Stephen Hemminger wrote:
This is a time based rate limiter for use in network testing. When doing
network tests it is often useful to test at reduced bandwidths. The existing
Token Bucket Filter provides rate control, but causes bursty traffic that
can cause different performance than real world. Another alternative is
the PSPacer, but it depends on pause frames which may also cause issues.
The qdisc depends on high resolution timers and clocks, so it will probably
use more CPU than others making it a poor choice for use when doing traffic
shaping for QOS.
Signed-off-by: Stephen Hemminger <[EMAIL PROTECTED]>
--- a/include/linux/pkt_sched.h 2007-10-30 09:18:29.000000000 -0700
+++ b/include/linux/pkt_sched.h 2007-12-07 13:37:50.000000000 -0800
@@ -475,4 +475,10 @@ struct tc_netem_corrupt
#define NETEM_DIST_SCALE 8192
+struct tc_rlim_qopt
+{
+ __u32 limit; /* fifo limit (packets) */
+ __u32 rate; /* bits per sec */
This seems a bit small, 512mbit is the maximum rate.
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ b/net/sched/sch_rlim.c 2007-12-07 16:22:10.000000000 -0800
@@ -0,0 +1,350 @@
+static struct sk_buff *rlim_dequeue(struct Qdisc *sch)
+{
+ struct rlim_sched_data *q = qdisc_priv(sch);
+ struct sk_buff *skb;
+ ktime_t now = ktime_get();
+
+ /* if haven't reached the correct time slot, start timer */
+ if (now.tv64 < q->next_send.tv64) {
+ sch->flags |= TCQ_F_THROTTLED;
+ hrtimer_start(&q->watchdog.timer, q->next_send,
+ HRTIMER_MODE_ABS);
+ return NULL;
+ }
+
+ skb = q->qdisc->dequeue(q->qdisc);
+ if (skb) {
+ q->next_send = ktime_add_ns(now, pkt_time(q, skb));
+ sch->flags &= ~TCQ_F_THROTTLED;
qlen is not decremented here.
+ }
+ return skb;
+}
+
+static int rlim_requeue(struct sk_buff *skb, struct Qdisc *sch)
+{
+ struct rlim_sched_data *q = qdisc_priv(sch);
+ int ret;
+
+ ret = q->qdisc->ops->requeue(skb, q->qdisc);
+ if (!ret) {
+ q->next_send = ktime_sub_ns(q->next_send, pkt_time(q, skb));
+ sch->q.qlen++;
+ sch->qstats.requeues++;
+ }
+
+ return ret;
+}
+
+static void rlim_reset(struct Qdisc *sch)
+{
+ struct rlim_sched_data *q = qdisc_priv(sch);
+
+ qdisc_reset_queue(sch);
This should reset the child.
+
+ q->next_send = ktime_get();
+ qdisc_watchdog_cancel(&q->watchdog);
+}
+
+static int rlim_change(struct Qdisc *sch, struct rtattr *opt)
+{
+ struct rlim_sched_data *q = qdisc_priv(sch);
+ const struct tc_rlim_qopt *qopt;
+ int err;
+
+ if (opt == NULL || RTA_PAYLOAD(opt) < sizeof(struct tc_rlim_qopt))
+ return -EINVAL;
+
+ qopt = RTA_DATA(opt);
Using nested attributes would make sure we don't run into
problems with extensibility.
+ err = set_fifo_limit(q->qdisc, qopt->limit);
+ if (err)
+ return err;
+
+ q->limit = qopt->limit;
+ if (qopt->rate == 0)
+ q->cost = 0; /* unlimited */
+ else {
+ q->cost = (u64)NSEC_PER_SEC << NSEC_SCALE;
+ do_div(q->cost, qopt->rate);
+ }
+
+ pr_debug("rlim_change: rate=%u cost=%llu\n",
+ qopt->rate, q->cost);
+
+ return 0;
+}
+
+static struct Qdisc_class_ops rlim_class_ops = {
This can be const.
+ .graft = rlim_graft,
+ .leaf = rlim_leaf,
+ .get = rlim_get,
+ .put = rlim_put,
+ .change = rlim_change_class,
+ .delete = rlim_delete,
+ .walk = rlim_walk,
+ .tcf_chain = rlim_find_tcf,
+ .dump = rlim_dump_class,
+};
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
