lib/oe/utils: allow to set a lower bound on returned cpu_count()

This will be needed for making xz compression more deterministic,
as xz archives are created differently in single- vs multi-threaded
modes.

This means that due to bitbake's default of using as many threads
as there are cores in the system, files compressed with xz
will be different if built on a multi-core system compared to
single-core systems.

Allowing cpu_count() here to return a lower bound, will allow
forcing xz to always use multi-threaded operation.

Signed-off-by: André Draszik <git@andred.net>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/meta/lib/oe/utils.py b/meta/lib/oe/utils.py
index e350b05ddf4882dd780829afce91ad1df33ebf9a..aee433648204b3afa0441e2b9bc4dfe70523b7c4 100644 (file)
--- a/meta/lib/oe/utils.py
+++ b/meta/lib/oe/utils.py
@@ -248,9 +248,10 @@ def trim_version(version, num_parts=2):
     trimmed = ".".join(parts[:num_parts])
     return trimmed
 
-def cpu_count():
+def cpu_count(at_least=1):
     import multiprocessing
-    return multiprocessing.cpu_count()
+    cpus = multiprocessing.cpu_count()
+    return max(cpus, at_least)
 
 def execute_pre_post_process(d, cmds):
     if cmds is None: