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Groups > linux.kernel > #1389927 > unrolled thread
| Started by | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| First post | 2016-04-28 11:20 +0200 |
| Last post | 2016-04-29 06:20 +0200 |
| Articles | 3 — 3 participants |
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Re: [PATCH v3 5/6] sched/fair: Rename scale_load() and scale_load_down() Peter Zijlstra <peterz@infradead.org> - 2016-04-28 11:20 +0200
Re: [PATCH v3 5/6] sched/fair: Rename scale_load() and scale_load_down() Vincent Guittot <vincent.guittot@linaro.org> - 2016-04-28 13:20 +0200
Re: [PATCH v3 5/6] sched/fair: Rename scale_load() and scale_load_down() Yuyang Du <yuyang.du@intel.com> - 2016-04-29 06:20 +0200
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Date | 2016-04-28 11:20 +0200 |
| Subject | Re: [PATCH v3 5/6] sched/fair: Rename scale_load() and scale_load_down() |
| Message-ID | <rsQh3-Jd-11@gated-at.bofh.it> |
On Tue, Apr 05, 2016 at 12:12:30PM +0800, Yuyang Du wrote:
> Rename scale_load() and scale_load_down() to user_to_kernel_load()
> and kernel_to_user_load() respectively, to allow the names to bear
> what they are really about.
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -189,7 +189,7 @@ static void __update_inv_weight(struct load_weight *lw)
> if (likely(lw->inv_weight))
> return;
>
> - w = scale_load_down(lw->weight);
> + w = kernel_to_user_load(lw->weight);
>
> if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST))
> lw->inv_weight = 1;
> @@ -213,7 +213,7 @@ static void __update_inv_weight(struct load_weight *lw)
> */
> static u64 __calc_delta(u64 delta_exec, unsigned long weight, struct load_weight *lw)
> {
> - u64 fact = scale_load_down(weight);
> + u64 fact = kernel_to_user_load(weight);
> int shift = WMULT_SHIFT;
>
> __update_inv_weight(lw);
> @@ -6952,10 +6952,11 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
> */
> if (busiest->group_type == group_overloaded &&
> local->group_type == group_overloaded) {
> + unsigned long min_cpu_load =
> + kernel_to_user_load(NICE_0_LOAD) * busiest->group_capacity;
> load_above_capacity = busiest->sum_nr_running * NICE_0_LOAD;
> - if (load_above_capacity > scale_load(busiest->group_capacity))
> - load_above_capacity -=
> - scale_load(busiest->group_capacity);
> + if (load_above_capacity > min_cpu_load)
> + load_above_capacity -= min_cpu_load;
> else
> load_above_capacity = ~0UL;
> }
Except these 3 really are not about user/kernel visible fixed point
ranges _at_all_... :/
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| From | Vincent Guittot <vincent.guittot@linaro.org> |
|---|---|
| Date | 2016-04-28 13:20 +0200 |
| Message-ID | <rsS9b-28N-13@gated-at.bofh.it> |
| In reply to | #1389927 |
Le Thursday 28 Apr 2016 à 11:19:19 (+0200), Peter Zijlstra a écrit :
> On Tue, Apr 05, 2016 at 12:12:30PM +0800, Yuyang Du wrote:
> > Rename scale_load() and scale_load_down() to user_to_kernel_load()
> > and kernel_to_user_load() respectively, to allow the names to bear
> > what they are really about.
>
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -189,7 +189,7 @@ static void __update_inv_weight(struct load_weight *lw)
> > if (likely(lw->inv_weight))
> > return;
> >
> > - w = scale_load_down(lw->weight);
> > + w = kernel_to_user_load(lw->weight);
> >
> > if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST))
> > lw->inv_weight = 1;
> > @@ -213,7 +213,7 @@ static void __update_inv_weight(struct load_weight *lw)
> > */
> > static u64 __calc_delta(u64 delta_exec, unsigned long weight, struct load_weight *lw)
> > {
> > - u64 fact = scale_load_down(weight);
> > + u64 fact = kernel_to_user_load(weight);
> > int shift = WMULT_SHIFT;
> >
> > __update_inv_weight(lw);
> > @@ -6952,10 +6952,11 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
> > */
> > if (busiest->group_type == group_overloaded &&
> > local->group_type == group_overloaded) {
> > + unsigned long min_cpu_load =
> > + kernel_to_user_load(NICE_0_LOAD) * busiest->group_capacity;
> > load_above_capacity = busiest->sum_nr_running * NICE_0_LOAD;
> > - if (load_above_capacity > scale_load(busiest->group_capacity))
> > - load_above_capacity -=
> > - scale_load(busiest->group_capacity);
> > + if (load_above_capacity > min_cpu_load)
> > + load_above_capacity -= min_cpu_load;
> > else
> > load_above_capacity = ~0UL;
> > }
>
> Except these 3 really are not about user/kernel visible fixed point
> ranges _at_all_... :/
While trying to optimize the calcultaion of min_cpu_load, i have broken evrything
it should be :
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 0b6659d..3411eb7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6953,7 +6953,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
if (busiest->group_type == group_overloaded &&
local->group_type == group_overloaded) {
unsigned long min_cpu_load =
- kernel_to_user_load(NICE_0_LOAD) * busiest->group_capacity;
+ busiest->group_capacity * NICE_0_LOAD / SCHED_CAPACITY_SCALE;
load_above_capacity = busiest->sum_nr_running * NICE_0_LOAD;
if (load_above_capacity > min_cpu_load)
load_above_capacity -= min_cpu_load;
>
>
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| From | Yuyang Du <yuyang.du@intel.com> |
|---|---|
| Date | 2016-04-29 06:20 +0200 |
| Message-ID | <rt84i-86H-9@gated-at.bofh.it> |
| In reply to | #1389927 |
On Thu, Apr 28, 2016 at 11:19:19AM +0200, Peter Zijlstra wrote:
> On Tue, Apr 05, 2016 at 12:12:30PM +0800, Yuyang Du wrote:
> > Rename scale_load() and scale_load_down() to user_to_kernel_load()
> > and kernel_to_user_load() respectively, to allow the names to bear
> > what they are really about.
>
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -189,7 +189,7 @@ static void __update_inv_weight(struct load_weight *lw)
> > if (likely(lw->inv_weight))
> > return;
> >
> > - w = scale_load_down(lw->weight);
> > + w = kernel_to_user_load(lw->weight);
> >
> > if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST))
> > lw->inv_weight = 1;
> > @@ -213,7 +213,7 @@ static void __update_inv_weight(struct load_weight *lw)
> > */
> > static u64 __calc_delta(u64 delta_exec, unsigned long weight, struct load_weight *lw)
> > {
> > - u64 fact = scale_load_down(weight);
> > + u64 fact = kernel_to_user_load(weight);
> > int shift = WMULT_SHIFT;
> >
> > __update_inv_weight(lw);
[snip]
> Except these 3 really are not about user/kernel visible fixed point
> ranges _at_all_... :/
But are the above two falling back to user fixed point precision? And
the reason being that we can't efficiently do this multiply/divide
thing with increased fixed point for kernel load.
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