[gentoo-portage-dev] [PATCH v2] Default MAKEOPTS to -j(ncpus+1) when unset

["Michał Górny" <mgorny@gentoo.org>]

Default MAKEOPTS job number to (number of CPUs + 1) when it is not
provided in the ebuild environment.

Suggested-By: Daniel Robbins <drobbins@funtoo.org>
---
 pym/portage/package/ebuild/doebuild.py |  8 +++++++-
 pym/portage/util/cpuinfo.py            | 18 ++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 pym/portage/util/cpuinfo.py

diff --git a/pym/portage/package/ebuild/doebuild.py b/pym/portage/package/ebuild/doebuild.py
index bf97660..f43dddc 100644
--- a/pym/portage/package/ebuild/doebuild.py
+++ b/pym/portage/package/ebuild/doebuild.py
@@ -1,4 +1,4 @@
-# Copyright 2010-2013 Gentoo Foundation
+# Copyright 2010-2015 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 from __future__ import unicode_literals
@@ -66,6 +66,7 @@ from portage.package.ebuild.prepare_build_dirs import prepare_build_dirs
 from portage.util import apply_recursive_permissions, \
 	apply_secpass_permissions, noiselimit, normalize_path, \
 	writemsg, writemsg_stdout, write_atomic
+from portage.util.cpuinfo import get_cpu_count
 from portage.util.lafilefixer import rewrite_lafile	
 from portage.versions import _pkgsplit
 from _emerge.BinpkgEnvExtractor import BinpkgEnvExtractor
@@ -463,6 +464,11 @@ def doebuild_environment(myebuild, mydo, myroot=None, settings=None,
 				mysettings["PATH"] = os.path.join(os.sep, eprefix_lstrip,
 					 "usr", libdir, "ccache", "bin") + ":" + mysettings["PATH"]
 
+		if 'MAKEOPTS' not in mysettings:
+			nproc = get_cpu_count()
+			if nproc:
+				mysettings['MAKEOPTS'] = '-j%d' % (nproc + 1)
+
 		if not eapi_exports_KV(eapi):
 			# Discard KV for EAPIs that don't support it. Cached KV is restored
 			# from the backupenv whenever config.reset() is called.
diff --git a/pym/portage/util/cpuinfo.py b/pym/portage/util/cpuinfo.py
new file mode 100644
index 0000000..669e707
--- /dev/null
+++ b/pym/portage/util/cpuinfo.py
@@ -0,0 +1,18 @@
+# Copyright 2015 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+__all__ = ['get_cpu_count']
+
+
+def get_cpu_count():
+	"""
+	Try to obtain the number of CPUs available.
+
+	@return: Number of CPUs or None if unable to obtain.
+	"""
+
+	try:
+		import multiprocessing
+		return multiprocessing.cpu_count()
+	except (ImportError, NotImplementedError):
+		return None
-- 
2.2.1