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Re: Governor problem with generic 6.1 arm64 kernel on Raspberry



Sure I can write it in a script.. as you're using bash, there you go....

https://pastebin.com/4BtgHfjW

As some of the /sys files are readable only by root, start it with sudo. When the governor works correct, the CPU freq should follow the scaling_freq, it may vary due to timing and other things.

-Alex


On Wed, 2024-03-20 at 08:43 -0500, Hank Barta wrote:
I'll give it a try.

hbarta@cm4iob:~/bin$ cd /sys/devices/system/cpu/cpufreq/policy0/
hbarta@cm4iob:/sys/devices/system/cpu/cpufreq/policy0$ cat scaling_driver scaling_governor
cpufreq-dt
schedutil
hbarta@cm4iob:/sys/devices/system/cpu/cpufreq/policy0$ cpufreq-dt
-bash: cpufreq-dt: command not found
hbarta@cm4iob:/sys/devices/system/cpu/cpufreq/policy0$ schedutil
-bash: schedutil: command not found
hbarta@cm4iob:/sys/devices/system/cpu/cpufreq/policy0$ foreach i ( `seq 1 1 10` )
-bash: syntax error near unexpected token `('
hbarta@cm4iob:/sys/devices/system/cpu/cpufreq/policy0$


Can I suggest you provide a script to report the readings that works with Debian? It would be great if you could put it somewhere like Github or Pastebin?

This is Debian Bookworm (not updated recently as I don't normally run this.) I can run your tests before and after an upgrade. At present this host is running

Linux cm4iob 6.1.0-18-arm64 #1 SMP Debian 6.1.76-1 (2024-02-01) aarch64 GNU/Linux



