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

[Yiwei Lin <s921975628@gmail.com>]

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@gmail.com>
>> ---
>>   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@linaro.org>