--- linux-2.6.0-test7-base/include/linux/sched.h	2003-10-12 22:34:09.000000000 +1000
+++ linux-2.6.0-test7/include/linux/sched.h	2003-10-12 20:46:55.000000000 +1000
@@ -126,6 +126,7 @@ extern unsigned long nr_iowait(void);
 #define SCHED_NORMAL		0
 #define SCHED_FIFO		1
 #define SCHED_RR		2
+#define SCHED_BATCH		3
 
 struct sched_param {
 	int sched_priority;
@@ -294,6 +295,7 @@ struct signal_struct {
 #define MAX_PRIO		(MAX_RT_PRIO + 40)
 
 #define rt_task(p)		((p)->prio < MAX_RT_PRIO)
+#define batch_task(p)		((p)->policy == SCHED_BATCH)
 
 /*
  * Some day this will be a full-fledged user tracking system..
--- linux-2.6.0-test7-base/kernel/sched.c	2003-10-12 22:34:09.000000000 +1000
+++ linux-2.6.0-test7/kernel/sched.c	2003-10-13 16:24:33.000000000 +1000
@@ -153,8 +153,13 @@
 #define LOW_CREDIT(p) \
 	((p)->interactive_credit < -CREDIT_LIMIT)
 
+/*
+ * Batch tasks are preempted by any priority normal tasks and never
+ * preempt other tasks.
+ */
 #define TASK_PREEMPTS_CURR(p, rq) \
-	((p)->prio < (rq)->curr->prio)
+	((((p)->prio < (rq)->curr->prio) && (!batch_task(p))) || \
+		(!batch_task(p) && batch_task((rq)->curr)))
 
 /*
  * BASE_TIMESLICE scales user-nice values [ -20 ... 19 ]
@@ -172,6 +177,13 @@
 
 static inline unsigned int task_timeslice(task_t *p)
 {
+	/*
+	 * Batch tasks get much longer timeslices to optimise cpu throughput.
+	 * Since they yield to any other tasks this is not a problem.
+	 */
+	if (unlikely(batch_task(p)))
+		return BASE_TIMESLICE(p) * 10;
+
 	return BASE_TIMESLICE(p);
 }
 
@@ -202,7 +214,7 @@ struct runqueue {
 			nr_uninterruptible;
 	task_t *curr, *idle;
 	struct mm_struct *prev_mm;
-	prio_array_t *active, *expired, arrays[2];
+	prio_array_t *active, *expired, *batch, arrays[3];
 	int prev_cpu_load[NR_CPUS];
 #ifdef CONFIG_NUMA
 	atomic_t *node_nr_running;
@@ -364,7 +376,7 @@ static int effective_prio(task_t *p)
 	prio = p->static_prio - bonus;
 	if (prio < MAX_RT_PRIO)
 		prio = MAX_RT_PRIO;
-	if (prio > MAX_PRIO-1)
+	if (prio > MAX_PRIO-1 || batch_task(p))
 		prio = MAX_PRIO-1;
 	return prio;
 }
@@ -374,7 +386,11 @@ static int effective_prio(task_t *p)
  */
 static inline void __activate_task(task_t *p, runqueue_t *rq)
 {
-	enqueue_task(p, rq->active);
+	if (unlikely(batch_task(p)))
+		enqueue_task(p, rq->batch);
+	else
+		enqueue_task(p, rq->active);
+
 	nr_running_inc(rq);
 }
 
@@ -692,6 +708,10 @@ void wake_up_forked_process(task_t * p)
 		p->array->nr_active++;
 		nr_running_inc(rq);
 	}
+
+	if (unlikely(batch_task(current) && !batch_task(p)))
+		resched_task(current);
+
 	task_rq_unlock(rq, &flags);
 }
 
@@ -1408,12 +1428,17 @@ void scheduler_tick(int user_ticks, int 
 		p->time_slice = task_timeslice(p);
 		p->first_time_slice = 0;
 
-		if (!rq->expired_timestamp)
+		if (!rq->expired_timestamp && !batch_task(p))
 			rq->expired_timestamp = jiffies;
-		if (!TASK_INTERACTIVE(p) || EXPIRED_STARVING(rq)) {
-			enqueue_task(p, rq->expired);
-		} else
-			enqueue_task(p, rq->active);
+
+		if (unlikely(batch_task(p)))
+			enqueue_task(p, rq->batch);
+		else {
+			if (!TASK_INTERACTIVE(p) || EXPIRED_STARVING(rq))
+				enqueue_task(p, rq->expired);
+			else
+				enqueue_task(p, rq->active);
+		}
 	} else {
 		/*
 		 * Prevent a too long timeslice allowing a task to monopolize
@@ -1534,16 +1559,33 @@ pick_next_task:
 		/*
 		 * Switch the active and expired arrays.
 		 */
-		rq->active = rq->expired;
-		rq->expired = array;
+		if (likely(rq->expired->nr_active)){
+			rq->active = rq->expired;
+			rq->expired = array;
+			rq->expired_timestamp = 0;
+		} else {
+			rq->active = rq->batch;
+			rq->batch = array;
+		}
+
 		array = rq->active;
-		rq->expired_timestamp = 0;
 	}
 
 	idx = sched_find_first_bit(array->bitmap);
 	queue = array->queue + idx;
 	next = list_entry(queue->next, task_t, run_list);
 
