Feature: Make default C-EDF clustering compile-time configurable.wip-default-clustering

Prior to this patch, C-EDF defaulted to clustering around the L2 cache.
This is a poor choice for a system with Nahalem-EX processors, where
L2 caches are private to each core and the L3 is the only shared cache.

This patch makes the default C-EDF clustering configurable at compile-time.
Kconfig makes L2 the default selection (in spirit with the prior C-EDF
default).

2 files changed, 29 insertions, 0 deletions

diff --git a/litmus/Kconfig b/litmus/Kconfig
index a2f267870f29..febc11552bd1 100644
--- a/litmus/Kconfig
+++ b/litmus/Kconfig
@@ -12,6 +12,27 @@ config PLUGIN_CEDF
           On smaller platforms (e.g., ARM PB11MPCore), using C-EDF
           makes little sense since there aren't any shared caches.
 
+choice
+        prompt "Default C-EDF Clustering"
+        depends on PLUGIN_CEDF
+        default DEFAULT_L2
+        help
+          Select the default C-EDF clustering: L1 (P-EDF), L2, L3, ALL (G-EDF)
+
+        config CEDF_DEFAULT_L1
+                bool "L1"
+
+        config CEDF_DEFAULT_L2
+                bool "L2"
+
+        config CEDF_DEFAULT_L3
+                bool "L3"
+
+        config CEDF_DEFAULT_ALL
+                bool "All"
+
+endchoice
+
 config PLUGIN_PFAIR
         bool "PFAIR"
         depends on HIGH_RES_TIMERS && !NO_HZ
diff --git a/litmus/sched_cedf.c b/litmus/sched_cedf.c
index 8c9513d33f59..1469a1e537d3 100644
--- a/litmus/sched_cedf.c
+++ b/litmus/sched_cedf.c
@@ -50,7 +50,15 @@
  * (default) we cluster all the CPUs that shares a L2 cache, while
  * cluster_cache_index = 3 we cluster all CPs that shares a L3 cache
  */
+#if defined(CONFIG_CEDF_DEFAULT_L1)
+int cluster_index = 1;
+#elif defined(CONFIG_CEDF_DEFAULT_L2)
 int cluster_index = 2;
+#elif defined(CONFIG_CEDF_DEFAULT_L3)
+int cluster_index = 3;
+#elif defined(CONFIG_CEDF_DEFAULT_ALL)
+int cluster_index = 0;
+#endif
 
 /* forward declaration... a funny thing with C ;) */
 struct clusterdomain;