本帖最后由 lin_wang 于 2010-03-19 21:32 编辑
回复 4# emmoblin
那请教下, 用 tc change 频繁更改(2秒一次) htb 的子类时 dmesg 里报 htb: too many events! 是怎么回事呢? 有什么影响?
我看了htb的源码, 那段不是很明白 /**
* htb_do_events - make mode changes to classes at the level
*
* Scans event queue for pending events and applies them. Returns time of
* next pending event (0 for no event in pq, q->now for too many events).
* Note: Applied are events whose have cl->pq_key <= q->now.
*/
static psched_time_t htb_do_events(struct htb_sched *q, int level,
unsigned long start)
{
/* don't run for longer than 2 jiffies; 2 is used instead of
1 to simplify things when jiffy is going to be incremented
too soon */
unsigned long stop_at = start + 2;
while (time_before(jiffies, stop_at)) {
struct htb_class *cl;
long diff;
struct rb_node *p = rb_first(&q->wait_pq[level]);
if (!p)
return 0;
cl = rb_entry(p, struct htb_class, pq_node);
if (cl->pq_key > q->now)
return cl->pq_key;
htb_safe_rb_erase(p, q->wait_pq + level);
diff = psched_tdiff_bounded(q->now, cl->t_c, cl->mbuffer);
htb_change_class_mode(q, cl, &diff);
if (cl->cmode != HTB_CAN_SEND)
htb_add_to_wait_tree(q, cl, diff);
}
/* too much load - let's continue after a break for scheduling */
if (!(q->warned & HTB_WARN_TOOMANYEVENTS)) {
printk(KERN_WARNING "htb: too many events!\n");
q->warned |= HTB_WARN_TOOMANYEVENTS;
}
return q->now;
}
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