rteval: Enforce only one latency measurement module at a time

Latency modules will step on each other's toes if run at the same time
(on the same CPU, though that's an enhancement for later), so only
run one of them.  A priority mechanism allows selecting

Signed-off-by: Crystal Wood <crwood@redhat.com>
Signed-off-by: John Kacur <jkacur@redhat.com>

rteval/modules/__init__.py

diff --git a/rteval/modules/__init__.py b/rteval/modules/__init__.py
index de1ddc4..2a4eafa 100644
--- a/rteval/modules/__init__.py
+++ b/rteval/modules/__init__.py
@@ -40,6 +40,7 @@
                          "finished": threading.Event()}
         self._donotrun = False
         self._exclusive = False
+        self._latency = False
         self.__timestamps = {}
         self.__sleeptime = 2.0
 
@@ -67,6 +68,11 @@
         self._exclusive = True
 
 
+    def set_latency(self):
+        """ Sets the module as an exclusive latency measurer """
+        self._latency = True
+
+
     def set_donotrun(self):
         """ set a module's donotrun field to True """
         self._donotrun = True
@@ -412,9 +418,14 @@
 
         self._logger.log(Log.INFO, f"Preparing {self._module_type} modules")
         exclusive = 0
+        latency = False
         for (modname, mod) in self.__modules:
             if mod.is_exclusive() and mod.WorkloadWillRun():
                 exclusive += 1
+            if mod._latency:
+                if latency:
+                    raise RuntimeError("More than one exclusive latency test")
+                latency = True
         for (modname, mod) in self.__modules:
             if exclusive >= 1:
                 if exclusive != 1:

rteval/modules/measurement/cyclictest.py

diff --git a/rteval/modules/measurement/cyclictest.py b/rteval/modules/measurement/cyclictest.py
index 3a34c1b..a9f5b0c 100644
--- a/rteval/modules/measurement/cyclictest.py
+++ b/rteval/modules/measurement/cyclictest.py
@@ -216,6 +216,7 @@
         self.__started = False
         self.__cyclicoutput = None
         self.__breaktraceval = None
+        self.set_latency()
 
 
     @staticmethod

rteval/modules/measurement/timerlat.py

diff --git a/rteval/modules/measurement/timerlat.py b/rteval/modules/measurement/timerlat.py
index f3bdc70..e4b80c3 100644
--- a/rteval/modules/measurement/timerlat.py
+++ b/rteval/modules/measurement/timerlat.py
@@ -216,6 +216,7 @@
                                                   logfnc=self._log)
         self.__timerlatdata['system'].description = (f"({self.__numcores} cores) ") + info['0']['model name']
         self._log(Log.DEBUG, f"system using {self.__numcores} cpu cores")
+        self.set_latency()
 
 
     def _WorkloadSetup(self):