From 9ee474f55664ff63111c843099d365e7ecffb56f Mon Sep 17 00:00:00 2001 From: Paul Turner Date: Thu, 4 Oct 2012 13:18:30 +0200 Subject: sched: Maintain the load contribution of blocked entities We are currently maintaining: runnable_load(cfs_rq) = \Sum task_load(t) For all running children t of cfs_rq. While this can be naturally updated for tasks in a runnable state (as they are scheduled); this does not account for the load contributed by blocked task entities. This can be solved by introducing a separate accounting for blocked load: blocked_load(cfs_rq) = \Sum runnable(b) * weight(b) Obviously we do not want to iterate over all blocked entities to account for their decay, we instead observe that: runnable_load(t) = \Sum p_i*y^i and that to account for an additional idle period we only need to compute: y*runnable_load(t). This means that we can compute all blocked entities at once by evaluating: blocked_load(cfs_rq)` = y * blocked_load(cfs_rq) Finally we maintain a decay counter so that when a sleeping entity re-awakens we can determine how much of its load should be removed from the blocked sum. Signed-off-by: Paul Turner Reviewed-by: Ben Segall Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20120823141506.585389902@google.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel/sched/core.c') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index fd9d0859350a..00898f1fb69e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1528,7 +1528,6 @@ static void __sched_fork(struct task_struct *p) p->se.avg.runnable_avg_period = 0; p->se.avg.runnable_avg_sum = 0; #endif - #ifdef CONFIG_SCHEDSTATS memset(&p->se.statistics, 0, sizeof(p->se.statistics)); #endif -- cgit v1.2.3