[PATCH v2] cpupower: Add support for setting EPP via systemd service

[Jan Kiszka <jan.kiszka@siemens.com>]

From: Jan Kiszka <jan.kiszka@siemens.com>

Extend the systemd service so that it can be used for tuning the Energy
Performance Preference (EPP) as well. Available options can be read from
/sys/devices/system/cpu/cpufreq/policy0/energy_performance_available_preferences.
The desired one can then be set in cpupower-service.conf.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---

Changes in v2:
 - improve commit message

 tools/power/cpupower/cpupower-service.conf | 5 +++++
 tools/power/cpupower/cpupower.sh           | 6 ++++++
 2 files changed, 11 insertions(+)

diff --git a/tools/power/cpupower/cpupower-service.conf b/tools/power/cpupower/cpupower-service.conf
index 02eabe8e3614..abbb46967565 100644
--- a/tools/power/cpupower/cpupower-service.conf
+++ b/tools/power/cpupower/cpupower-service.conf
@@ -30,3 +30,8 @@
 # its policy for the relative importance of performance versus energy savings to
 # the processor. See man CPUPOWER-SET(1) for additional details
 #PERF_BIAS=
+
+# Set the Energy Performance Preference
+# Available options can be read from
+# /sys/devices/system/cpu/cpufreq/policy0/energy_performance_available_preferences
+#EPP=
diff --git a/tools/power/cpupower/cpupower.sh b/tools/power/cpupower/cpupower.sh
index a37dd4cfdb2b..6283e8bf275d 100644
--- a/tools/power/cpupower/cpupower.sh
+++ b/tools/power/cpupower/cpupower.sh
@@ -23,4 +23,10 @@ then
     cpupower set -b "$PERF_BIAS" > /dev/null || ESTATUS=1
 fi
 
+# apply Energy Performance Preference
+if test -n "$EPP"
+then
+    cpupower set -e "$EPP" > /dev/null || ESTATUS=1
+fi
+
 exit $ESTATUS
-- 
2.47.3