Merge branch 'netem-add-nsec-scheduling-and-slot-feature'

Dave Taht says:

====================
netem: add nsec scheduling and slot feature

This patch series converts netem away from the old "ticks" interface and
userspace API, and adds support for a new "slot" feature intended to
emulate bursty macs such as WiFi and LTE better.

Changes since v2:
Use u64 for packet_len_sched_time()
Use simpler max(time_to_send,q->slot.slot_next)

Changes since v1:
Always pass new nanosecond APIs to userspace
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/uapi/linux/pkt_sched.h

@@ -537,6 +537,9 @@ enum {
 	TCA_NETEM_ECN,
 	TCA_NETEM_RATE64,
 	TCA_NETEM_PAD,
+	TCA_NETEM_LATENCY64,
+	TCA_NETEM_JITTER64,
+	TCA_NETEM_SLOT,
 	__TCA_NETEM_MAX,
 };
 
@@ -574,6 +577,13 @@ struct tc_netem_rate {
 	__s32	cell_overhead;
 };
 
+struct tc_netem_slot {
+	__s64   min_delay; /* nsec */
+	__s64   max_delay;
+	__s32   max_packets;
+	__s32   max_bytes;
+};
+
 enum {
 	NETEM_LOSS_UNSPEC,
 	NETEM_LOSS_GI,		/* General Intuitive - 4 state model */

net/sched/sch_netem.c

@@ -77,8 +77,8 @@ struct netem_sched_data {
 
 	struct qdisc_watchdog watchdog;
 
-	psched_tdiff_t latency;
-	psched_tdiff_t jitter;
+	s64 latency;
+	s64 jitter;
 
 	u32 loss;
 	u32 ecn;
@@ -135,6 +135,13 @@ struct netem_sched_data {
 		u32 a5; /* p23 used only in 4-states */
 	} clg;
 
+	struct tc_netem_slot slot_config;
+	struct slotstate {
+		u64 slot_next;
+		s32 packets_left;
+		s32 bytes_left;
+	} slot;
+
 };
 
 /* Time stamp put into socket buffer control block
@@ -145,7 +152,7 @@ struct netem_sched_data {
  * we save skb->tstamp value in skb->cb[] before destroying it.
  */
 struct netem_skb_cb {
-	psched_time_t	time_to_send;
+	u64	        time_to_send;
 };
 
 static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
@@ -305,11 +312,11 @@ static bool loss_event(struct netem_sched_data *q)
  * std deviation sigma.  Uses table lookup to approximate the desired
  * distribution, and a uniformly-distributed pseudo-random source.
  */
-static psched_tdiff_t tabledist(psched_tdiff_t mu, psched_tdiff_t sigma,
-				struct crndstate *state,
-				const struct disttable *dist)
+static s64 tabledist(s64 mu, s64 sigma,
+		     struct crndstate *state,
+			 const struct disttable *dist)
 {
-	psched_tdiff_t x;
+	s64 x;
 	long t;
 	u32 rnd;
 
@@ -332,10 +339,10 @@ static psched_tdiff_t tabledist(psched_tdiff_t mu, psched_tdiff_t sigma,
 	return  x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu;
 }
 
-static psched_time_t packet_len_2_sched_time(unsigned int len, struct netem_sched_data *q)
+static u64 packet_len_2_sched_time(unsigned int len,
+				   struct netem_sched_data *q)
 {
-	u64 ticks;
-
+	u64 offset;
 	len += q->packet_overhead;
 
 	if (q->cell_size) {
@@ -345,11 +352,9 @@ static psched_time_t packet_len_2_sched_time(unsigned int len, struct netem_sche
 			cells++;
 		len = cells * (q->cell_size + q->cell_overhead);
 	}
-
-	ticks = (u64)len * NSEC_PER_SEC;
-
-	do_div(ticks, q->rate);
-	return PSCHED_NS2TICKS(ticks);
+	offset = (u64)len * NSEC_PER_SEC;
+	do_div(offset, q->rate);
+	return offset;
 }
 
 static void tfifo_reset(struct Qdisc *sch)
@@ -369,7 +374,7 @@ static void tfifo_reset(struct Qdisc *sch)
 static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
 {
 	struct netem_sched_data *q = qdisc_priv(sch);
-	psched_time_t tnext = netem_skb_cb(nskb)->time_to_send;
+	u64 tnext = netem_skb_cb(nskb)->time_to_send;
 	struct rb_node **p = &q->t_root.rb_node, *parent = NULL;
 
 	while (*p) {
@@ -515,13 +520,13 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 	if (q->gap == 0 ||		/* not doing reordering */
 	    q->counter < q->gap - 1 ||	/* inside last reordering gap */
 	    q->reorder < get_crandom(&q->reorder_cor)) {
-		psched_time_t now;
-		psched_tdiff_t delay;
+		u64 now;
+		s64 delay;
 
 		delay = tabledist(q->latency, q->jitter,
 				  &q->delay_cor, q->delay_dist);
 
