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SubjectRe: Network slowdown due to CFS
On 03/10/2007, Jarek Poplawski <jarkao2@o2.pl> wrote:
> I can't see anything about clearing. I think, this was about charging,
> which should change the key enough, to move a task to, maybe, a better
> place in a que (tree) than with current ways.

just a quick patch, not tested and I've not evaluated all possible
implications yet.
But someone might give it a try with his/(her -- are even more
welcomed :-) favourite sched_yield() load.

(and white space damaged)

--- sched_fair-old.c 2007-10-03 12:45:17.010306000 +0200
+++ sched_fair.c 2007-10-03 12:44:46.899851000 +0200
@@ -803,7 +803,35 @@ static void yield_task_fair(struct rq *r
update_curr(cfs_rq);

return;
+ } else if (sysctl_sched_compat_yield == 2) {
+ unsigned long ideal_runtime, delta_exec,
+ delta_exec_weighted;
+
+ __update_rq_clock(rq);
+ /*
+ * Update run-time statistics of the 'current'.
+ */
+ update_curr(cfs_rq);
+
+ /*
+ * Emulate (speed up) the effect of us being preempted
+ * by scheduler_tick().
+ */
+ ideal_runtime = sched_slice(cfs_rq, curr);
+ delta_exec = curr->sum_exec_runtime -
curr->prev_sum_exec_runtime;
+
+ if (ideal_runtime > delta_exec) {
+ delta_exec_weighted = ideal_runtime - delta_exec;
+
+ if (unlikely(curr->load.weight != NICE_0_LOAD)) {
+ delta_exec_weighted =
calc_delta_fair(delta_exec_weighted,
+
&se->load);
+ }
+ se->vruntime += delta_exec_weighted;
+ }
+ return;
}
+
/*
* Find the rightmost entry in the rbtree:
*/

>
> Jarek P.
>

--
Best regards,
Dmitry Adamushko
--- sched_fair-old.c 2007-10-03 12:45:17.010306000 +0200
+++ sched_fair.c 2007-10-03 12:44:46.899851000 +0200
@@ -803,7 +803,35 @@ static void yield_task_fair(struct rq *r
update_curr(cfs_rq);

return;
+ } else if (sysctl_sched_compat_yield == 2) {
+ unsigned long ideal_runtime, delta_exec,
+ delta_exec_weighted;
+
+ __update_rq_clock(rq);
+ /*
+ * Update run-time statistics of the 'current'.
+ */
+ update_curr(cfs_rq);
+
+ /*
+ * Emulate the effect of us being preempted
+ * by scheduler_tick().
+ */
+ ideal_runtime = sched_slice(cfs_rq, curr);
+ delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
+
+ if (ideal_runtime > delta_exec) {
+ delta_exec_weighted = ideal_runtime - delta_exec;
+
+ if (unlikely(curr->load.weight != NICE_0_LOAD)) {
+ delta_exec_weighted = calc_delta_fair(delta_exec_weighted,
+ &se->load);
+ }
+ se->vruntime += delta_exec_weighted;
+ }
+ return;
}
+
/*
* Find the rightmost entry in the rbtree:
*/
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