#956: cpu_affinity([]) can now be used as an alias to set affinity against all eligible CPUs.

1 files changed, 17 insertions, 14 deletions

diff --git a/docs/index.rst b/docs/index.rst
index 5ccc11b3..645df8df 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -1214,32 +1214,35 @@ Process class
 
     Get or set process current
     `CPU affinity <http://www.linuxjournal.com/article/6799?page=0,0>`__.
-    CPU affinity consists in telling the OS to run a certain process on a
-    limited set of CPUs only.
+    CPU affinity consists in telling the OS to run a process on a limited set
+    of CPUs only.
     On Linux this is done via the ``taskset`` command.
-    The number of eligible CPUs can be obtained with
-    ``list(range(psutil.cpu_count()))``.
-    ``ValueError`` will be raised on set in case an invalid CPU number is
-    specified.
+    If no argument is passed it returns the current CPU affinity as a list
+    of integers.
+    If passed it must be a list of integers specifying the new CPUs affinity.
+    If an empty list is passed all eligible CPUs are assumed (and set);
+    on Linux this may not necessarily mean all available CPUs as in
+    ``list(range(psutil.cpu_count()))``).
 
       >>> import psutil
       >>> psutil.cpu_count()
       4
       >>> p = psutil.Process()
-      >>> p.cpu_affinity()  # get
+      >>> # get
+      >>> p.cpu_affinity()
       [0, 1, 2, 3]
-      >>> p.cpu_affinity([0])  # set; from now on, process will run on CPU #0 only
+      >>> # set; from now on, process will run on CPU #0 and #1 only
+      >>> p.cpu_affinity([0, 1])
       >>> p.cpu_affinity()
-      [0]
-      >>>
-      >>> # reset affinity against all CPUs
-      >>> all_cpus = list(range(psutil.cpu_count()))
-      >>> p.cpu_affinity(all_cpus)
-      >>>
+      [0, 1]
+      >>> # reset affinity against all eligible CPUs
+      >>> p.cpu_affinity([])
 
     Availability: Linux, Windows, FreeBSD
 
     .. versionchanged:: 2.2.0 added support for FreeBSD
+    .. versionchanged:: 5.1.0 an empty list can be passed to set affinity
+      against all eligible CPUs.
 
   .. method:: cpu_num()