FQ-PIE schedules independent PIE controllers per flow but exposes no
per-flow AQM state. Without class-level statistics there is no way to
observe the per-flow drop probability, queue delay, deficit or
dequeue rate from userspace.
Extend tc_fq_pie_xstats with a discriminated union, following the
same pattern established by FQ-CoDel (TCA_FQ_CODEL_XSTATS_CLASS):
- Rename the existing flat struct to tc_fq_pie_qd_stats.
- Add tc_fq_pie_cl_stats with per-flow prob, delay, deficit,
avg_dq_rate, and dq_rate_estimating fields.
- Wrap both in tc_fq_pie_xstats with a type discriminator
(TCA_FQ_PIE_XSTATS_QDISC / TCA_FQ_PIE_XSTATS_CLASS).
Wire up fq_pie_class_ops (.walk, .dump, .dump_stats) so that
'tc -s class show' against an fq_pie qdisc reports per-flow state:
prob per-flow PIE drop probability
delay per-flow queue sojourn time (microseconds)
deficit remaining DRR byte credits (signed integer)
avg_dq_rate dequeue rate estimate in bytes/second
(dq_rate_estimator mode only)
dq_rate_estimating flag indicating active delay estimation mode
Note: this changes the on-wire layout of tc_fq_pie_xstats. The type
field now occupies the first four bytes, displacing the former
packets_in field. Userspace must be updated concurrently; the
companion iproute2 patch handles this.
Fix the 'delay' field comment in struct tc_pie_xstats from "in ms" to
"in microseconds" to match the kernel's
PSCHED_TICKS2NS / NSEC_PER_USEC conversion.
Also correct the avg_dq_rate comment in tc_pie_xstats from
"bits/pie_time" to "bytes/second" to match the actual kernel
conversion (avg_dq_rate * PSCHED_TICKS_PER_SEC >> PIE_SCALE).
Signed-off-by: Hemendra M. Naik <[email protected]>
Signed-off-by: Vishal Kamath <[email protected]>
Signed-off-by: Mohit P. Tahiliani <[email protected]>
---
include/uapi/linux/pkt_sched.h | 29 +++++-
net/sched/sch_fq_pie.c | 131 ++++++++++++++++++++++++---
tools/include/uapi/linux/pkt_sched.h | 4 +-
3 files changed, 146 insertions(+), 18 deletions(-)
diff --git a/include/uapi/linux/pkt_sched.h b/include/uapi/linux/pkt_sched.h
index 66e8072f44df..0ad895edcb07 100644
--- a/include/uapi/linux/pkt_sched.h
+++ b/include/uapi/linux/pkt_sched.h
@@ -910,9 +910,9 @@ enum {
struct tc_pie_xstats {
__u64 prob; /* current probability */
- __u32 delay; /* current delay in ms */
+ __u32 delay; /* current delay in microseconds */
__u32 avg_dq_rate; /* current average dq_rate in
- * bits/pie_time
+ * bytes/second
*/
__u32 dq_rate_estimating; /* is avg_dq_rate being calculated? */
__u32 packets_in; /* total number of packets enqueued */
@@ -943,7 +943,12 @@ enum {
};
#define TCA_FQ_PIE_MAX (__TCA_FQ_PIE_MAX - 1)
-struct tc_fq_pie_xstats {
+enum {
+ TCA_FQ_PIE_XSTATS_QDISC,
+ TCA_FQ_PIE_XSTATS_CLASS,
+};
+
+struct tc_fq_pie_qd_stats {
__u32 packets_in; /* total number of packets enqueued */
__u32 dropped; /* packets dropped due to fq_pie_action */
__u32 overlimit; /* dropped due to lack of space in queue */
@@ -955,6 +960,24 @@ struct tc_fq_pie_xstats {
