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net/sched: netem: add per-impairment extended statistics

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Add 64-bit counters for each impairment netem applies (delay, loss,
ECN marking, corruption, duplication, reordering) and for skb
allocation failures during enqueue. Exposed through TCA_STATS_APP
as struct tc_netem_xstats.

Counters increment when an impairment is occurs, independent of later
events that may mask its on-wire effect. Added allocation_errors
(similar to sch_fq) to account for when impairment could not be
applied due to memory pressure, etc.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Link: https://patch.msgid.link/20260509171123.307549-6-stephen@networkplumber.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Stephen Hemminger
2026-05-09 10:03:26 -07:00
committed by Paolo Abeni
parent e8be7cdedc
commit a2f6ed7b48
2 changed files with 59 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/uapi/linux/pkt_sched.h
+10
View File
@@ -569,6 +569,16 @@ struct tc_netem_gemodel {
#define NETEM_DIST_SCALE 8192
#define NETEM_DIST_MAX 16384
struct tc_netem_xstats {
__u64 delayed; /* packets delayed */
__u64 dropped; /* packets dropped by loss model */
__u64 corrupted; /* packets with bit errors injected */
__u64 duplicated; /* duplicate packets generated */
__u64 reordered; /* packets sent out of order */
__u64 ecn_marked; /* packets ECN CE-marked (not dropped)*/
__u64 allocation_errors;
};
/* DRR */
enum {
net/sched/sch_netem.c
+49 -6
View File
@@ -152,6 +152,15 @@ struct netem_sched_data {
u8 state;
} clg;
/* Impairment counters */
u64 delayed;
u64 dropped;
u64 corrupted;
u64 duplicated;
u64 ecn_marked;
u64 reordered;
u64 allocation_errors;
/* Cold tail: slot reschedule config and the watchdog timer. */
struct tc_netem_slot slot_config;
struct qdisc_watchdog watchdog;
@@ -462,16 +471,21 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
skb->prev = NULL;
/* Random duplication */
if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor, &q->prng))
if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor, &q->prng)) {
++count;
WRITE_ONCE(q->duplicated, q->duplicated + 1);
}
/* Drop packet? */
if (loss_event(q)) {
if (q->ecn && INET_ECN_set_ce(skb))
qdisc_qstats_drop(sch); /* mark packet */
else
if (q->ecn && INET_ECN_set_ce(skb)) {
WRITE_ONCE(q->ecn_marked, q->ecn_marked + 1);
} else {
WRITE_ONCE(q->dropped, q->dropped + 1);
--count;
}
}
if (count == 0) {
qdisc_qstats_drop(sch);
__qdisc_drop(skb, to_free);
@@ -488,8 +502,11 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
* If we need to duplicate packet, then clone it before
* original is modified.
*/
if (count > 1)
if (count > 1) {
skb2 = skb_clone(skb, GFP_ATOMIC);
if (!skb2)
WRITE_ONCE(q->allocation_errors, q->allocation_errors + 1);
}
/*
* Randomized packet corruption.
@@ -500,8 +517,10 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor, &q->prng)) {
if (skb_is_gso(skb)) {
skb = netem_segment(skb, sch, to_free);
if (!skb)
if (!skb) {
WRITE_ONCE(q->allocation_errors, q->allocation_errors + 1);
goto finish_segs;
}
segs = skb->next;
skb_mark_not_on_list(skb);
@@ -510,11 +529,13 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
skb = skb_unshare(skb, GFP_ATOMIC);
if (unlikely(!skb)) {
WRITE_ONCE(q->allocation_errors, q->allocation_errors + 1);
qdisc_qstats_drop(sch);
goto finish_segs;
}
if (skb_linearize(skb) ||
(skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))) {
WRITE_ONCE(q->allocation_errors, q->allocation_errors + 1);
qdisc_drop(skb, sch, to_free);
skb = NULL;
goto finish_segs;
@@ -523,6 +544,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
if (skb->len) {
u32 offset = get_random_u32_below(skb->len);
skb->data[offset] ^= 1 << get_random_u32_below(8);
WRITE_ONCE(q->corrupted, q->corrupted + 1);
}
}
@@ -604,12 +626,16 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
cb->time_to_send = now + delay;
++q->counter;
if (delay)
WRITE_ONCE(q->delayed, q->delayed + 1);
tfifo_enqueue(skb, sch);
} else {
/*
* Do re-ordering by putting one out of N packets at the front
* of the queue.
*/
WRITE_ONCE(q->reordered, q->reordered + 1);
cb->time_to_send = ktime_get_ns();
q->counter = 0;
@@ -1348,6 +1374,22 @@ nla_put_failure:
return -1;
}
static int netem_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
{
struct netem_sched_data *q = qdisc_priv(sch);
struct tc_netem_xstats st = {
.delayed = READ_ONCE(q->delayed),
.dropped = READ_ONCE(q->dropped),
.corrupted = READ_ONCE(q->corrupted),
.duplicated = READ_ONCE(q->duplicated),
.reordered = READ_ONCE(q->reordered),
.ecn_marked = READ_ONCE(q->ecn_marked),
.allocation_errors = READ_ONCE(q->allocation_errors),
};
return gnet_stats_copy_app(d, &st, sizeof(st));
}
static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
struct sk_buff *skb, struct tcmsg *tcm)
{
@@ -1410,6 +1452,7 @@ static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
.destroy = netem_destroy,
.change = netem_change,
.dump = netem_dump,
.dump_stats = netem_dump_stats,
.owner = THIS_MODULE,
};
MODULE_ALIAS_NET_SCH("netem");