[PATCH] local.conf.sample: Add automatic defaults for BB_NUMBER_THREADS and PARALLEL_MAKE

[Richard Purdie <richard.purdie@linuxfoundation.org>]

Its rather sad that people don't appear to read local.conf and then complain
about slow builds when they're just using a single thread. Most systems have
more than one core now so we might as well use a more automatic default
for these values. This may lead to better experiences for new users.

[YOCTO #2528]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
---
diff --git a/meta/conf/local.conf.sample b/meta/conf/local.conf.sample
index 71856b8..36d33e1 100644
--- a/meta/conf/local.conf.sample
+++ b/meta/conf/local.conf.sample
@@ -18,12 +18,18 @@
 # option determines how many tasks bitbake should run in parallel:
 #
 #BB_NUMBER_THREADS ?= "4"
+#
+# Default to setting automatically based on cpu count
+BB_NUMBER_THREADS ?= "${@oe.utils.cpu_count()}"
 # 
 # The second option controls how many processes make should run in parallel when
 # running compile tasks:
 #
 #PARALLEL_MAKE ?= "-j 4"
 #
+# Default to setting automatically based on cpu count
+PARALLEL_MAKE ?= "-j ${@oe.utils.cpu_count()}"
+#
 # For a quad-core machine, BB_NUMBER_THREADS = "4", PARALLEL_MAKE = "-j 4" would
 # be appropriate for example.