Messages in this thread Patch in this message | | | Date | Fri, 24 Oct 2008 11:06:12 +0200 | From | Peter Zijlstra <> | Subject | [PATCH 1/8] sched: fix a find_busiest_group buglet |
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In one of the group load balancer patches:
commit 408ed066b11cf9ee4536573b4269ee3613bd735e Author: Peter Zijlstra <a.p.zijlstra@chello.nl> Date: Fri Jun 27 13:41:28 2008 +0200 Subject: sched: hierarchical load vs find_busiest_group
The following change:
- if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >= + if (max_load - this_load + 2*busiest_load_per_task >= busiest_load_per_task * imbn) {
made the condition always true, because imbn is [1,2]. Therefore, remove the 2*, and give the it a fair chance.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> --- kernel/sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6/kernel/sched.c =================================================================== --- linux-2.6.orig/kernel/sched.c +++ linux-2.6/kernel/sched.c @@ -3343,7 +3343,7 @@ small_imbalance: } else this_load_per_task = cpu_avg_load_per_task(this_cpu); - if (max_load - this_load + 2*busiest_load_per_task >= + if (max_load - this_load + busiest_load_per_task >= busiest_load_per_task * imbn) { *imbalance = busiest_load_per_task; return busiest; --
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