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 <s921975...@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.ku...@linaro.org>