Messages in this thread Patch in this message | | | Date | Sun, 08 Jun 2003 22:43:16 -0700 | From | "Martin J. Bligh" <> | Subject | scheduler interactivity - does this patch help? |
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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); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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