__u32 memory_usage; /* total memory across all queues */
};
+struct tc_fq_pie_cl_stats {
+ __u64 prob; /* current probability */
+ __u32 delay; /* current delay in microseconds */
+ __s32 deficit; /* number of remaining byte credits */
+ __u32 avg_dq_rate; /* current average dq_rate in
+ * bytes/second
+ */
+ __u32 dq_rate_estimating; /* is avg_dq_rate being calculated? */
+};
+
+struct tc_fq_pie_xstats {
+ __u32 type;
+ union {
+ struct tc_fq_pie_qd_stats qdisc_stats;
+ struct tc_fq_pie_cl_stats class_stats;
+ };
+};
+
/* CBS */
struct tc_cbs_qopt {
__u8 offload;
diff --git a/net/sched/sch_fq_pie.c b/net/sched/sch_fq_pie.c
index 7becbf5362b3..d22c4e02d2d9 100644
--- a/net/sched/sch_fq_pie.c
+++ b/net/sched/sch_fq_pie.c
@@ -330,7 +330,7 @@ static int fq_pie_change(struct Qdisc *sch, struct nlattr
*opt,
/* tupdate is in jiffies */
if (tb[TCA_FQ_PIE_TUPDATE])
WRITE_ONCE(q->p_params.tupdate,
- usecs_to_jiffies(nla_get_u32(tb[TCA_FQ_PIE_TUPDATE])));
+
usecs_to_jiffies(nla_get_u32(tb[TCA_FQ_PIE_TUPDATE])));
if (tb[TCA_FQ_PIE_ALPHA])
WRITE_ONCE(q->p_params.alpha,
@@ -509,24 +509,25 @@ static int fq_pie_dump(struct Qdisc *sch, struct sk_buff
*skb)
static int fq_pie_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
{
struct fq_pie_sched_data *q = qdisc_priv(sch);
- struct tc_fq_pie_xstats st = { 0 };
+ struct tc_fq_pie_xstats st = {
+ .type = TCA_FQ_PIE_XSTATS_QDISC,
+ };
struct list_head *pos;
- sch_tree_lock(sch);
-
- st.packets_in = q->stats.packets_in;
- st.overlimit = q->stats.overlimit;
- st.overmemory = q->overmemory;
- st.dropped = q->stats.dropped;
- st.ecn_mark = q->stats.ecn_mark;
- st.new_flow_count = q->new_flow_count;
- st.memory_usage = q->memory_usage;
+ st.qdisc_stats.packets_in = q->stats.packets_in;
+ st.qdisc_stats.overlimit = q->stats.overlimit;
+ st.qdisc_stats.overmemory = q->overmemory;
+ st.qdisc_stats.dropped = q->stats.dropped;
+ st.qdisc_stats.ecn_mark = q->stats.ecn_mark;
+ st.qdisc_stats.new_flow_count = q->new_flow_count;
+ st.qdisc_stats.memory_usage = q->memory_usage;
+ sch_tree_lock(sch);
list_for_each(pos, &q->new_flows)
- st.new_flows_len++;
+ st.qdisc_stats.new_flows_len++;
list_for_each(pos, &q->old_flows)
- st.old_flows_len++;
+ st.qdisc_stats.old_flows_len++;
sch_tree_unlock(sch);
return gnet_stats_copy_app(d, &st, sizeof(st));
@@ -561,7 +562,111 @@ static void fq_pie_destroy(struct Qdisc *sch)
kvfree(q->flows);
}
+static struct Qdisc *fq_pie_leaf(struct Qdisc *sch, unsigned long arg)
+{
+ return NULL;
+}
+
+static unsigned long fq_pie_find(struct Qdisc *sch, u32 classid)
+{
+ return 0;
+}
+
+static unsigned long fq_pie_bind(struct Qdisc *sch, unsigned long parent,
+ u32 classid)
+{
+ return 0;
+}
+
+static void fq_pie_unbind(struct Qdisc *q, unsigned long cl)
+{
+}
+
+static struct tcf_block *fq_pie_tcf_block(struct Qdisc *sch, unsigned long cl,
+ struct netlink_ext_ack *extack)
+{
