On Thu, Oct 28, 2021 at 7:29 PM Rafael J. Wysocki [off-list ref] wrote:

On Thu, Oct 28, 2021 at 7:10 PM Julia Lawall [off-list ref] wrote:

quoted

quoted

Now, for your graph 3, are you saying this pseudo
code of the process is repeatable?:

Power up the system, booting kernel 5.9
switch to passive/schedutil.
wait X minutes for system to settle
do benchmark, result ~13 seconds
re-boot to kernel 5.15-RC
switch to passive/schedutil.
wait X minutes for system to settle
do benchmark, result ~40 seconds
re-boot to kernel 5.9
switch to passive/schedutil.
wait X minutes for system to settle
do benchmark, result ~28 seconds

In the first boot of 5.9, the des (desired?) field of the HWP_REQUEST
register is 0 and in the second boot (after booting 5.15 and entering
passive mode) it is 10.  I don't know though if this is a bug or a
feature...

It looks like a bug.

I think that the desired value is not cleared on driver exit which
should happen.  Let me see if I can do a quick patch for that.

Please check the behavior with the attached patch applied.