Fixing CPU resource allocation for new CI (#4525)

* Fixing CPU resource allocation for new CI

* Update ml-agents/mlagents/torch_utils/cpu_utils.py

Co-authored-by: Ervin T. <ervin@unity3d.com>

* [skip ci] testing

* use shares only if on kubernetes

Co-authored-by: Ervin T. <ervin@unity3d.com>

ml-agents/mlagents/torch_utils/cpu_utils.py

     """
     period = _read_in_integer_file("/sys/fs/cgroup/cpu/cpu.cfs_period_us")
     quota = _read_in_integer_file("/sys/fs/cgroup/cpu/cpu.cfs_quota_us")
+    share = _read_in_integer_file("/sys/fs/cgroup/cpu/cpu.shares")
+    is_kubernetes = os.getenv("KUBERNETES_SERVICE_HOST") is not None
+
+    elif period > 0 and share > 0 and is_kubernetes:
+        # In kubernetes, each requested CPU is 1024 CPU shares
+        # https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/#how-pods-with-resource-limits-are-run
+        return int(share // 1024)
     else:
         return os.cpu_count()