Re: [PATCH] kselftest: cpufreq: Backup and restore governor for sptests

[Yiwei Lin]

On 7/7/2026 1:19 PM, Viresh Kumar wrote:
> On 07-07-26, 00:14, Yiwei Lin wrote:
> > After executing cpufreq sptest, the system governor
> > will be overwritten with the governor switched
> > during the test. Restore this setting to maintain
> > consistency before and after the test.
> >
> > Signed-off-by: Yiwei Lin <s921975628@xxxxxxxxx>
> > ---
> >   tools/testing/selftests/cpufreq/governor.sh   | 21 +++++++++++++++++++
> >   .../selftests/cpufreq/special-tests.sh        | 13 ++++++++++++
> >   2 files changed, 34 insertions(+)
> >
> > diff --git a/tools/testing/selftests/cpufreq/governor.sh b/tools/testing/selftests/cpufreq/governor.sh
> > index fe37df79c0871..5d105ab9c9222 100755
> > --- a/tools/testing/selftests/cpufreq/governor.sh
> > +++ b/tools/testing/selftests/cpufreq/governor.sh
> > @@ -16,6 +16,12 @@ source cpufreq.sh
> >   CUR_GOV=
> >   CUR_FREQ=
> >   
> > +# Per-policy backup, keyed by policy so multiple policies can be saved at once
> > +# (backup_governor/restore_governor also keep CUR_GOV/CUR_FREQ for callers that
> > +# read them directly).
> > +declare -A SAVED_GOVERNORS
> > +declare -A SAVED_FREQS
> > +
> >   # Find governor's directory path
> >   # $1: policy, $2: governor
> >   find_gov_directory()
> > @@ -39,11 +45,13 @@ find_current_governor()
> >   backup_governor()
> >   {
> >   	CUR_GOV=$(find_current_governor $1)
> > +	SAVED_GOVERNORS[$1]=$CUR_GOV
> >   
> >   	printf "Governor backup done for $1: $CUR_GOV\n"
> >   
> >   	if [ $CUR_GOV == "userspace" ]; then
> >   		CUR_FREQ=$(find_current_freq $1)
> > +		SAVED_FREQS[$1]=$CUR_FREQ
> >   		printf "Governor frequency backup done for $1: $CUR_FREQ\n"
> >   	fi
> >   
> > @@ -53,11 +61,13 @@ backup_governor()
> >   # $1: policy
> >   restore_governor()
> >   {
> > +	CUR_GOV=${SAVED_GOVERNORS[$1]}
> >   	__switch_governor $1 $CUR_GOV
> >   
> >   	printf "Governor restored for $1 to $CUR_GOV\n"
> >   
> >   	if [ $CUR_GOV == "userspace" ]; then
> > +		CUR_FREQ=${SAVED_FREQS[$1]}
> >   		set_cpu_frequency $1 $CUR_FREQ
> >   		printf "Governor frequency restored for $1: $CUR_FREQ\n"
> >   	fi
> > @@ -65,6 +75,17 @@ restore_governor()
> >   	printf "\n"
> >   }
> >   
> > +# Save/restore governors for every policy at once
> > +save_all_governors()
> > +{
> > +	for_each_policy backup_governor
> > +}
> > +
> > +restore_all_governors()
> > +{
> > +	for_each_policy restore_governor
> > +}
> > +
> >   # param:
> >   # $1: policy, $2: governor
> >   __switch_governor()
> > diff --git a/tools/testing/selftests/cpufreq/special-tests.sh b/tools/testing/selftests/cpufreq/special-tests.sh
> > index 8d40505dc4682..c7eddadd047d1 100755
> > --- a/tools/testing/selftests/cpufreq/special-tests.sh
> > +++ b/tools/testing/selftests/cpufreq/special-tests.sh
> > @@ -40,7 +40,9 @@ simple_lockdep()
> >   {
> >   	printf "** Test: Running ${FUNCNAME[0]} **\n"
> >   
> > +	save_all_governors
> >   	for_each_policy __simple_lockdep
> > +	restore_all_governors
> >   }
> >   
> >   # Test 2
> > @@ -56,7 +58,10 @@ concurrent_lockdep()
> >   {
> >   	printf "** Test: Running ${FUNCNAME[0]} **\n"
> >   
> > +	save_all_governors
> >   	for_each_policy_concurrent __concurrent_lockdep
> > +	wait
> > +	restore_all_governors
> >   }
> >   
> >   # Test 3
> > @@ -68,17 +73,23 @@ quick_shuffle()
> >   		echo ondemand | sudo tee $CPUFREQROOT/policy*/scaling_governor &
> >   		echo userspace | sudo tee $CPUFREQROOT/policy*/scaling_governor &
> >   	done
> > +	wait
> >   }
> >   
> >   governor_race()
> >   {
> >   	printf "** Test: Running ${FUNCNAME[0]} **\n"
> >   
> > +	save_all_governors
> > +
> >   	# run 8 concurrent instances
> >   	for I in `seq 8`
> >   	do
> >   		quick_shuffle &
> >   	done
> > +	wait
> > +
> > +	restore_all_governors
> >   }
> >   
> >   # Test 4
> > @@ -112,5 +123,7 @@ hotplug_with_updates_cpu()
> >   
> >   hotplug_with_updates()
> >   {
> > +	save_all_governors
> >   	for_each_non_boot_cpu hotplug_with_updates_cpu
> Don't you need wait here too ?
Right. Sorry for missing that there are processes running in the 
background for sptest4. I'll submit the fix for this.
> > +	restore_all_governors
> >   }
>
> Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>