-		now = psched_get_time();
+		now = ktime_get_ns();
 
 		if (q->rate) {
 			struct netem_skb_cb *last = NULL;
@@ -547,7 +552,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 				 * from delay.
 				 */
 				delay -= last->time_to_send - now;
-				delay = max_t(psched_tdiff_t, 0, delay);
+				delay = max_t(s64, 0, delay);
 				now = last->time_to_send;
 			}
 
@@ -562,7 +567,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 		 * Do re-ordering by putting one out of N packets at the front
 		 * of the queue.
 		 */
-		cb->time_to_send = psched_get_time();
+		cb->time_to_send = ktime_get_ns();
 		q->counter = 0;
 
 		netem_enqueue_skb_head(&sch->q, skb);
@@ -593,6 +598,20 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 	return NET_XMIT_SUCCESS;
 }
 
+/* Delay the next round with a new future slot with a
+ * correct number of bytes and packets.
+ */
+
+static void get_slot_next(struct netem_sched_data *q, u64 now)
+{
+	q->slot.slot_next = now + q->slot_config.min_delay +
+		(prandom_u32() *
+			(q->slot_config.max_delay -
+				q->slot_config.min_delay) >> 32);
+	q->slot.packets_left = q->slot_config.max_packets;
+	q->slot.bytes_left = q->slot_config.max_bytes;
+}
+
 static struct sk_buff *netem_dequeue(struct Qdisc *sch)
 {
 	struct netem_sched_data *q = qdisc_priv(sch);
@@ -609,15 +628,18 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
 	}
 	p = rb_first(&q->t_root);
 	if (p) {
-		psched_time_t time_to_send;
+		u64 time_to_send;
+		u64 now = ktime_get_ns();
 
 		skb = rb_to_skb(p);
 
 		/* if more time remaining? */
 		time_to_send = netem_skb_cb(skb)->time_to_send;
-		if (time_to_send <= psched_get_time()) {
-			rb_erase(p, &q->t_root);
+		if (q->slot.slot_next && q->slot.slot_next < time_to_send)
+			get_slot_next(q, now);
 
+		if (time_to_send <= now &&  q->slot.slot_next <= now) {
+			rb_erase(p, &q->t_root);
 			sch->q.qlen--;
 			qdisc_qstats_backlog_dec(sch, skb);
 			skb->next = NULL;
@@ -636,6 +658,14 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
 				skb->tstamp = 0;
 #endif
 
+			if (q->slot.slot_next) {
+				q->slot.packets_left--;
+				q->slot.bytes_left -= qdisc_pkt_len(skb);
+				if (q->slot.packets_left <= 0 ||
+				    q->slot.bytes_left <= 0)
+					get_slot_next(q, now);
+			}
+
 			if (q->qdisc) {
 				unsigned int pkt_len = qdisc_pkt_len(skb);
 				struct sk_buff *to_free = NULL;
@@ -659,7 +689,10 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
 			if (skb)
 				goto deliver;
 		}
-		qdisc_watchdog_schedule(&q->watchdog, time_to_send);
+
+		qdisc_watchdog_schedule_ns(&q->watchdog,
+					   max(time_to_send,
+					       q->slot.slot_next));
 	}
 
 	if (q->qdisc) {
@@ -690,6 +723,7 @@ static void dist_free(struct disttable *d)
  * Distribution data is a variable size payload containing
  * signed 16 bit values.
  */
+
 static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr)
 {
 	struct netem_sched_data *q = qdisc_priv(sch);
@@ -720,6 +754,23 @@ static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr)
 	return 0;
 }
 
