From ef5fc76d0e31a1b73ca03190b72ebe4410f42ae8 Mon Sep 17 00:00:00 2001
From: Juri Lelli <juri.lelli@redhat.com>
Date: Wed, 13 Jun 2018 09:51:09 +0200
Subject: [PATCH] libs/rtapp: Make cpufreq module optional for rt-app
 calibration

If cpufreq module is not used (e.g., KVM target) rt-app calibration
should still work as usual, no need to set frequency to max in this case
though.

Remove the hard dependecy towards cpufreq module.

Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
---
 libs/wlgen/wlgen/rta.py | 51 ++++++++++++++++++++++++++++-------------
 1 file changed, 35 insertions(+), 16 deletions(-)

diff --git a/libs/wlgen/wlgen/rta.py b/libs/wlgen/wlgen/rta.py
index b26328b37..32f50109d 100644
--- a/libs/wlgen/wlgen/rta.py
+++ b/libs/wlgen/wlgen/rta.py
@@ -101,6 +101,39 @@ class RTA(Workload):
         # Setup RTA callbacks
         self.setCallback('postrun', self.__postrun)
 
+    @staticmethod
+    def __setGovernorsPerformance(target):
+        if 'cpufreq' not in target.modules:
+            log = logging.getLogger('RTApp')
+            log.warning('cpufreq module not loaded,'
+                        ' skipping setting frequency to max')
+            return {}
+
+        # Save previous governors
+        old_governors = {}
+        for domain in target.cpufreq.iter_domains():
+            cpu = domain[0]
+            governor = target.cpufreq.get_governor(cpu)
+            tunables = target.cpufreq.get_governor_tunables(cpu)
+            old_governors[cpu] = governor, tunables
+
+        target.cpufreq.set_all_governors('performance')
+
+        return old_governors
+
+    @staticmethod
+    def __restoreGovernors(target, old_governors):
+        if 'cpufreq' not in target.modules:
+            return
+
+        # Restore previous governors
+        #   Setting a governor & tunables for a cpu will set them for all cpus
+        #   in the same clock domain, so only restoring them for one cpu
+        #   per domain is enough to restore them all.
+        for cpu, (governor, tunables) in old_governors.iteritems():
+            target.cpufreq.set_governor(cpu, governor)
+            target.cpufreq.set_governor_tunables(cpu, **tunables)
+
     @staticmethod
     def calibrate(target):
         """
@@ -115,15 +148,7 @@ class RTA(Workload):
         # Setup logging
         log = logging.getLogger('RTApp')
 
-        # Save previous governors
-        old_governors = {}
-        for domain in target.cpufreq.iter_domains():
-            cpu = domain[0]
-            governor = target.cpufreq.get_governor(cpu)
-            tunables = target.cpufreq.get_governor_tunables(cpu)
-            old_governors[cpu] = governor, tunables
-
-        target.cpufreq.set_all_governors('performance')
+        old_governors = RTA.__setGovernorsPerformance(target)
 
         # Create calibration task
         max_rtprio = int(target.execute('ulimit -Hr').split('\r')[0])
@@ -154,13 +179,7 @@ class RTA(Workload):
                 pload[cpu] = int(pload_match.group(1))
                 log.debug('>>> cpu%d: %d', cpu, pload[cpu])
 
-        # Restore previous governors
-        #   Setting a governor & tunables for a cpu will set them for all cpus
-        #   in the same clock domain, so only restoring them for one cpu
-        #   per domain is enough to restore them all.
-        for cpu, (governor, tunables) in old_governors.iteritems():
-            target.cpufreq.set_governor(cpu, governor)
-            target.cpufreq.set_governor_tunables(cpu, **tunables)
+        RTA.__restoreGovernors(target, old_governors)
 
         log.info('Target RT-App calibration:')
         log.info("{" + ", ".join('"%r": %r' % (key, pload[key])
-- 
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