Use psutil.cpu_count(logical=False) in auto_detect_cpus()

src/xdist/plugin.py

@@ -1,28 +1,13 @@
-import os
 import uuid
 
+import psutil
 import py
 import pytest
 
 
 def auto_detect_cpus():
     try:
-        from os import sched_getaffinity
-    except ImportError:
-        if os.environ.get("TRAVIS") == "true":
-            # workaround https://bitbucket.org/pypy/pypy/issues/2375
-            return 2
-        try:
-            from os import cpu_count
-        except ImportError:
-            from multiprocessing import cpu_count
-    else:
-
-        def cpu_count():
-            return len(sched_getaffinity(0))
-
-    try:
-        n = cpu_count()
+        n = psutil.cpu_count(logical=False)
     except NotImplementedError:
         return 1
     return n if n else 1