[PATCH] Fix boot-time slowdown for measure_migration_cost

This reduces the amount of time the migration cost calculations cost
during bootup. Based on numbers by Tony Luck <tony.luck@intel.com>.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched.c b/kernel/sched.c
index 3ee2ae45125f711bd52eb8635cf335cc9b15ffe9..ec7fd9cee30665e7626ec7d3fb92f9ee6bd57731 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5141,7 +5141,7 @@ static void init_sched_build_groups(struct sched_group groups[], cpumask_t span,
 #define SEARCH_SCOPE           2
 #define MIN_CACHE_SIZE         (64*1024U)
 #define DEFAULT_CACHE_SIZE     (5*1024*1024U)
-#define ITERATIONS             2
+#define ITERATIONS             1
 #define SIZE_THRESH            130
 #define COST_THRESH            130
 
@@ -5480,9 +5480,9 @@ static unsigned long long measure_migration_cost(int cpu1, int cpu2)
                                break;
                        }
                /*
-                * Increase the cachesize in 5% steps:
+                * Increase the cachesize in 10% steps:
                 */
-               size = size * 20 / 19;
+               size = size * 10 / 9;
        }
 
        if (migration_debug)