bitbake: utils: better estimate number of available cpus

When running in a cgroup which is limited to a subset of cpus (via
cpuset.cpus), cpu_count() should return the number of cpus that can be
used instead of the number of cpus the system has.

This also aligns the semantics with nproc.

(Bitbake rev: a029bfe96c6542f178720c72a772b7ede9898118)

Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/bitbake/lib/bb/utils.py b/bitbake/lib/bb/utils.py
index ad13d04331..ebee65d3dd 100644
--- a/bitbake/lib/bb/utils.py
+++ b/bitbake/lib/bb/utils.py
@@ -1142,7 +1142,10 @@ def get_referenced_vars(start_expr, d):
 
 
 def cpu_count():
-    return multiprocessing.cpu_count()
+    try:
+        return len(os.sched_getaffinity(0))
+    except OSError:
+        return multiprocessing.cpu_count()
 
 def nonblockingfd(fd):
     fcntl.fcntl(fd, fcntl.F_SETFL, fcntl.fcntl(fd, fcntl.F_GETFL) | os.O_NONBLOCK)