Re: [PATCH v2 0/2] intel_powerclamp: New module parameter

[srinivas pandruvada]

Hi Rui,

On Sun, 2023-02-05 at 15:57 +0000, Zhang, Rui wrote:
> Hi, Srinivas,
> 
> First of all, the previous build error is gone.
> 
> Second, I found something strange, which may be related with the
> scheduler asym-packing, so CC Ricardo.
> 
I thought you disable ITMT before idle injection and reenebale after
removal.



> The test is done with pm linux-intel branch + this patch series on an
> ADL system.
Can you do test on bleeding edge branch of Linux-pm?

>  cpu0~cpu7 are Pcore cpus, cpu8-cpu15 are Ecore cpus, and
> intel_powerclamp is register as cooling_device21.
> 
> 1. run stress -c 16
> 2. update /sys/module/intel_powerclamp/parameters/cpumask
>    echo 90 > /sys/module/intel_powerclamp/parameters/max_idle
> 3. echo 90 > /sys/class/thermal/cooling_device21/cur_state
> 4. echo 0 > /sys/class/thermal/cooling_device21/cur_state
> I use turbostat to monitor the CPU Busy% in all 4 steps.
> 
> If 'cpumask' does not include all the Ecore CPUs, all CPUs becomes
> 100%
> busy after idle injection removed in step 4.
> 
that should be the case.

> If 'cpumask' includes all the Ecore CPUs, i.e. cpumask = FFxy, in
> some
> cases, the Ecore CPUs will drop to an Busy% much lower than 10%, and
> then they don't come back to busy after idle injection removed in
> step
 Do you see that idle injection is removed message in dmesg?
We can also check powercap idle-inejct, if some CPUs still not wake 
from play_idle.


> 4, although we have 16 stress threads. And this also relates with how
> long we stay in idle injection.
> 
> Say, when cpumask=fff3, the problem can be triggered occasionally if
> there is a 10 second timeout between step 3 and step4, but it is much
> easier to reproducible if I increase the timeout to 20 seconds.
> 
> It seems that Pcore can always pull tasks from Ecores, but Ecore can
> not pull tasks from Pcore HT siblings.
> 
That will be regular load balance threads should do.
Better to try upsteam kernel first.

Thanks,
Srinivas


> thanks,
> rui
> 
> On Sat, 2023-02-04 at 18:59 -0800, Srinivas Pandruvada wrote:
> > Split from the series for powerclamp user of powercap idle-inject.
> > 
> > v2
> > - Build warnings reported by Rui
> > - Moved the powerclamp documentation to admin guide folder
> > - Commit log updated as suggested by Rafael and other code
> > suggestion
> > 
> > Srinivas Pandruvada (2):
> >   Documentation:admin-guide: Move intel_powerclamp documentation
> >   thermal/drivers/intel_powerclamp: Add two module parameters
> > 
> >  Documentation/admin-guide/index.rst           |   1 +
> >  .../thermal/intel_powerclamp.rst              |  22 +++
> >  Documentation/driver-api/thermal/index.rst    |   1 -
> >  MAINTAINERS                                   |   1 +
> >  drivers/thermal/intel/intel_powerclamp.c      | 177
> > +++++++++++++++-
> > --
> >  5 files changed, 180 insertions(+), 22 deletions(-)
> >  rename Documentation/{driver-api => admin-
> > guide}/thermal/intel_powerclamp.rst (93%)
> >