diff -Naurp linux-2.6.4/arch/i386/kernel/smpboot.c linux-2.6.4-ck1/arch/i386/kernel/smpboot.c
--- linux-2.6.4/arch/i386/kernel/smpboot.c	2004-03-11 22:25:06.951671222 +1100
+++ linux-2.6.4-ck1/arch/i386/kernel/smpboot.c	2004-03-11 22:25:48.405213977 +1100
@@ -1159,8 +1159,12 @@ __init void arch_init_sched_domains(void
 		int j;
 		first_cpu = last_cpu = NULL;
 
-		if (i != first_cpu(cpu_domain->span))
+		if (i != first_cpu(cpu_domain->span)) {
+			cpu_sched_domain(i)->flags |= SD_FLAG_SHARE_CPUPOWER;
+			cpu_sched_domain(first_cpu(cpu_domain->span))->flags |=
+				SD_FLAG_SHARE_CPUPOWER;
 			continue;
+		}
 
 		for_each_cpu_mask(j, cpu_domain->span) {
 			struct sched_group *cpu = &sched_group_cpus[j];
@@ -1279,8 +1283,12 @@ __init void arch_init_sched_domains(void
 		int j;
 		first_cpu = last_cpu = NULL;
 
-		if (i != first_cpu(cpu_domain->span))
+		if (i != first_cpu(cpu_domain->span)) {
+			cpu_sched_domain(i)->flags |= SD_FLAG_SHARE_CPUPOWER;
+			cpu_sched_domain(first_cpu(cpu_domain->span))->flags |=
+				SD_FLAG_SHARE_CPUPOWER;
 			continue;
+		}
 
 		for_each_cpu_mask(j, cpu_domain->span) {
 			struct sched_group *cpu = &sched_group_cpus[j];
diff -Naurp linux-2.6.4/include/linux/sched.h linux-2.6.4-ck1/include/linux/sched.h
--- linux-2.6.4/include/linux/sched.h	2004-03-11 22:25:06.956670443 +1100
+++ linux-2.6.4-ck1/include/linux/sched.h	2004-03-11 22:25:48.407213666 +1100
@@ -537,6 +537,7 @@ do { if (atomic_dec_and_test(&(tsk)->usa
 #define SD_FLAG_EXEC		2	/* Balance on exec */
 #define SD_FLAG_WAKE		4	/* Balance on task wakeup */
 #define SD_FLAG_FASTMIGRATE	8	/* Sync wakes put task on waking CPU */
+#define SD_FLAG_SHARE_CPUPOWER	16	/* Domain members share cpu power */
 
 struct sched_group {
 	struct sched_group *next;	/* Must be a circular list */
@@ -562,6 +563,7 @@ struct sched_domain {
 	unsigned int imbalance_pct;	/* No balance until over watermark */
 	unsigned long long cache_hot_time; /* Task considered cache hot (ns) */
 	unsigned int cache_nice_tries;	/* Leave cache hot tasks for # tries */
+	unsigned int per_cpu_gain;	/* CPU % gained by adding domain cpus */
 	int flags;			/* See SD_FLAG_* */
 
 	/* Runtime fields. */
@@ -581,6 +583,7 @@ struct sched_domain {
 	.imbalance_pct		= 110,			\
 	.cache_hot_time		= 0,			\
 	.cache_nice_tries	= 0,			\
+	.per_cpu_gain		= 15,			\
 	.flags			= SD_FLAG_FASTMIGRATE | SD_FLAG_NEWIDLE | SD_FLAG_WAKE,\
 	.last_balance		= jiffies,		\
 	.balance_interval	= 1,			\
@@ -598,6 +601,7 @@ struct sched_domain {
 	.imbalance_pct		= 125,			\
 	.cache_hot_time		= (5*1000000/2),	\
 	.cache_nice_tries	= 1,			\
+	.per_cpu_gain		= 100,			\
 	.flags			= SD_FLAG_FASTMIGRATE | SD_FLAG_NEWIDLE,\
 	.last_balance		= jiffies,		\
 	.balance_interval	= 1,			\
@@ -616,6 +620,7 @@ struct sched_domain {
 	.imbalance_pct		= 125,			\
 	.cache_hot_time		= (10*1000000),		\
 	.cache_nice_tries	= 1,			\
+	.per_cpu_gain		= 100,			\
 	.flags			= SD_FLAG_EXEC,		\
 	.last_balance		= jiffies,		\
 	.balance_interval	= 1,			\
diff -Naurp linux-2.6.4/kernel/sched.c linux-2.6.4-ck1/kernel/sched.c
--- linux-2.6.4/kernel/sched.c	2004-03-11 22:25:06.962669508 +1100
+++ linux-2.6.4-ck1/kernel/sched.c	2004-03-11 22:25:48.411213043 +1100
@@ -207,9 +207,8 @@ struct runqueue {
 	struct mm_struct *prev_mm;
 	prio_array_t *active, *expired, arrays[2];
 	int best_expired_prio;
-
+	int cpu;
 	atomic_t nr_iowait;
-
 #ifdef CONFIG_SMP
 	unsigned long cpu_load[NR_CPUS];
 #endif
@@ -1765,6 +1764,25 @@ static inline void rebalance_tick(int th
 }
 #endif
 
