[LEDE-DEV] [PATCH] config: add option to select kernel compile optimization type

[Koen Vandeputte]

A lot of targets have more than sufficient space to allow
building the kernel for speed iso size.

Export this performance option to the main config:

- Making it easy accessable for users
- Discarding the need to adjust it in the kernel config each time
when building from scratch and only using "make oldconfig"

Compiling for size is still the default.

Purely informational:

On my cns3xxx board, kernel size increases by ~100kB
but boot time decreased by ~8%.

Signed-off-by: Koen Vandeputte <koen.vandeputte at ncentric.com>
---
 config/Config-kernel.in | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/config/Config-kernel.in b/config/Config-kernel.in
index fa06b5044219..b98c5dd04591 100644
--- a/config/Config-kernel.in
+++ b/config/Config-kernel.in
@@ -194,6 +194,22 @@ config KERNEL_DEBUG_GPIO
 	bool "Compile the kernel with gpio debugging"
 	select KERNEL_DEBUG_KERNEL
 
+config KERNEL_CC_OPTIMIZE_FOR_PERFORMANCE
+        bool
+        default y if COMPILE_KERNEL_FOR_SPEED
+        default n
+
+config KERNEL_CC_OPTIMIZE_FOR_SIZE
+        bool
+        default n if COMPILE_KERNEL_FOR_SPEED
+        default y
+
+config COMPILE_KERNEL_FOR_SPEED
+        bool "Optimize the kernel for speed instead of size"
+        default n
+        help
+          This will compile your kernel for maximum speed (-O2) instead of smaller size (-Os)
+
 config KERNEL_COREDUMP
 	bool
 
-- 
2.7.4