Re: 2.5.66-(bk) == horrible response times for non X11 applications

[Andrew Morton]

Zwane Mwaikambo <[e-mail]> wrote:
>
> This was not reproduceable with 2.4.18-3 nor with 2.5.66 and the 
> following patch applied;
> 
> http://www.kernel.org/pub/linux/kernel/people/akpm/patches/2.5/2.5.66/2.5.66-mm3/broken-out/sched-interactivity-backboost-revert.patch
> 

There have been multiple reports of this patch fixing starvation problems.

We need to either apply it or fix up the problem by other means.

From: Ingo Molnar <[e-mail]>

the patch below fixes George's setiathome problems (as expected).  It
essentially turns off Linus' improvement, but i dont think it can be fixed
sanely.

the problem with setiathome is that it displays something every now and
then - so it gets a backboost from X, and hovers at a relatively high
priority.

 kernel/sched.c |   13 +------------
 1 files changed, 1 insertion(+), 12 deletions(-)

diff -puN kernel/sched.c~sched-interactivity-backboost-revert kernel/sched.c
--- 25/kernel/sched.c~sched-interactivity-backboost-revert	2003-03-28 22:30:08.000000000 -0800
+++ 25-akpm/kernel/sched.c	2003-03-28 22:30:08.000000000 -0800
@@ -379,19 +379,8 @@ static inline int activate_task(task_t *
 		 * boosting tasks that are related to maximum-interactive
 		 * tasks.
 		 */
-		if (sleep_avg > MAX_SLEEP_AVG) {
-			if (!in_interrupt()) {
-				sleep_avg += current->sleep_avg - MAX_SLEEP_AVG;
-				if (sleep_avg > MAX_SLEEP_AVG)
-					sleep_avg = MAX_SLEEP_AVG;
-
-				if (current->sleep_avg != sleep_avg) {
-					current->sleep_avg = sleep_avg;
-					requeue_waker = 1;
-				}
-			}
+		if (sleep_avg > MAX_SLEEP_AVG)
 			sleep_avg = MAX_SLEEP_AVG;
-		}
 		if (p->sleep_avg != sleep_avg) {
 			p->sleep_avg = sleep_avg;
 			p->prio = effective_prio(p);

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