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* [PATCH] kselftest: cpufreq: Backup and restore governor for sptests
@ 2026-07-06 16:14 Yiwei Lin
  2026-07-07  5:19 ` Viresh Kumar
  0 siblings, 1 reply; 2+ messages in thread
From: Yiwei Lin @ 2026-07-06 16:14 UTC (permalink / raw)
  To: rafael, viresh.kumar, shuah
  Cc: linux-pm, linux-kselftest, linux-kernel, Yiwei Lin

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
+	restore_all_governors
 }
-- 
2.34.1


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2026-07-06 16:14 [PATCH] kselftest: cpufreq: Backup and restore governor for sptests Yiwei Lin
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