--- linux-2.6.1-O21/kernel/sched.c	2004-01-20 21:27:11.000000000 +1100
+++ linux-2.6.1-hto1/kernel/sched.c	2004-01-24 23:20:46.871705035 +1100
@@ -208,6 +208,7 @@ struct runqueue {
 	atomic_t *node_nr_running;
 	int prev_node_load[MAX_NUMNODES];
 #endif
+	unsigned long cpu;
 	task_t *migration_thread;
 	struct list_head migration_queue;
 
@@ -221,6 +222,10 @@ static DEFINE_PER_CPU(struct runqueue, r
 #define task_rq(p)		cpu_rq(task_cpu(p))
 #define cpu_curr(cpu)		(cpu_rq(cpu)->curr)
 
+#define ht_active		(cpu_has_ht && smp_num_siblings > 1)
+#define ht_siblings(cpu1, cpu2)	(ht_active && \
+	cpu_sibling_map[(cpu1)] == (cpu2))
+
 /*
  * Default context-switch locking:
  */
@@ -1159,8 +1164,9 @@ can_migrate_task(task_t *tsk, runqueue_t
 {
 	unsigned long delta = sched_clock() - tsk->timestamp;
 
-	if (!idle && (delta <= JIFFIES_TO_NS(cache_decay_ticks)))
-		return 0;
+	if (!idle && (delta <= JIFFIES_TO_NS(cache_decay_ticks)) &&
+		!ht_siblings(this_cpu, task_cpu(tsk)))
+			return 0;
 	if (task_running(rq, tsk))
 		return 0;
 	if (!cpu_isset(this_cpu, tsk->cpus_allowed))
@@ -1195,15 +1201,23 @@ static void load_balance(runqueue_t *thi
 	imbalance /= 2;
 
 	/*
+	 * For hyperthread siblings take tasks from the active array
+	 * to get cache-warm tasks since they share caches.
+	 */
+	if (ht_siblings(this_cpu, busiest->cpu))
+		array = busiest->active;
+	/*
 	 * We first consider expired tasks. Those will likely not be
 	 * executed in the near future, and they are most likely to
 	 * be cache-cold, thus switching CPUs has the least effect
 	 * on them.
 	 */
-	if (busiest->expired->nr_active)
-		array = busiest->expired;
-	else
-		array = busiest->active;
+	else {
+		if (busiest->expired->nr_active)
+			array = busiest->expired;
+		else
+			array = busiest->active;
+	}
 
 new_array:
 	/* Start searching at priority 0: */
@@ -1214,9 +1228,16 @@ skip_bitmap:
 	else
 		idx = find_next_bit(array->bitmap, MAX_PRIO, idx);
 	if (idx >= MAX_PRIO) {
-		if (array == busiest->expired) {
-			array = busiest->active;
-			goto new_array;
+		if (ht_siblings(this_cpu, busiest->cpu)){
+			if (array == busiest->active) {
+				array = busiest->expired;
+				goto new_array;
+			}
+		} else {
+			if (array == busiest->expired) {
+				array = busiest->active;
+				goto new_array;
+			}
 		}
 		goto out_unlock;
 	}
@@ -1540,6 +1561,20 @@ need_resched:
 		if (!rq->nr_running) {
 			next = rq->idle;
 			rq->expired_timestamp = 0;
+#ifdef CONFIG_SMP
+			if (ht_active) {
+				/*
+				 * If a HT sibling task is sleeping due to
+				 * priority reasons wake it up now
+				 */
+				runqueue_t *htrq;
+				htrq = cpu_rq(cpu_sibling_map[(rq->cpu)]);
+
+				if (htrq->curr == htrq->idle &&
+					htrq->nr_running)
+						resched_task(htrq->idle);
+			}
+#endif
 			goto switch_tasks;
 		}
 	}
@@ -1560,6 +1595,47 @@ need_resched:
 	queue = array->queue + idx;
 	next = list_entry(queue->next, task_t, run_list);
 
+#ifdef CONFIG_SMP
+	if (ht_active && next->mm && !rt_task(next)) {
+		runqueue_t *htrq;
+		htrq = cpu_rq(cpu_sibling_map[(rq->cpu)]);
+		task_t *htcurr;
+		htcurr = htrq->curr;
+
+		if (likely(htcurr->mm && !rt_task(htcurr))){
+			/*
+			 * If a user task with >10 dynamic +
+			 * static priority difference from another
+			 * running user task on the hyperthread sibling
+			 * is trying to schedule, delay it to prevent a
+			 * lower priority task from using an unfair
+			 * proportion of the physical cpu resources.
+			 */
+			if (next->prio + next->static_prio >
+				htcurr->prio + htcurr->static_prio + 10) {
+					next = rq->idle;
+					goto switch_tasks;
+			}
+
+			/*
+			 * Reschedule a lower priority task
+			 * on the HT sibling if present.
+			 */
+			if (htcurr->prio + htcurr->static_prio >
+				next->prio + next->static_prio + 10)
+					resched_task(htcurr);
+			else
+				/*
+				 * If a HT sibling task has been put to sleep
+				 * previously for priority reasons wake it up
+				 * now.
+				 */
+				if (htcurr == htrq->idle && htrq->nr_running)
+					resched_task(htcurr);
+		}
+	}
+#endif
+
 	if (next->activated > 0) {
 		unsigned long long delta = now - next->timestamp;
 
@@ -2814,6 +2890,7 @@ void __init sched_init(void)
 		prio_array_t *array;
 
 		rq = cpu_rq(i);
+		rq->cpu = (unsigned long)(i);
 		rq->active = rq->arrays;
 		rq->expired = rq->arrays + 1;
 		rq->best_expired_prio = MAX_PRIO;