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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-06-27 13:41:37 +0200
committerIngo Molnar <mingo@elte.hu>2008-06-27 14:31:46 +0200
commit83378269a5fad98f562ebc0f09c349575e6cbfe1 (patch)
tree516128bff6cfe915f93b983e3fe96733707ce09c /kernel/sched.c
parent243e0e7b7d3b54749ece2e879ecd7e2a11874443 (diff)
sched: correct wakeup weight calculations
rw_i = {2, 4, 1, 0} s_i = {2/7, 4/7, 1/7, 0} wakeup on cpu0, weight=1 rw'_i = {3, 4, 1, 0} s'_i = {3/8, 4/8, 1/8, 0} s_0 = S * rw_0 / \Sum rw_j -> \Sum rw_j = S*rw_0/s_0 = 1*2*7/2 = 7 (correct) s'_0 = S * (rw_0 + 1) / (\Sum rw_j + 1) = 1 * (2+1) / (7+1) = 3/8 (correct so we find that adding 1 to cpu0 gains 5/56 in weight if say the other cpu were, cpu1, we'd also have to calculate its 4/56 loss Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 62db0891025..01d3e51b711 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -365,6 +365,10 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
#else
static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
+static inline struct task_group *task_group(struct task_struct *p)
+{
+ return NULL;
+}
#endif /* CONFIG_GROUP_SCHED */