+#ifdef CONFIG_SCHED_SMT
+static inline int wake_priority_sleeper(runqueue_t *rq)
+{	/*
+	 * If an SMT sibling task has been put to sleep for priority
+	 * reasons reschedule the idle task to see if it can now run.
+	 */
+	if (rq->nr_running) {
+		resched_task(rq->idle);
+		return 1;
+	}
+	return 0;
+}
+#else
+static inline int wake_priority_sleeper(runqueue_t *rq)
+{
+	return 0;
+}
+#endif
+
 DEFINE_PER_CPU(struct kernel_stat, kstat);
 
 EXPORT_PER_CPU_SYMBOL(kstat);
@@ -1818,6 +1836,8 @@ void scheduler_tick(int user_ticks, int 
 			cpustat->iowait += sys_ticks;
 		else
 			cpustat->idle += sys_ticks;
+		if (wake_priority_sleeper(rq))
+			goto out;
 		rebalance_tick(cpu, rq, IDLE);
 		return;
 	}
@@ -1905,6 +1925,91 @@ out:
 	rebalance_tick(cpu, rq, NOT_IDLE);
 }
 
+#ifdef CONFIG_SCHED_SMT
+static inline void wake_sleeping_dependent(runqueue_t *rq)
+{
+	int i, this_cpu = rq->cpu;
+	struct sched_domain *sd = cpu_sched_domain(this_cpu);
+	cpumask_t sibling_map;
+
+	if (!(sd->flags & SD_FLAG_SHARE_CPUPOWER)) {
+		/* Not SMT */
+		return;
+	}
+
+	cpus_and(sibling_map, sd->span, cpu_online_map);
+	cpu_clear(this_cpu, sibling_map);
+	for_each_cpu_mask(i, sibling_map) {
+		runqueue_t *smt_rq;
+
+		smt_rq = cpu_rq(i);
+
+		/*
+		 * If an SMT sibling task is sleeping due to priority
+		 * reasons wake it up now.
+		 */
+		if (smt_rq->curr == smt_rq->idle && smt_rq->nr_running)
+			resched_task(smt_rq->idle);
+	}
+}
+
+static inline int dependent_sleeper(runqueue_t *rq, task_t *p)
+{
+	int ret = 0, i, this_cpu = rq->cpu;
+	struct sched_domain *sd = cpu_sched_domain(this_cpu);
+	cpumask_t sibling_map;
+
+	if (!(sd->flags & SD_FLAG_SHARE_CPUPOWER)) {
+		/* Not SMT */
+		return 0;
+	}
+
+	cpus_and(sibling_map, sd->span, cpu_online_map);
+	cpu_clear(this_cpu, sibling_map);
+	for_each_cpu_mask(i, sibling_map) {
+		runqueue_t *smt_rq;
+		task_t *smt_curr;
+
+		smt_rq = cpu_rq(i);
+		smt_curr = smt_rq->curr;
+
+		/*
+		 * If a user task with lower static priority than the
+		 * running task on the SMT sibling is trying to schedule,
+		 * delay it till there is proportionately less timeslice
+		 * left of the sibling task to prevent a lower priority
+		 * task from using an unfair proportion of the
+		 * physical cpu's resources. -ck
+		 */
+		if (((smt_curr->time_slice * (100 - sd->per_cpu_gain) / 100) >
+			task_timeslice(p) || rt_task(smt_curr)) &&
+			p->mm && smt_curr->mm && !rt_task(p))
+				ret |= 1;
+
+		/*
+		 * Reschedule a lower priority task on the SMT sibling,
+		 * or wake it up if it has been put to sleep for priority
+		 * reasons.
+		 */
+		if ((((p->time_slice * (100 - sd->per_cpu_gain) / 100) > 
+			task_timeslice(smt_curr) || rt_task(p)) && 
+			smt_curr->mm && p->mm && !rt_task(smt_curr)) ||
+			(smt_curr == smt_rq->idle && smt_rq->nr_running))
+				resched_task(smt_curr);
+	}
+	return ret;
+}
+#else
+static inline void wake_sleeping_dependent(runqueue_t *rq)
+{
+}
+
+static inline int dependent_sleeper(runqueue_t *rq, task_t *p)
+{
+	return 0;
+}
+#endif
+
 void scheduling_functions_start_here(void) { }
 
 /*
@@ -1976,6 +2081,7 @@ need_resched:
 		if (!rq->nr_running) {
 			next = rq->idle;
 			rq->expired_timestamp = 0;
+			wake_sleeping_dependent(rq);
 			goto switch_tasks;
 		}
 	}
@@ -1996,6 +2102,11 @@ need_resched:
 	queue = array->queue + idx;
 	next = list_entry(queue->next, task_t, run_list);
 
+	if (dependent_sleeper(rq, next)) {
+		next = rq->idle;
+		goto switch_tasks;
+	}
+
 	if (next->activated > 0) {
 		unsigned long long delta = now - next->timestamp;
 
@@ -3417,6 +3528,7 @@ void __init sched_init(void)
 #endif
 
 		rq = cpu_rq(i);
+		rq->cpu = i;
 		rq->active = rq->arrays;
 		rq->expired = rq->arrays + 1;
 		rq->best_expired_prio = MAX_PRIO;