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author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2008-04-19 19:45:00 +0200 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-04-19 19:45:00 +0200 |
commit | 8f1bc385cfbab474db6c27b5af1e439614f3025c (patch) | |
tree | e4cfb8255d62621d17bc08ee5f94f42a0cc22677 /kernel/sched.c | |
parent | sched: fair-group: de-couple load-balancing from the rb-trees (diff) | |
download | linux-8f1bc385cfbab474db6c27b5af1e439614f3025c.tar.xz linux-8f1bc385cfbab474db6c27b5af1e439614f3025c.zip |
sched: fair: weight calculations
In order to level the hierarchy, we need to calculate load based on the
root view. That is, each task's load is in the same unit.
A
/ \
B 1
/ \
2 3
To compute 1's load we do:
weight(1)
--------------
rq_weight(A)
To compute 2's load we do:
weight(2) weight(B)
------------ * -----------
rq_weight(B) rw_weight(A)
This yields load fractions in comparable units.
The consequence is that it changes virtual time. We used to have:
time_{i}
vtime_{i} = ------------
weight_{i}
vtime = \Sum vtime_{i} = time / rq_weight.
But with the new way of load calculation we get that vtime equals time.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r-- | kernel/sched.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 3202462109f5..6d55dfc56cab 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1320,6 +1320,9 @@ static void __resched_task(struct task_struct *p, int tif_bit) */ #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) +/* + * delta *= weight / lw + */ static unsigned long calc_delta_mine(unsigned long delta_exec, unsigned long weight, struct load_weight *lw) @@ -1342,12 +1345,6 @@ calc_delta_mine(unsigned long delta_exec, unsigned long weight, return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); } -static inline unsigned long -calc_delta_fair(unsigned long delta_exec, struct load_weight *lw) -{ - return calc_delta_mine(delta_exec, NICE_0_LOAD, lw); -} - static inline void update_load_add(struct load_weight *lw, unsigned long inc) { lw->weight += inc; |