choose python3 from PYTHON3_HOME for benchmarks

Author: timfel

mx.graalpython/mx_graalpython_benchmark.py

@@ -48,6 +48,7 @@
 #
 # ----------------------------------------------------------------------------------------------------------------------
 ENV_PYPY_HOME = "PYPY_HOME"
+ENV_PYTHON3_HOME = "PYTHON3_HOME"
 ENV_JYTHON_JAR = "JYTHON_JAR"
 VM_NAME_GRAALPYTHON = "graalpython"
 VM_NAME_CPYTHON = "cpython"
@@ -231,6 +232,9 @@ def __init__(self, config_name, options=None, env=None, virtualenv=None, iterati
 
     @property
     def interpreter(self):
+        home = mx.get_env(ENV_PYTHON3_HOME)
+        if home:
+            return os.path.join(home, CPythonVm.PYTHON_INTERPRETER)
         if self._virtualenv:
             return os.path.join(self._virtualenv, CPythonVm.PYTHON_INTERPRETER)
         return CPythonVm.PYTHON_INTERPRETER