documentation: BB_NUMBER_THREADS and PARALLEL_MAKE suggestions

Text that suggests setting the BB_NUMBER_THREADS and
PARALLEL_MAKE variables to speed build time has been updated to
suggest a setting of twice the number of host cores supported.

The 2x number came to light through a discussion on the project
mailing list initiated by Robert P. J. Day.

Reported-by: Robert P. J. Day
(From yocto-docs rev: 1846b41a595b7bd905ca828eaa04112d1533d7a1)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/documentation/poky-ref-manual/ref-variables.xml b/documentation/poky-ref-manual/ref-variables.xml
index 6843094fca..fc4fb9c5b1 100644
--- a/documentation/poky-ref-manual/ref-variables.xml
+++ b/documentation/poky-ref-manual/ref-variables.xml
@@ -927,7 +927,7 @@
                     This variable is usually in the form <filename>-j 4</filename>, where the number
                     represents the maximum number of parallel threads make can run.
                     If you development host supports multiple cores a good rule of thumb is to set 
-                    this variable to one and a half times the number of cores on the host.</para>
+                    this variable to twice the number of cores on the host.</para>
             </glossdef>
         </glossentry>