+ struct fq_pie_sched_data *q = qdisc_priv(sch);
+
+ if (cl)
+ return NULL;
+ return q->block;
+}
+
+static int fq_pie_dump_class(struct Qdisc *sch, unsigned long cl,
+ struct sk_buff *skb, struct tcmsg *tcm)
+{
+ tcm->tcm_handle |= TC_H_MIN(cl);
+ return 0;
+}
+
+static int fq_pie_dump_class_stats(struct Qdisc *sch, unsigned long cl,
+ struct gnet_dump *d)
+{
+ struct fq_pie_sched_data *q = qdisc_priv(sch);
+ struct gnet_stats_queue qs = { 0 };
+ struct tc_fq_pie_xstats xstats;
+ u32 idx = cl - 1;
+
+ if (idx < q->flows_cnt) {
+ const struct fq_pie_flow *flow = &q->flows[idx];
+
+ memset(&xstats, 0, sizeof(xstats));
+ xstats.type = TCA_FQ_PIE_XSTATS_CLASS;
+ xstats.class_stats.prob = READ_ONCE(flow->vars.prob) <<
BITS_PER_BYTE;
+ xstats.class_stats.delay =
+ ((u32)PSCHED_TICKS2NS(READ_ONCE(flow->vars.qdelay))) /
+ NSEC_PER_USEC;
+ xstats.class_stats.deficit = READ_ONCE(flow->deficit);
+ xstats.class_stats.dq_rate_estimating =
+ READ_ONCE(q->p_params.dq_rate_estimator);
+
+ if (xstats.class_stats.dq_rate_estimating) {
+ xstats.class_stats.avg_dq_rate =
+ READ_ONCE(flow->vars.avg_dq_rate) *
+ (PSCHED_TICKS_PER_SEC) >> PIE_SCALE;
+ }
+
+ qs.qlen = READ_ONCE(flow->qlen);
+ qs.backlog = READ_ONCE(flow->backlog);
+ }
+ if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)
+ return -1;
+ if (idx < q->flows_cnt)
+ return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
+ return 0;
+}
+
+static void fq_pie_walk(struct Qdisc *sch, struct qdisc_walker *arg)
+{
+ struct fq_pie_sched_data *q = qdisc_priv(sch);
+ unsigned int i;
+
+ if (arg->stop)
+ return;
+
+ for (i = 0; i < q->flows_cnt; i++) {
+ if (list_empty(&q->flows[i].flowchain)) {
+ arg->count++;
+ continue;
+ }
+ if (!tc_qdisc_stats_dump(sch, i + 1, arg))
+ break;
+ }
+}
+
+static const struct Qdisc_class_ops fq_pie_class_ops = {
+ .leaf = fq_pie_leaf,
+ .find = fq_pie_find,
+ .tcf_block = fq_pie_tcf_block,
+ .bind_tcf = fq_pie_bind,
+ .unbind_tcf = fq_pie_unbind,
+ .dump = fq_pie_dump_class,
+ .dump_stats = fq_pie_dump_class_stats,
+ .walk = fq_pie_walk,
+};
+
static struct Qdisc_ops fq_pie_qdisc_ops __read_mostly = {
+ .cl_ops = &fq_pie_class_ops,
.id = "fq_pie",
.priv_size = sizeof(struct fq_pie_sched_data),
.enqueue = fq_pie_qdisc_enqueue,
diff --git a/tools/include/uapi/linux/pkt_sched.h
b/tools/include/uapi/linux/pkt_sched.h
index 587481a19433..9bc190f0b3cf 100644
--- a/tools/include/uapi/linux/pkt_sched.h
+++ b/tools/include/uapi/linux/pkt_sched.h
@@ -847,8 +847,8 @@ enum {
struct tc_pie_xstats {
__u32 prob; /* current probability */
- __u32 delay; /* current delay in ms */
- __u32 avg_dq_rate; /* current average dq_rate in bits/pie_time */
+ __u32 delay; /* current delay in microseconds */
+ __u32 avg_dq_rate; /* current average dq_rate in bytes/second */
__u32 packets_in; /* total number of packets enqueued */
__u32 dropped; /* packets dropped due to pie_action */
__u32 overlimit; /* dropped due to lack of space in queue */
--
2.34.1
