return None if phys cpu count cant' be determined; update HISTORY

2 files changed, 11 insertions, 1 deletions

diff --git a/HISTORY.rst b/HISTORY.rst
index 65cad58e..adf8731c 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -15,6 +15,12 @@ XXXX-XX-XX
 - 694_: [SunOS] cmdline() could be truncated at the 15th character when
   reading it from /proc. An extra effort is made by reading it from process
   address space first.  (patch by Georg Sauthoff)
+- 771_: [Windows] cpu_count() (both logical and physical) return a wrong
+  (smaller) number on systems using process groups (> 64 cores).
+- 771_: [Windows] cpu_times(percpu=True) return fewer CPUs on systems using
+  process groups (> 64 cores).
+- 771_: [Windows] cpu_stats() and cpu_freq() may return incorrect results on
+  systems using process groups (> 64 cores).
 - 1193_: [SunOS] Return uid/gid from /proc/pid/psinfo if there aren't
   enough permissions for /proc/pid/cred.  (patch by Georg Sauthoff)
 - 1194_: [SunOS] Return nice value from psinfo as getpriority() doesn't
diff --git a/psutil/_psutil_windows.c b/psutil/_psutil_windows.c
index 65fc4406..9312125f 100644
--- a/psutil/_psutil_windows.c
+++ b/psutil/_psutil_windows.c
@@ -660,6 +660,7 @@ psutil_cpu_count_phys(PyObject *self, PyObject *args) {
                 }
             }
             else {
+                // TODO: debug message
                 goto return_none;
             }
         }
@@ -677,7 +678,10 @@ psutil_cpu_count_phys(PyObject *self, PyObject *args) {
     }
 
     free(buffer);
-    return Py_BuildValue("I", ncpu);
+    if (ncpus != 0)
+        return Py_BuildValue("I", ncpus);
+    else
+        Py_RETURN_NONE;  // mimick os.cpu_count()
 
 return_none:
     if (buffer != NULL)