Merge branch 'chandan/fix-cpu-count' into 'master'

_platform: Don't use psutil.Process.cpu_affinity on unsupported platforms

Closes #1244

See merge request BuildStream/buildstream!1786

2 files changed, 9 insertions, 9 deletions

diff --git a/src/buildstream/_platform/darwin.py b/src/buildstream/_platform/darwin.py
index 06491e8b4..2e244557e 100644
--- a/src/buildstream/_platform/darwin.py
+++ b/src/buildstream/_platform/darwin.py
@@ -15,7 +15,6 @@
 #  You should have received a copy of the GNU Lesser General Public
 #  License along with this library. If not, see <http://www.gnu.org/licenses/>.
 
-import os
 import resource
 
 from ..sandbox import SandboxDummy
@@ -28,13 +27,6 @@ class Darwin(Platform):
     # This value comes from OPEN_MAX in syslimits.h
     OPEN_MAX = 10240
 
-    def get_cpu_count(self, cap=None):
-        cpu_count = os.cpu_count()
-        if cap is None:
-            return cpu_count
-        else:
-            return min(cpu_count, cap)
-
     def maximize_open_file_limit(self):
         # Note that on Mac OSX, you may not be able to simply set the soft
         # limit to the reported hard limit, as it may not be the only limit in
diff --git a/src/buildstream/_platform/platform.py b/src/buildstream/_platform/platform.py
index b58ae3e3d..c838ef6c2 100644
--- a/src/buildstream/_platform/platform.py
+++ b/src/buildstream/_platform/platform.py
@@ -122,7 +122,15 @@ class Platform:
         return PlatformImpl(force_sandbox=force_sandbox)
 
     def get_cpu_count(self, cap=None):
-        cpu_count = len(psutil.Process().cpu_affinity())
+        # `psutil.Process.cpu_affinity()` is not available on all platforms.
+        # So, fallback to getting the total cpu count in cases where it is not
+        # available.
+        dummy_process = psutil.Process()
+        if hasattr(dummy_process, "cpu_affinity"):
+            cpu_count = len(dummy_process.cpu_affinity())
+        else:
+            cpu_count = os.cpu_count()
+
         if cap is None:
             return cpu_count
         else: