values around 5.6 W, down to 5.2 W, up to > 30W
as I called emerge to check if it's not just a display glitch.
As this is a Notebook I don't have to care at all about some video cards and
TV frequencies that are mentioned in various threads.
To end this commit message I’d like to share a quote that amused me during my
mini-research:
„864Hz is indeed the win - I won't use a kernel wihout that option anymore.”
- User “creidiki”, forums.gentoo.org
