lkml.org 
[lkml]   [2015]   [Mar]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH v10 04/11] sched: Make sched entity usage tracking scale-invariant
On Fri, Feb 27, 2015 at 04:54:07PM +0100, Vincent Guittot wrote:

> + unsigned long scale_freq = arch_scale_freq_capacity(NULL, cpu);

> + sa->running_avg_sum += delta_w * scale_freq
> + >> SCHED_CAPACITY_SHIFT;

so the only thing that could be improved is somehow making this
multiplication go away when the arch doesn't implement the function.

But I'm not sure how to do that without #ifdef.

Maybe a little something like so then... that should make the compiler
get rid of those multiplications unless the arch needs them.


--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2484,8 +2484,6 @@ static u32 __compute_runnable_contrib(u6
return contrib + runnable_avg_yN_sum[n];
}

-unsigned long __weak arch_scale_freq_capacity(struct sched_domain *sd, int cpu);
-
/*
* We can represent the historical contribution to runnable average as the
* coefficients of a geometric series. To do this we sub-divide our runnable
@@ -6015,11 +6013,6 @@ static unsigned long default_scale_capac
return SCHED_CAPACITY_SCALE;
}

-unsigned long __weak arch_scale_freq_capacity(struct sched_domain *sd, int cpu)
-{
- return default_scale_capacity(sd, cpu);
-}
-
static unsigned long default_scale_cpu_capacity(struct sched_domain *sd, int cpu)
{
if ((sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1))
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1387,7 +1387,14 @@ static inline int hrtick_enabled(struct

#ifdef CONFIG_SMP
extern void sched_avg_update(struct rq *rq);
-extern unsigned long arch_scale_freq_capacity(struct sched_domain *sd, int cpu);
+
+#ifndef arch_scale_freq_capacity
+static __always_inline
+unsigned long arch_scale_freq_capacity(struct sched_domain *sd, int cpu)
+{
+ return SCHED_CAPACITY_SCALE;
+}
+#endif

static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
{

\
 
 \ /
  Last update: 2015-03-23 14:41    [W:1.573 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site