On Wed, Mar 20, 2024 at 5:53 AM Alex <sokoloff@e-mail.de> wrote:
> That latest kernel I referred to is .76, not 69, sorry for the
> confusion.
>
> On Wed, 2024-03-20 at 11:48 +0100, Alex wrote:
> > Hi,
> >
> > Is there really no one who could and would just do that one test
> > for
> > me? I reproduced the problem with the actual 6.1.69 kernel from the
> > Debian repository.
> >
> > 1. Boot a Rasyberry Pi 4 without X or other graphics running. Check
> > if
> > scaling_cur_freq and cpuinfo_cur_freq are in line. You also could
> > query
> > by Raspberry userland (vcgencmd measure_clock arm), which is in my
> > case
> > always identical to cpuinfo_cur_freq.
> >
> >
> > alex@aws:~:(6)> cd /sys/devices/system/cpu/cpufreq/policy0/
> > alex@aws:cpu/cpufreq/policy0:(4)> cat scaling_driver
> > scaling_governor
> > cpufreq-dt
> > schedutil
> > alex@aws:cpu/cpufreq/policy0:(5)> foreach i ( `seq 1 1 10` )
> > foreach? date +%H:%M:%S
> > foreach? sudo cat scaling_cur_freq cpuinfo_cur_freq
> > foreach? echo --- ; sleep 2
> > foreach? end
> > 10:41:31
> > 1300000
> > 1300000
> > ---
> > 10:41:33
> > 900000
> > 1500000
> > ---
> > 10:41:35
> > 1800000
> > 1800000
> > ---
> > 10:41:37
> > 1800000
> > 1300000
> > ---
> > 10:41:39
> > 1300000
> > 1300000
> >
> > 3. Start Xorg server. I just found the latest generic kernel build
> > from
> > the debian repository supports kms and accelerated X, which is a
> > great
> > achievement, by the way.
> >
> > Repeat the tests. In my use case the cpuinfo_cur_freq is now always
> > identical to cpuinfo_max_freq, no matter what scaling_cur_freq
> > gives
> > back. vcgencmd via /dev/vcio also reports the max speed.
> >
> > 4. Shut that X server down again and re-check. In my setup the
> > governor
> > (no matter which one you choose) will not go back working again. 
> >
> > Thanks,
> > Alex
> >
> > On Wed, 2024-03-13 at 22:39 +0100, Alex wrote:
> > > I have to admit that I drew the wrong conclusions. Some of my
> > > frequency readings were conducted within an x-terminal, some on a
> > > console screen, without X running. That, in fact, seemed to make
> > > the
> > > difference.
> > >
> > > Booting in any of the 6.1 upstream generic kernels works fine,
> > > including the governor, as long as I remained in text mode. Also
> > > switching between different governors immediately brought the
> > > intended result. 
> > >
> > > Once starting the X Server (X.Org 1.20.11 with either fbdev or
> > > fbturbo driver) causes the CPU frequency not following the
> > > scaling
> > > frequency any more but stick to the maximum speed defined as per
> > > firmware or config.txt. Shutting down the X server does not
> > > revert
> > > this.
> > >
> > > For me this seems to be a gpu related issue ... ?
> > >
> > > Regards,
> > > Alex
> > >
> > >
> > > On Wed, 2024-03-13 at 14:27 +0100, Alex wrote:
> > > > >
> > > >
> > > > There was a typo in my last statement...
> > > >
> > > > > oldstable 5.10 --> governor *is* working
> > > > > oldstable 6.1 backport --> governor not working
> > > > > oldstable 6.1 RT backport --> governor is working
> > > > > stable 6.1 --> governor is working
> > > >
> > > >
> > > > On Wed, 2024-03-13 at 13:41 +0100, Alex wrote:
> > > > > Hi Andy,
> > > > >
> > > > > I see your point... however the governor working or not seems
> > > > > to
> > > > > be a
> > > > > pure kernel issue, and Devuan does not support any arm
> > > > > platform
> > > > > and
> > > > > not build the generic kernels in the apt repository. Their
> > > > > repository
> > > > > is mainly fed from Debian one, with some changes when it
> > > > > comes
> > > > > to
> > > > > systemd vs. init.
> > > > >
> > > > > There are prebuilt images for arm64 with custom compiled
> > > > > kernels
> > > > > without any method to do regular updates (they do not feed
> > > > > these
> > > > > kernels to the apt repository). This is why I ended in
> > > > > compiling
> > > > > the
> > > > > kernel by myself in the first place. 
> > > > >
> > > > > However, to be sure it really is a kernel issue I gave
> > > > > 20231109_raspi_4_bookworm.img an try today and the governor
> > > > > worked.
> > > > > So I installed the 6.1 kernel from the stable repository on
> > > > > my
> > > > > oldstable Devuan userland and still, the governor works.
> > > > >
> > > > > So, there seems to be a difference between the 6.1 oldstable
> > > > > backport
> > > > > kernels vs. the ones in the stable repository.
> > > > >
> > > > > My first posts primary intention was not to get support (as I
> > > > > do
> > > > > have
> > > > > a running system), but to point out a possible bug which is
> > > > > present
> > > > > in some Debian arm64 kernels, while others are working fine.
> > > > >
> > > > > oldstable 5.10 --> governor not working
> > > > > oldstable 6.1 backport --> governor not working
> > > > > oldstable 6.1 RT backport --> governor working
> > > > > stable 6.1 --> governor working
> > > > >
> > > > > So after all, this does not seem to be a Devuan issue. I'd be
> > > > > glad to
> > > > > help tracking down this issue.
> > > > >
> > > > > Alex
> > > > >
> > > > > On Tue, 2024-03-12 at 22:26 +0000, Andrew M.A. Cater wrote:
> > > > > > On Tue, Mar 12, 2024 at 11:14:10AM +0100, Alex wrote:
> > > > > > > Hi there,
> > > > > > >
> > > > > > > I am running a Raspberry Pi 4 with an oldstable release
> > > > > > > for
> > > > > > > a
> > > > > > > few
> > > > > > > years
> > > > > > > now. In fact, it is Devuan Chimaera, corresponding to
> > > > > > > Debian
> > > > > > > 11
> > > > > > > Bookworm without systemd. As the kernel images comes
> > > > > > > straight
> > > > > > > from
> > > > > > > Debian, I am reporting it here...
> > > > > > >
> > > > > >
> > > > > > Can I respectfully suggest that you ask Devuan for help?
> > > > > >
> > > > > > if you use the images at raspi.debian.net, we may be able
> > > > > > to
> > > > > > help
> > > > > > you.
> > > > > > If you want to try booting using UEFI and a stock Debian
> > > > > > image,
> > > > > > we
> > > > > > can also offer advice.
> > > > > >
> > > > > > For Devuan - we cannot be entirely sure that the advice we
> > > > > > give
> > > > > > will
> > > > > > be correct.
> > > > > >
> > > > > > With every good wish, as ever,
> > > > > >
> > > > > > Andy
> > > > > >
> > > > > > > Alex
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> >
>
>




--
Beautiful Sunny Winfield


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