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Message-id: <1261142318-26249-1-git-send-email-christian.samsel@rwth-aachen.de>
Date: Fri, 18 Dec 2009 14:18:37 +0100
From: Christian Samsel <christian.samsel@...h-aachen.de>
To: netdev@...r.kernel.org
Cc: Stephen Hemminger <shemminger@...l.org>,
Christian Samsel <christian.samsel@...h-aachen.de>
Subject: [PATCH 1/2] improve netem reorder flexibility
This patch adds a new feature to netem: The newly introduced parameter
reorderdelay TIME is the time a reordered packet is delayed. It can be used in
a combination with delay TIME to enable netem to produce late packets, which is
not possible in the standard netem / iproute2. In the standard version
reordered packets are always sent immediately and therefore are always early packets.
Signed-off-by: Christian Samsel <christian.samsel@...h-aachen.de>
---
include/linux/pkt_sched.h | 21 ++++++++++++---------
net/sched/sch_netem.c | 40 ++++++++++++++++++++++++----------------
2 files changed, 36 insertions(+), 25 deletions(-)
diff --git a/include/linux/pkt_sched.h b/include/linux/pkt_sched.h
index 2cfa4bc..eca6401 100644
--- a/include/linux/pkt_sched.h
+++ b/include/linux/pkt_sched.h
@@ -441,18 +441,21 @@ enum {
#define TCA_NETEM_MAX (__TCA_NETEM_MAX - 1)
struct tc_netem_qopt {
- __u32 latency; /* added delay (us) */
- __u32 limit; /* fifo limit (packets) */
- __u32 loss; /* random packet loss (0=none ~0=100%) */
- __u32 gap; /* re-ordering gap (0 for none) */
- __u32 duplicate; /* random packet dup (0=none ~0=100%) */
- __u32 jitter; /* random jitter in latency (us) */
+ __u32 latency; /* added delay (us) */
+ __u32 limit; /* fifo limit (packets) */
+ __u32 loss; /* random packet loss (0=none ~0=100%) */
+ __u32 gap; /* minimum re-ordering gap (0 for none) */
+ __u32 duplicate; /* random packet dup (0=none ~0=100%) */
+ __u32 jitter; /* random jitter in latency (us) */
+ __u32 reorderdelay; /* delay for reordered packets (us) */
+ __u32 reorderdelayjitter; /* random jitter for reordered packets (us) */
};
struct tc_netem_corr {
- __u32 delay_corr; /* delay correlation */
- __u32 loss_corr; /* packet loss correlation */
- __u32 dup_corr; /* duplicate correlation */
+ __u32 delay_corr; /* delay correlation */
+ __u32 reorderdelay_corr; /* reorderdelay correlation */
+ __u32 loss_corr; /* packet loss correlation */
+ __u32 dup_corr; /* duplicate correlation */
};
struct tc_netem_reorder {
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index d8b10e0..84f7438 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -54,6 +54,7 @@ struct netem_sched_data {
psched_tdiff_t latency;
psched_tdiff_t jitter;
+ psched_tdiff_t reorderdelayjitter;
u32 loss;
u32 limit;
@@ -62,11 +63,12 @@ struct netem_sched_data {
u32 duplicate;
u32 reorder;
u32 corrupt;
+ u32 reorderdelay;
struct crndstate {
u32 last;
u32 rho;
- } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;
+ } delay_cor, reorderdelay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;
struct disttable {
u32 size;
@@ -157,8 +159,10 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
/* We don't fill cb now as skb_unshare() may invalidate it */
struct netem_skb_cb *cb;
struct sk_buff *skb2;
+ struct sk_buff *skb3;
int ret;
int count = 1;
+ psched_tdiff_t delay;
pr_debug("netem_enqueue skb=%p\n", skb);
@@ -213,30 +217,30 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
if (q->gap == 0 || /* not doing reordering */
q->counter < q->gap || /* inside last reordering gap */
q->reorder < get_crandom(&q->reorder_cor)) {
- psched_time_t now;
- psched_tdiff_t delay;
+ /* no reordering (use standard delay) */
delay = tabledist(q->latency, q->jitter,
&q->delay_cor, q->delay_dist);
-
- now = psched_get_time();
- cb->time_to_send = now + delay;
++q->counter;
- ret = qdisc_enqueue(skb, q->qdisc);
} else {
- /*
- * Do re-ordering by putting one out of N packets at the front
- * of the queue.
- */
- cb->time_to_send = psched_get_time();
+ /* Do reordering (use reorderdelay) */
+ delay = tabledist(q->reorderdelay, q->reorderdelayjitter,
+ &q->reorderdelay_cor, q->delay_dist);
q->counter = 0;
+ }
+ cb->time_to_send = psched_get_time()+delay;
- __skb_queue_head(&q->qdisc->q, skb);
- q->qdisc->qstats.backlog += qdisc_pkt_len(skb);
- q->qdisc->qstats.requeues++;
- ret = NET_XMIT_SUCCESS;
+ skb3 = q->qdisc->ops->peek(q->qdisc);
+ if (skb3) {
+ const struct netem_skb_cb *cb2 = netem_skb_cb(skb3);
+
+ /* if new packet is more recent, update watchdog */
+ if (cb->time_to_send < cb2->time_to_send)
+ qdisc_watchdog_schedule(&q->watchdog,cb->time_to_send);
}
+ ret = qdisc_enqueue(skb, q->qdisc);
+
if (likely(ret == NET_XMIT_SUCCESS)) {
sch->q.qlen++;
sch->bstats.bytes += qdisc_pkt_len(skb);
@@ -347,6 +351,7 @@ static void get_correlation(struct Qdisc *sch, const struct nlattr *attr)
const struct tc_netem_corr *c = nla_data(attr);
init_crandom(&q->delay_cor, c->delay_corr);
+ init_crandom(&q->reorderdelay_cor, c->reorderdelay_corr);
init_crandom(&q->loss_cor, c->loss_corr);
init_crandom(&q->dup_cor, c->dup_corr);
}
@@ -418,6 +423,8 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt)
q->counter = 0;
q->loss = qopt->loss;
q->duplicate = qopt->duplicate;
+ q->reorderdelay = qopt->reorderdelay;
+ q->reorderdelayjitter = qopt->reorderdelayjitter;
/* for compatibility with earlier versions.
* if gap is set, need to assume 100% probability
@@ -578,6 +585,7 @@ static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
qopt.loss = q->loss;
qopt.gap = q->gap;
qopt.duplicate = q->duplicate;
+ qopt.reorderdelay = q->reorderdelay;
NLA_PUT(skb, TCA_OPTIONS, sizeof(qopt), &qopt);
cor.delay_corr = q->delay_cor.rho;
--
1.6.4.1
--
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