+static void get_slot(struct netem_sched_data *q, const struct nlattr *attr)
+{
+	const struct tc_netem_slot *c = nla_data(attr);
+
+	q->slot_config = *c;
+	if (q->slot_config.max_packets == 0)
+		q->slot_config.max_packets = INT_MAX;
+	if (q->slot_config.max_bytes == 0)
+		q->slot_config.max_bytes = INT_MAX;
+	q->slot.packets_left = q->slot_config.max_packets;
+	q->slot.bytes_left = q->slot_config.max_bytes;
+	if (q->slot_config.min_delay | q->slot_config.max_delay)
+		q->slot.slot_next = ktime_get_ns();
+	else
+		q->slot.slot_next = 0;
+}
+
 static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr)
 {
 	const struct tc_netem_corr *c = nla_data(attr);
@@ -821,6 +872,9 @@ static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
 	[TCA_NETEM_LOSS]	= { .type = NLA_NESTED },
 	[TCA_NETEM_ECN]		= { .type = NLA_U32 },
 	[TCA_NETEM_RATE64]	= { .type = NLA_U64 },
+	[TCA_NETEM_LATENCY64]	= { .type = NLA_S64 },
+	[TCA_NETEM_JITTER64]	= { .type = NLA_S64 },
+	[TCA_NETEM_SLOT]	= { .len = sizeof(struct tc_netem_slot) },
 };
 
 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
@@ -888,8 +942,8 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt)
 
 	sch->limit = qopt->limit;
 
-	q->latency = qopt->latency;
-	q->jitter = qopt->jitter;
+	q->latency = PSCHED_TICKS2NS(qopt->latency);
+	q->jitter = PSCHED_TICKS2NS(qopt->jitter);
 	q->limit = qopt->limit;
 	q->gap = qopt->gap;
 	q->counter = 0;
@@ -918,9 +972,18 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt)
 		q->rate = max_t(u64, q->rate,
 				nla_get_u64(tb[TCA_NETEM_RATE64]));
 
+	if (tb[TCA_NETEM_LATENCY64])
+		q->latency = nla_get_s64(tb[TCA_NETEM_LATENCY64]);
+
+	if (tb[TCA_NETEM_JITTER64])
+		q->jitter = nla_get_s64(tb[TCA_NETEM_JITTER64]);
+
 	if (tb[TCA_NETEM_ECN])
 		q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]);
 
+	if (tb[TCA_NETEM_SLOT])
+		get_slot(q, tb[TCA_NETEM_SLOT]);
+
 	return ret;
 }
 
@@ -1010,9 +1073,12 @@ static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
 	struct tc_netem_reorder reorder;
 	struct tc_netem_corrupt corrupt;
 	struct tc_netem_rate rate;
+	struct tc_netem_slot slot;
 
-	qopt.latency = q->latency;
-	qopt.jitter = q->jitter;
+	qopt.latency = min_t(psched_tdiff_t, PSCHED_NS2TICKS(q->latency),
+			     UINT_MAX);
+	qopt.jitter = min_t(psched_tdiff_t, PSCHED_NS2TICKS(q->jitter),
+			    UINT_MAX);
 	qopt.limit = q->limit;
 	qopt.loss = q->loss;
 	qopt.gap = q->gap;
@@ -1020,6 +1086,12 @@ static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
 	if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt))
 		goto nla_put_failure;
 
+	if (nla_put(skb, TCA_NETEM_LATENCY64, sizeof(q->latency), &q->latency))
+		goto nla_put_failure;
+
+	if (nla_put(skb, TCA_NETEM_JITTER64, sizeof(q->jitter), &q->jitter))
+		goto nla_put_failure;
+
 	cor.delay_corr = q->delay_cor.rho;
 	cor.loss_corr = q->loss_cor.rho;
 	cor.dup_corr = q->dup_cor.rho;
@@ -1056,6 +1128,16 @@ static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
 	if (dump_loss_model(q, skb) != 0)
 		goto nla_put_failure;
 
+	if (q->slot_config.min_delay | q->slot_config.max_delay) {
+		slot = q->slot_config;
+		if (slot.max_packets == INT_MAX)
+			slot.max_packets = 0;
+		if (slot.max_bytes == INT_MAX)
+			slot.max_bytes = 0;
+		if (nla_put(skb, TCA_NETEM_SLOT, sizeof(slot), &slot))
+			goto nla_put_failure;
+	}
+
 	return nla_nest_end(skb, nla);
 
 nla_put_failure: