build: turn on package parallel builds by default and fix descriptions.

By default, this is only used when building with make -j.

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@33582 3c298f89-4303-0410-b956-a3cf2f4a3e73

diff --git a/Config.in b/Config.in
index e5b3346..bd4f63e 100644 (file)
--- a/Config.in
+++ b/Config.in
@@ -296,23 +296,12 @@ menu "Global build settings"
        config PKG_BUILD_PARALLEL
                bool
                prompt "Compile certain packages parallelized"
        config PKG_BUILD_PARALLEL
                bool
                prompt "Compile certain packages parallelized"

-               default n
+               default y

                help
                  This adds a -jX option to certain packages that are known to
                help
                  This adds a -jX option to certain packages that are known to

-                 behave well for parallel build.
-
-                 Note that this may overcommit CPU resources depending on the
-                 -j level of the main make process, the number of package
-                 submake jobs selected below and the number of actual CPUs present.
-                 Example: If the main make is passed a -j4 and the submake -j
-                 is also set to 4, we may end up with 16 parallel make processes
-                 in the worst case.
-
-                 You get maximum build performance, if you set the package build
-                 jobs to the number of CPUs (cores) available and also start the main
-                 make process with -jX, where X is the number of CPUs (cores).
-                 However, make sure you have enough RAM available for
-                 NR_CPUS to the power of two (NR_CPUS^2) make jobs.
+                 behave well for parallel build. By default the package make processes
+                 use the main jobserver, in which case this option only takes effect
+                 when you add -jX to the make command.

 
                  If you are unsure, select N.
 
 
                  If you are unsure, select N.
 


@@ -325,6 +314,14 @@ menu "Global build settings"
                  This passes the main make process jobserver fds to package builds,
                  enabling full parallelization across different packages
 
                  This passes the main make process jobserver fds to package builds,
                  enabling full parallelization across different packages
 

+                 Note that disabling this may overcommit CPU resources depending on the
+                 -j level of the main make process, the number of package
+                 submake jobs selected below and the number of actual CPUs present.
+                 Example: If the main make is passed a -j4 and the submake -j
+                 is also set to 4, we may end up with 16 parallel make processes
+                 in the worst case.
+
+

        config PKG_BUILD_JOBS
                int
                prompt "Number of package submake jobs (2-512)"
        config PKG_BUILD_JOBS
                int
                prompt "Number of package submake jobs (2-512)"