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Subject[PATCH] sched: sched_best_cpu
From
Date
Hi,


Next patch slightly favors the local node when looking for the least
loaded cpu; when the task would not stay on our node we add 1 to the
load to simulate the influence the migration would have on the load.


Frank


--- sched.c.orig 2003-08-09 06:39:35.000000000 +0200
+++ sched.c 2003-08-21 11:45:04.000000000 +0200
@@ -776,29 +776,30 @@
*/
static int sched_best_cpu(struct task_struct *p)
{
- int i, minload, load, best_cpu, node = 0;
+ int i, minload, load, best_cpu, node, pnode;
unsigned long cpumask;

best_cpu = task_cpu(p);
if (cpu_rq(best_cpu)->nr_running <= 2)
return best_cpu;

- minload = 10000000;
+ minload = INT_MAX;
+ node = pnode = cpu_to_node(best_cpu);
for_each_node_with_cpus(i) {
/*
* Node load is always divided by nr_cpus_node to normalise
* load values in case cpu count differs from node to node.
- * We first multiply node_nr_running by 10 to get a little
- * better resolution.
+ * If the node != our node we add the load of the task.
+ * We multiply by NR_CPUS for better resolution.
*/
- load = 10 * atomic_read(&node_nr_running[i]) / nr_cpus_node(i);
+ load = NR_CPUS * (atomic_read(&node_nr_running[i]) + (i != pnode)) / nr_cpus_node(i);
if (load < minload) {
minload = load;
node = i;
}
}

- minload = 10000000;
+ minload = INT_MAX;
cpumask = node_to_cpumask(node);
for (i = 0; i < NR_CPUS; ++i) {
if (!(cpumask & (1UL << i)))
-
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