Revert commit d7102e95b7b9c00277562c29aad421d2d521c5f6,
which causes more than 10% performance regression with aim7.
Signed-off-by: Ken Chen <[email protected]>
--- linux-2.6.16-rc2/include/linux/sched.h.orig 2006-02-13 18:15:09.660276655 -0800
+++ linux-2.6.16-rc2/include/linux/sched.h 2006-02-13 18:15:36.234495079 -0800
@@ -697,12 +697,9 @@ struct task_struct {
int lock_depth; /* BKL lock depth */
-#if defined(CONFIG_SMP)
- int last_waker_cpu; /* CPU that last woke this task up */
-#if defined(__ARCH_WANT_UNLOCKED_CTXSW)
+#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
int oncpu;
#endif
-#endif
int prio, static_prio;
struct list_head run_list;
prio_array_t *array;
--- linux-2.6.16-rc2/kernel/sched.c.orig 2006-02-13 18:11:28.946412171 -0800
+++ linux-2.6.16-rc2/kernel/sched.c 2006-02-13 18:14:29.595824020 -0800
@@ -1294,9 +1294,6 @@ static int try_to_wake_up(task_t *p, uns
}
}
- if (p->last_waker_cpu != this_cpu)
- goto out_set_cpu;
-
if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed)))
goto out_set_cpu;
@@ -1367,8 +1364,6 @@ out_set_cpu:
cpu = task_cpu(p);
}
- p->last_waker_cpu = this_cpu;
-
out_activate:
#endif /* CONFIG_SMP */
if (old_state == TASK_UNINTERRUPTIBLE) {
@@ -1450,12 +1445,9 @@ void fastcall sched_fork(task_t *p, int
#ifdef CONFIG_SCHEDSTATS
memset(&p->sched_info, 0, sizeof(p->sched_info));
#endif
-#if defined(CONFIG_SMP)
- p->last_waker_cpu = cpu;
-#if defined(__ARCH_WANT_UNLOCKED_CTXSW)
+#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
p->oncpu = 0;
#endif
-#endif
#ifdef CONFIG_PREEMPT
/* Want to start with kernel preemption disabled. */
task_thread_info(p)->preempt_count = 1;
Chen, Kenneth W wrote:
> Revert commit d7102e95b7b9c00277562c29aad421d2d521c5f6,
> which causes more than 10% performance regression with aim7.
>
Just to be sure, what kernel did you test with? In particular,
did it have the smpnice patch reverted (as -rc3 does).
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
Index: MM-2.6.X/kernel/sched.c
===================================================================
--- MM-2.6.X.orig/kernel/sched.c 2006-02-16 12:39:30.000000000 +1100
+++ MM-2.6.X/kernel/sched.c 2006-02-16 14:36:24.000000000 +1100
@@ -1061,6 +1061,18 @@ static inline unsigned long target_load(
}
/*
+ * Return the average load per task on the cpu's run queue
+ */
+static inline unsigned long cpu_avg_load_per_task(int cpu)
+{
+ runqueue_t *rq = cpu_rq(cpu);
+ unsigned long n = rq->nr_running;
+ unsigned long load = weighted_load(rq->prio_bias);
+
+ return n ? load / n : load;
+}
+
+/*
* find_idlest_group finds and returns the least busy CPU group within the
* domain.
*/
@@ -1309,6 +1321,7 @@ static int try_to_wake_up(task_t *p, uns
if (this_sd->flags & SD_WAKE_AFFINE) {
unsigned long tl = this_load;
+ unsigned long tl_per_task = cpu_avg_load_per_task(this_cpu);
/*
* If sync wakeup then subtract the (maximum possible)
* effect of the currently running task from the load
@@ -1318,8 +1331,8 @@ static int try_to_wake_up(task_t *p, uns
tl -= weighted_load(p->bias_prio);
if ((tl <= load &&
- tl + target_load(cpu, idx) <= SCHED_LOAD_SCALE) ||
- 100*(tl + SCHED_LOAD_SCALE) <= imbalance*load) {
+ tl + target_load(cpu, idx) <= tl_per_task) ||
+ 100*(tl + tl_per_task) <= imbalance*load) {
/*
* This domain has SD_WAKE_AFFINE and
* p is cache cold in this domain, and