tc: fq: support low_rate_threshold attribute

TCA_FQ_LOW_RATE_THRESHOLD sch_fq attribute was added in linux-4.9

Tested:

lpaa5:/tmp# tc -qd add dev eth1 root fq
lpaa5:/tmp# tc -s qd sh dev eth1
qdisc fq 8003: root refcnt 5 limit 10000p flow_limit 1000p buckets 4096 \
 orphan_mask 4095 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 quantum 3648 \
 initial_quantum 18240 low_rate_threshold 550Kbit refill_delay 40.0ms
 Sent 62139 bytes 395 pkt (dropped 0, overlimits 0 requeues 0)
 backlog 0b 0p requeues 0
  116 flows (114 inactive, 0 throttled)
  1 gc, 0 highprio, 0 throttled

lpaa5:/tmp# ./netperf -H lpaa6 -t TCP_RR -l10 -- -q 500000 -r 300,300 -o P99_LATENCY
99th Percentile Latency Microseconds
7081

lpaa5:/tmp# tc qd replace dev eth1 root fq low_rate_threshold 10Mbit
lpaa5:/tmp# ./netperf -H lpaa6 -t TCP_RR -l10 -- -q 500000 -r 300,300 -o P99_LATENCY
99th Percentile Latency Microseconds
858

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>

diff --git a/tc/q_fq.c b/tc/q_fq.c
index c9efbfc43632231c19754c1d8260da93bda2b5b7..45b2ffd9a6d32068cb9ee0e00b7be7d7875b8f96 100644 (file)
--- a/tc/q_fq.c
+++ b/tc/q_fq.c
@@ -55,6 +55,7 @@ static void explain(void)
        fprintf(stderr, "              [ quantum BYTES ] [ initial_quantum BYTES ]\n");
        fprintf(stderr, "              [ maxrate RATE  ] [ buckets NUMBER ]\n");
        fprintf(stderr, "              [ [no]pacing ] [ refill_delay TIME ]\n");
+       fprintf(stderr, "              [ low_rate_threshold RATE ]\n");
        fprintf(stderr, "              [ orphan_mask MASK]\n");
 }
 
@@ -79,6 +80,7 @@ static int fq_parse_opt(struct qdisc_util *qu, int argc, char **argv,
        unsigned int initial_quantum;
        unsigned int buckets = 0;
        unsigned int maxrate;
+       unsigned int low_rate_threshold;
        unsigned int defrate;
        unsigned int refill_delay;
        unsigned int orphan_mask;
@@ -90,6 +92,7 @@ static int fq_parse_opt(struct qdisc_util *qu, int argc, char **argv,
        bool set_defrate = false;
        bool set_refill_delay = false;
        bool set_orphan_mask = false;
+       bool set_low_rate_threshold = false;
        int pacing = -1;
        struct rtattr *tail;
 
@@ -121,6 +124,13 @@ static int fq_parse_opt(struct qdisc_util *qu, int argc, char **argv,
                                return -1;
                        }
                        set_maxrate = true;
+               } else if (strcmp(*argv, "low_rate_threshold") == 0) {
+                       NEXT_ARG();
+                       if (get_rate(&low_rate_threshold, *argv)) {
+                               fprintf(stderr, "Illegal \"low_rate_threshold\"\n");
+                               return -1;
+                       }
+                       set_low_rate_threshold = true;
                } else if (strcmp(*argv, "defrate") == 0) {
                        NEXT_ARG();
                        if (get_rate(&defrate, *argv)) {
@@ -196,6 +206,9 @@ static int fq_parse_opt(struct qdisc_util *qu, int argc, char **argv,
        if (set_maxrate)
                addattr_l(n, 1024, TCA_FQ_FLOW_MAX_RATE,
                          &maxrate, sizeof(maxrate));
+       if (set_low_rate_threshold)
+               addattr_l(n, 1024, TCA_FQ_LOW_RATE_THRESHOLD,
+                         &low_rate_threshold, sizeof(low_rate_threshold));
        if (set_defrate)
                addattr_l(n, 1024, TCA_FQ_FLOW_DEFAULT_RATE,
                          &defrate, sizeof(defrate));
@@ -276,6 +289,13 @@ static int fq_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
                if (rate != 0)
                        fprintf(f, "defrate %s ", sprint_rate(rate, b1));
        }
+       if (tb[TCA_FQ_LOW_RATE_THRESHOLD] &&
+           RTA_PAYLOAD(tb[TCA_FQ_LOW_RATE_THRESHOLD]) >= sizeof(__u32)) {
+               rate = rta_getattr_u32(tb[TCA_FQ_LOW_RATE_THRESHOLD]);
+
+               if (rate != 0)
+                       fprintf(f, "low_rate_threshold %s ", sprint_rate(rate, b1));
+       }
        if (tb[TCA_FQ_FLOW_REFILL_DELAY] &&
            RTA_PAYLOAD(tb[TCA_FQ_FLOW_REFILL_DELAY]) >= sizeof(__u32)) {
                refill_delay = rta_getattr_u32(tb[TCA_FQ_FLOW_REFILL_DELAY]);