diff -urN oldtree/Documentation/sysctl/kernel.txt newtree/Documentation/sysctl/kernel.txt
--- oldtree/Documentation/sysctl/kernel.txt	2006-09-24 17:58:58.000000000 -0400
+++ newtree/Documentation/sysctl/kernel.txt	2006-09-24 18:05:38.000000000 -0400
@@ -18,6 +18,7 @@
 show up in /proc/sys/kernel:
 - acpi_video_flags
 - acct
+- compute
 - core_pattern
 - core_uses_pid
 - ctrl-alt-del
@@ -84,6 +85,16 @@
 
 ==============================================================
 
+compute: (Staircase only)
+
+This flag controls the long timeslice, delayed preemption mode in the
+cpu scheduler suitable for scientific computation applications. It
+leads to large latencies so is unsuitable for normal usage.
+
+Disabled by default.
+
+==============================================================
+
 core_pattern:
 
 core_pattern is used to specify a core dumpfile pattern name.
diff -urN oldtree/include/linux/sched.h newtree/include/linux/sched.h
--- oldtree/include/linux/sched.h	2006-09-24 17:58:58.000000000 -0400
+++ newtree/include/linux/sched.h	2006-09-24 17:59:37.000000000 -0400
@@ -208,7 +208,7 @@
 void io_schedule(void);
 long io_schedule_timeout(long timeout);
 #ifdef CONFIG_STAIRCASE
-extern int sched_interactive;
+extern int sched_interactive, sched_compute;
 #endif
 
 extern void cpu_init (void);
diff -urN oldtree/include/linux/sysctl.h newtree/include/linux/sysctl.h
--- oldtree/include/linux/sysctl.h	2006-09-24 17:58:58.000000000 -0400
+++ newtree/include/linux/sysctl.h	2006-09-24 18:00:15.000000000 -0400
@@ -153,7 +153,8 @@
 	KERN_MAX_LOCK_DEPTH=74,
 	KERN_NMI_WATCHDOG=75, /* int: enable/disable nmi watchdog */
 	KERN_PANIC_ON_NMI=76, /* int: whether we will panic on an unrecovered */
-        KERN_INTERACTIVE=77,	/* interactive tasks can have cpu bursts */
+	KERN_INTERACTIVE=77,	/* interactive tasks can have cpu bursts */
+	KERN_COMPUTE=78,	/* adjust timeslices for a compute server */
 };
 
 
diff -urN oldtree/kernel/sched_staircase.c newtree/kernel/sched_staircase.c
--- oldtree/kernel/sched_staircase.c	2006-09-24 17:58:58.000000000 -0400
+++ newtree/kernel/sched_staircase.c	2006-09-24 18:04:38.000000000 -0400
@@ -51,8 +51,17 @@
 /*
  * sched_interactive - sysctl which allows interactive tasks to have bonus
  * raise its priority.
+ * sched_compute - sysctl which enables long timeslices and delayed preemption
+ * for compute server usage.
  */
 int sched_interactive __read_mostly = 1;
+int sched_compute __read_mostly;
+
+/*
+ * CACHE_DELAY is the time preemption is delayed in sched_compute mode
+ * and is set to a nominal 10ms.
+ */
+#define CACHE_DELAY    (10 * (HZ) / 1001 + 1)
 
 /*
  * Convert user-nice values [ -20 ... 0 ... 19 ]
@@ -84,9 +93,10 @@
 
 /*
  * This is the time all tasks within the same priority round robin.
- * Set to a minimum of 6ms.
+ * Set to a minimum of 6ms. It is 10 times longer in compute mode.
  */
-#define RR_INTERVAL		((6 * HZ / 1001) + 1)
+#define _RR_INTERVAL            ((6 * HZ / 1001) + 1)
+#define RR_INTERVAL             (_RR_INTERVAL * (1 + 9 * sched_compute))
 #define DEF_TIMESLICE		(RR_INTERVAL * 19)
 
 
@@ -124,6 +134,7 @@
 	unsigned long nr_uninterruptible;
 
 	unsigned long long timestamp_last_tick;
+        unsigned short cache_ticks, preempted;
 	struct task_struct *curr, *idle;
 	struct mm_struct *prev_mm;
 	unsigned long bitmap[BITS_TO_LONGS(MAX_PRIO + 1)];
@@ -861,7 +872,7 @@
 
 	best_bonus = bonus(p);
 	prio = MAX_RT_PRIO + best_bonus;
-	if (sched_interactive && !batch_task(p))
+	if (sched_interactive && !sched_compute && !batch_task(p))
 		prio -= p->bonus;
 
 	rr = rr_interval(p);
@@ -1324,14 +1335,22 @@
 #endif
 
 /*
- * Check to see if p preempts rq->curr and resched if it does.
+ * Check to see if p preempts rq->curr and resched if it does. In compute
+ * mode we do not preempt for at least CACHE_DELAY and set rq->preempted.
  */
-static inline void preempt(const struct task_struct *p, struct rq *rq)
+static void fastcall preempt(const struct task_struct *p, struct rq *rq)
 {
-	if (TASK_PREEMPTS_CURR(p, rq))
-		resched_task(rq->curr);
-}
+        struct task_struct *curr = rq->curr;
 
+        if (p->prio >= curr->prio)
+                return;
+        if (!sched_compute || rq->cache_ticks >= CACHE_DELAY || !p->mm ||
+            rt_task(p) || curr == rq->idle) {
+                resched_task(curr);
+                return;
+        }
+        rq->preempted = 1;
+}
 
 /***
  * try_to_wake_up - wake up a thread
@@ -2930,6 +2949,9 @@
 		time_slice_expired(p, rq);
 		goto out_unlock;
 	}
+        rq->cache_ticks++;
+        if (rq->preempted && rq->cache_ticks >= CACHE_DELAY)
+                set_tsk_need_resched(p);
 out_unlock:
 	spin_unlock(&rq->lock);
 out:
@@ -3199,6 +3221,7 @@
 
 	sched_info_switch(prev, next);
 	if (likely(prev != next)) {
+                rq->preempted = rq->cache_ticks = 0;
 		next->timestamp = now;
 		rq->nr_switches++;
 		rq->curr = next;
@@ -6634,7 +6657,7 @@
 		rq = cpu_rq(i);
 		spin_lock_init(&rq->lock);
 		lockdep_set_class(&rq->lock, &rq->rq_lock_key);
-		rq->nr_running = 0;
+		rq->nr_running = rq->cache_ticks = rq->preempted = 0;
 
 #ifdef CONFIG_SMP
 		rq->sd = NULL;
diff -urN oldtree/kernel/sysctl.c newtree/kernel/sysctl.c
--- oldtree/kernel/sysctl.c	2006-09-24 17:58:58.000000000 -0400
+++ newtree/kernel/sysctl.c	2006-09-24 18:05:02.000000000 -0400
@@ -696,6 +696,14 @@
                 .mode           = 0644,
                 .proc_handler   = &proc_dointvec,
         },
+        {
+                .ctl_name       = KERN_COMPUTE,
+                .procname       = "compute",
+                .data           = &sched_compute,
+                .maxlen         = sizeof (int),
+                .mode           = 0644,
+                .proc_handler   = &proc_dointvec,
+        },
 #endif
 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
 	{