Re: powerd forgets top CPU frequency ?

From: Bob Bishop <rb_at_gid.co.uk>
Date: Sat, 24 Aug 2024 23:12:13 UTC 
Hi,

> On 24 Aug 2024, at 18:06, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote:
> 
> On T14s thinkpad running:
> 
> FreeBSD critter.freebsd.dk 15.0-CURRENT FreeBSD 15.0-CURRENT #7 main-n271455-a1740cb93639-dirty: Thu Aug  1 09:45:40 UTC 2024     root@critter.freebsd.dk:/critter/obj/critter/FreeBSD/src/amd64.amd64/sys/GENERIC-NODEBUG amd64
> 
> When I run two 100% CPU loaded processes, the machine gradually gets slower and slower, until eventually it limps along at 500-ish MHz rates.
> 
> Killing powerd and starting it again seems to bring the machine back to full speed (for some time).
> 
> Looking at the powerd -v output, my gut feeling is that powerd sometimes looses track of what the (current) top frequency is and thus gradually drags the machine slower or slower...

Possibly buggy ACPI on the Thinkpad not reporting any frequency higher than it’s actually running at?

> I have had a faint feeling for some time that this machine runs significantly faster after a reboot, but I have no observations to support that.
> 
> -- 
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk@FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.

--
Bob Bishop
rb@gid.co.uk