[PATCH][NET_SCHED] Update htb rate when stats are polled.

[Ranjit Manomohan]

Currently the HTB rate for a class is update very slowly (once
every 16 seconds). This patch updates the rate whenever the stats
are requested from user space. This enables more accurate rate
monitoring.

Signed-off-by: Ranjit Manomohan <[EMAIL PROTECTED]>

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 035788c..1d6ec60 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -92,6 +92,7 @@ struct htb_class {
        struct gnet_stats_basic bstats;
        struct gnet_stats_queue qstats;
        struct gnet_stats_rate_est rate_est;
+       unsigned long rate_est_when;    /* last time rate was calculated */
        struct tc_htb_xstats xstats;    /* our special stats */
        int refcnt;             /* usage count of this class */

@@ -679,6 +680,23 @@ static int htb_requeue(struct sk_buff *s

 #ifdef HTB_RATECM
 #define RT_GEN(D,R) R+=D-(R/HTB_EWMAC);D=0
+
+/* Update packet/byte rate for a class. */
+static void calc_rate(struct htb_class *cl)
+{
+       unsigned long now = jiffies;
+       if (time_after(now, (cl->rate_est_when + HZ))) {
+       unsigned int elapsed_secs =
+                       (now - cl->rate_est_when)/HZ;
+               cl->sum_bytes /= elapsed_secs;
+               cl->sum_packets /= elapsed_secs;
+               RT_GEN (cl->sum_bytes,cl->rate_bytes);
+               RT_GEN (cl->sum_packets,cl->rate_packets);
+               cl->rate_est_when = now;
+       } else if time_before(now, cl->rate_est_when)
+               cl->rate_est_when = now; /* Wraparound */
+}
+
 static void htb_rate_timer(unsigned long arg)
 {
        struct Qdisc *sch = (struct Qdisc *)arg;
@@ -697,10 +715,8 @@ static void htb_rate_timer(unsigned long
        if (++q->recmp_bucket >= HTB_HSIZE)
                q->recmp_bucket = 0;

-       hlist_for_each_entry(cl,p, q->hash + q->recmp_bucket, hlist) {
-               RT_GEN(cl->sum_bytes, cl->rate_bytes);
-               RT_GEN(cl->sum_packets, cl->rate_packets);
-       }
+       hlist_for_each_entry(cl,p, q->hash + q->recmp_bucket, hlist)
+               calc_rate(cl);
        spin_unlock_bh(&sch->dev->queue_lock);
 }
 #endif
@@ -1176,8 +1192,9 @@ htb_dump_class_stats(struct Qdisc *sch,
        struct htb_class *cl = (struct htb_class *)arg;

 #ifdef HTB_RATECM
-       cl->rate_est.bps = cl->rate_bytes / (HTB_EWMAC * HTB_HSIZE);
-       cl->rate_est.pps = cl->rate_packets / (HTB_EWMAC * HTB_HSIZE);
+       calc_rate(cl);
+       cl->rate_est.bps = cl->rate_bytes / HTB_EWMAC;
+       cl->rate_est.pps = cl->rate_packets / HTB_EWMAC;
 #endif

        if (!cl->level && cl->un.leaf.q)
@@ -1464,6 +1481,7 @@ static int htb_change_class(struct Qdisc
                cl->mbuffer = 60 * PSCHED_TICKS_PER_SEC;     /* 1min */
                cl->t_c = psched_get_time();
                cl->cmode = HTB_CAN_SEND;
+               cl->rate_est_when = jiffies;

                /* attach to the hash list and parent's family */
                hlist_add_head(&cl->hlist, q->hash + htb_hash(classid));
-
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