+	/*
+	 * If a batch process is on the active array and normal processes
+	 * exist on the expired array move the batch process to the batch
+	 * array.
+	 */
+	if (unlikely(batch_task(next) && rq->expired->nr_active)){
+		dequeue_task(next, array);
+		enqueue_task(next, rq->batch);
+		goto pick_next_task;
+	}
+
 	if (next->activated > 0) {
 		unsigned long long delta = now - next->timestamp;
 
@@ -1865,10 +1907,11 @@ void set_user_nice(task_t *p, long nice)
 		enqueue_task(p, array);
 		/*
 		 * If the task increased its priority or is running and
-		 * lowered its priority, then reschedule its CPU:
+		 * lowered its priority or is batch, then reschedule its CPU:
 		 */
-		if (delta < 0 || (delta > 0 && task_running(rq, p)))
-			resched_task(rq->curr);
+		if (delta < 0 || ((delta > 0 || batch_task(p)) &&
+			task_running(rq, p)))
+				resched_task(rq->curr);
 	}
 out_unlock:
 	task_rq_unlock(rq, &flags);
@@ -2015,8 +2058,8 @@ static int setscheduler(pid_t pid, int p
 	else {
 		retval = -EINVAL;
 		if (policy != SCHED_FIFO && policy != SCHED_RR &&
-				policy != SCHED_NORMAL)
-			goto out_unlock;
+			policy != SCHED_NORMAL && policy !=SCHED_BATCH)
+				goto out_unlock;
 	}
 
 	/*
@@ -2026,8 +2069,9 @@ static int setscheduler(pid_t pid, int p
 	retval = -EINVAL;
 	if (lp.sched_priority < 0 || lp.sched_priority > MAX_USER_RT_PRIO-1)
 		goto out_unlock;
-	if ((policy == SCHED_NORMAL) != (lp.sched_priority == 0))
-		goto out_unlock;
+	if ((policy == SCHED_NORMAL || policy == SCHED_BATCH) !=
+		(lp.sched_priority == 0))
+			goto out_unlock;
 
 	retval = -EPERM;
 	if ((policy == SCHED_FIFO || policy == SCHED_RR) &&
@@ -2048,7 +2092,7 @@ static int setscheduler(pid_t pid, int p
 	p->policy = policy;
 	p->rt_priority = lp.sched_priority;
 	oldprio = p->prio;
-	if (policy != SCHED_NORMAL)
+	if (policy != SCHED_NORMAL && policy != SCHED_BATCH)
 		p->prio = MAX_USER_RT_PRIO-1 - p->rt_priority;
 	else
 		p->prio = p->static_prio;
@@ -2060,9 +2104,9 @@ static int setscheduler(pid_t pid, int p
 		 * this runqueue and our priority is higher than the current's
 		 */
 		if (rq->curr == p) {
-			if (p->prio > oldprio)
+			if (p->prio > oldprio || batch_task(p))
 				resched_task(rq->curr);
-		} else if (p->prio < rq->curr->prio)
+		} else if (TASK_PREEMPTS_CURR(p, rq))
 			resched_task(rq->curr);
 	}
 
@@ -2268,7 +2312,10 @@ asmlinkage long sys_sched_yield(void)
 	 */
 	if (likely(!rt_task(current))) {
 		dequeue_task(current, array);
-		enqueue_task(current, rq->expired);
+		if (unlikely(batch_task(current)))
+			enqueue_task(current, rq->batch);
+		else
+			enqueue_task(current, rq->expired);
 	} else {
 		list_del(&current->run_list);
 		list_add_tail(&current->run_list, array->queue + current->prio);
@@ -2353,6 +2400,7 @@ asmlinkage long sys_sched_get_priority_m
 		ret = MAX_USER_RT_PRIO-1;
 		break;
 	case SCHED_NORMAL:
+	case SCHED_BATCH:
 		ret = 0;
 		break;
 	}
@@ -2376,6 +2424,7 @@ asmlinkage long sys_sched_get_priority_m
 		ret = 1;
 		break;
 	case SCHED_NORMAL:
+	case SCHED_BATCH:
 		ret = 0;
 	}
 	return ret;
@@ -2808,12 +2857,13 @@ void __init sched_init(void)
 		rq = cpu_rq(i);
 		rq->active = rq->arrays;
 		rq->expired = rq->arrays + 1;
+		rq->batch = rq->arrays + 2;
 		spin_lock_init(&rq->lock);
 		INIT_LIST_HEAD(&rq->migration_queue);
 		atomic_set(&rq->nr_iowait, 0);
 		nr_running_init(rq);
 
-		for (j = 0; j < 2; j++) {
+		for (j = 0; j < 3; j++) {
 			array = rq->arrays + j;
 			for (k = 0; k < MAX_PRIO; k++) {
 				INIT_LIST_HEAD(array->queue + k);