Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: scheduler interactivity - does this patch help? | From | Felipe Alfaro Solana <> | Date | 09 Jun 2003 21:22:34 +0200 |
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On Mon, 2003-06-09 at 07:43, Martin J. Bligh wrote: > I've had this patch (I think from Ingo) kicking around in -mjb > for a while. I'm going to drop it unless someone thinks it's useful > for some testcase you have ... anyone interested? > > Thanks, > > M. > > diff -urpN -X /home/fletch/.diff.exclude 400-reiserfs_dio/kernel/sched.c 420-sched_interactive/kernel/sched.c > --- 400-reiserfs_dio/kernel/sched.c Fri May 30 19:26:34 2003 > +++ 420-sched_interactive/kernel/sched.c Fri May 30 19:28:06 2003 > @@ -89,6 +89,8 @@ int node_threshold = 125; > #define STARVATION_LIMIT (starvation_limit) > #define NODE_THRESHOLD (node_threshold) > > +#define TIMESLICE_GRANULARITY (HZ/20 ?: 1) > + > /* > * If a task is 'interactive' then we reinsert it in the active > * array after it has expired its current timeslice. (it will not > @@ -1365,6 +1367,27 @@ void scheduler_tick(int user_ticks, int > enqueue_task(p, rq->expired); > } else > enqueue_task(p, rq->active); > + } else { > + /* > + * Prevent a too long timeslice allowing a task to monopolize > + * the CPU. We do this by splitting up the timeslice into > + * smaller pieces. > + * > + * Note: this does not mean the task's timeslices expire or > + * get lost in any way, they just might be preempted by > + * another task of equal priority. (one with higher > + * priority would have preempted this task already.) We > + * requeue this task to the end of the list on this priority > + * level, which is in essence a round-robin of tasks with > + * equal priority. > + */ > + if (!(p->time_slice % TIMESLICE_GRANULARITY) && > + (p->array == rq->active)) { > + dequeue_task(p, rq->active); > + set_tsk_need_resched(p); > + p->prio = effective_prio(p); > + enqueue_task(p, rq->active); > + } > } > out_unlock: > spin_unlock(&rq->lock); >
I'm currently testing it on a modified 2.5.70-mm6 kernel (with HZ set to 1000) and seems to help a little with XMMS's chunky audio playback when X is reniced to -20.
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