Re: [PATCH][2/4] sched: add discrete weighted cpu load function

From: Peter Williams
Date: Mon Mar 13 2006 - 17:36:47 EST


Con Kolivas wrote:
When the type of weighting is known to be zero we can use a simpler
version of source_load with a weighted_cpuload() function. Export that
function to allow relative weighted cpu load to be used by other
subsystems if desired.

Signed-off-by: Con Kolivas <kernel@xxxxxxxxxxx>

---
include/linux/sched.h | 1 +
kernel/sched.c | 10 ++++++++--
2 files changed, 9 insertions(+), 2 deletions(-)

Index: linux-2.6.16-rc6-mm1/include/linux/sched.h
===================================================================
--- linux-2.6.16-rc6-mm1.orig/include/linux/sched.h 2006-03-13 13:25:31.000000000 +1100
+++ linux-2.6.16-rc6-mm1/include/linux/sched.h 2006-03-13 18:29:34.000000000 +1100
@@ -102,6 +102,7 @@ extern int nr_processes(void);
extern unsigned long nr_running(void);
extern unsigned long nr_uninterruptible(void);
extern unsigned long nr_iowait(void);
+extern unsigned long weighted_cpuload(const int cpu);
#include <linux/time.h>
#include <linux/param.h>
Index: linux-2.6.16-rc6-mm1/kernel/sched.c
===================================================================
--- linux-2.6.16-rc6-mm1.orig/kernel/sched.c 2006-03-13 13:25:39.000000000 +1100
+++ linux-2.6.16-rc6-mm1/kernel/sched.c 2006-03-13 17:05:26.000000000 +1100
@@ -914,6 +914,12 @@ inline int task_curr(const task_t *p)
return cpu_curr(task_cpu(p)) == p;
}
+/* Used instead of source_load when we know the type == 0 */
+unsigned long weighted_cpuload(const int cpu)
+{
+ return (cpu_rq(cpu)->raw_weighted_load);
+}
+

Wouldn't this be a candidate for inlining?

#ifdef CONFIG_SMP
typedef struct {
struct list_head list;
@@ -1114,7 +1120,7 @@ find_idlest_cpu(struct sched_group *grou
cpus_and(tmp, group->cpumask, p->cpus_allowed);
for_each_cpu_mask(i, tmp) {
- load = source_load(i, 0);
+ load = weighted_cpuload(i);
if (load < min_load || (load == min_load && i == this_cpu)) {
min_load = load;
@@ -2186,7 +2192,7 @@ static runqueue_t *find_busiest_queue(st
int i;
for_each_cpu_mask(i, group->cpumask) {
- load = source_load(i, 0);
+ load = weighted_cpuload(i);
if (load > max_load) {
max_load = load;
-
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--
Peter Williams pwil3058@xxxxxxxxxxxxxx

"Learning, n. The kind of ignorance distinguishing the studious."
-- Ambrose Bierce
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