diff options
Diffstat (limited to 'net/sched')
-rw-r--r-- | net/sched/sch_pie.c | 120 |
1 files changed, 99 insertions, 21 deletions
diff --git a/net/sched/sch_pie.c b/net/sched/sch_pie.c index df98a887eb89..b0b0dc46af61 100644 --- a/net/sched/sch_pie.c +++ b/net/sched/sch_pie.c @@ -22,6 +22,7 @@ #define QUEUE_THRESHOLD 16384 #define DQCOUNT_INVALID -1 +#define DTIME_INVALID 0xffffffffffffffff #define MAX_PROB 0xffffffffffffffff #define PIE_SCALE 8 @@ -34,6 +35,7 @@ struct pie_params { u32 beta; /* and are used for shift relative to 1 */ bool ecn; /* true if ecn is enabled */ bool bytemode; /* to scale drop early prob based on pkt size */ + u8 dq_rate_estimator; /* to calculate delay using Little's law */ }; /* variables used */ @@ -77,11 +79,34 @@ static void pie_params_init(struct pie_params *params) params->target = PSCHED_NS2TICKS(15 * NSEC_PER_MSEC); /* 15 ms */ params->ecn = false; params->bytemode = false; + params->dq_rate_estimator = false; +} + +/* private skb vars */ +struct pie_skb_cb { + psched_time_t enqueue_time; +}; + +static struct pie_skb_cb *get_pie_cb(const struct sk_buff *skb) +{ + qdisc_cb_private_validate(skb, sizeof(struct pie_skb_cb)); + return (struct pie_skb_cb *)qdisc_skb_cb(skb)->data; +} + +static psched_time_t pie_get_enqueue_time(const struct sk_buff *skb) +{ + return get_pie_cb(skb)->enqueue_time; +} + +static void pie_set_enqueue_time(struct sk_buff *skb) +{ + get_pie_cb(skb)->enqueue_time = psched_get_time(); } static void pie_vars_init(struct pie_vars *vars) { vars->dq_count = DQCOUNT_INVALID; + vars->dq_tstamp = DTIME_INVALID; vars->accu_prob = 0; vars->avg_dq_rate = 0; /* default of 150 ms in pschedtime */ @@ -172,6 +197,10 @@ static int pie_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch, /* we can enqueue the packet */ if (enqueue) { + /* Set enqueue time only when dq_rate_estimator is disabled. */ + if (!q->params.dq_rate_estimator) + pie_set_enqueue_time(skb); + q->stats.packets_in++; if (qdisc_qlen(sch) > q->stats.maxq) q->stats.maxq = qdisc_qlen(sch); @@ -194,6 +223,7 @@ static const struct nla_policy pie_policy[TCA_PIE_MAX + 1] = { [TCA_PIE_BETA] = {.type = NLA_U32}, [TCA_PIE_ECN] = {.type = NLA_U32}, [TCA_PIE_BYTEMODE] = {.type = NLA_U32}, + [TCA_PIE_DQ_RATE_ESTIMATOR] = {.type = NLA_U32}, }; static int pie_change(struct Qdisc *sch, struct nlattr *opt, @@ -247,6 +277,10 @@ static int pie_change(struct Qdisc *sch, struct nlattr *opt, if (tb[TCA_PIE_BYTEMODE]) q->params.bytemode = nla_get_u32(tb[TCA_PIE_BYTEMODE]); + if (tb[TCA_PIE_DQ_RATE_ESTIMATOR]) + q->params.dq_rate_estimator = + nla_get_u32(tb[TCA_PIE_DQ_RATE_ESTIMATOR]); + /* Drop excess packets if new limit is lower */ qlen = sch->q.qlen; while (sch->q.qlen > sch->limit) { @@ -266,6 +300,28 @@ static void pie_process_dequeue(struct Qdisc *sch, struct sk_buff *skb) { struct pie_sched_data *q = qdisc_priv(sch); int qlen = sch->qstats.backlog; /* current queue size in bytes */ + psched_time_t now = psched_get_time(); + u32 dtime = 0; + + /* If dq_rate_estimator is disabled, calculate qdelay using the + * packet timestamp. + */ + if (!q->params.dq_rate_estimator) { + q->vars.qdelay = now - pie_get_enqueue_time(skb); + + if (q->vars.dq_tstamp != DTIME_INVALID) + dtime = now - q->vars.dq_tstamp; + + q->vars.dq_tstamp = now; + + if (qlen == 0) + q->vars.qdelay = 0; + + if (dtime == 0) + return; + + goto burst_allowance_reduction; + } /* If current queue is about 10 packets or more and dq_count is unset * we have enough packets to calculate the drain rate. Save @@ -289,10 +345,10 @@ static void pie_process_dequeue(struct Qdisc *sch, struct sk_buff *skb) q->vars.dq_count += skb->len; if (q->vars.dq_count >= QUEUE_THRESHOLD) { - psched_time_t now = psched_get_time(); - u32 dtime = now - q->vars.dq_tstamp; u32 count = q->vars.dq_count << PIE_SCALE; + dtime = now - q->vars.dq_tstamp; + if (dtime == 0) return; @@ -317,14 +373,19 @@ static void pie_process_dequeue(struct Qdisc *sch, struct sk_buff *skb) q->vars.dq_tstamp = psched_get_time(); } - if (q->vars.burst_time > 0) { - if (q->vars.burst_time > dtime) - q->vars.burst_time -= dtime; - else - q->vars.burst_time = 0; - } + goto burst_allowance_reduction; } } + + return; + +burst_allowance_reduction: + if (q->vars.burst_time > 0) { + if (q->vars.burst_time > dtime) + q->vars.burst_time -= dtime; + else + q->vars.burst_time = 0; + } } static void calculate_probability(struct Qdisc *sch) @@ -332,19 +393,25 @@ static void calculate_probability(struct Qdisc *sch) struct pie_sched_data *q = qdisc_priv(sch); u32 qlen = sch->qstats.backlog; /* queue size in bytes */ psched_time_t qdelay = 0; /* in pschedtime */ - psched_time_t qdelay_old = q->vars.qdelay; /* in pschedtime */ + psched_time_t qdelay_old = 0; /* in pschedtime */ s64 delta = 0; /* determines the change in probability */ u64 oldprob; u64 alpha, beta; u32 power; bool update_prob = true; - q->vars.qdelay_old = q->vars.qdelay; + if (q->params.dq_rate_estimator) { + qdelay_old = q->vars.qdelay; + q->vars.qdelay_old = q->vars.qdelay; - if (q->vars.avg_dq_rate > 0) - qdelay = (qlen << PIE_SCALE) / q->vars.avg_dq_rate; - else - qdelay = 0; + if (q->vars.avg_dq_rate > 0) + qdelay = (qlen << PIE_SCALE) / q->vars.avg_dq_rate; + else + qdelay = 0; + } else { + qdelay = q->vars.qdelay; + qdelay_old = q->vars.qdelay_old; + } /* If qdelay is zero and qlen is not, it means qlen is very small, less * than dequeue_rate, so we do not update probabilty in this round @@ -430,14 +497,18 @@ static void calculate_probability(struct Qdisc *sch) /* We restart the measurement cycle if the following conditions are met * 1. If the delay has been low for 2 consecutive Tupdate periods * 2. Calculated drop probability is zero - * 3. We have atleast one estimate for the avg_dq_rate ie., - * is a non-zero value + * 3. If average dq_rate_estimator is enabled, we have atleast one + * estimate for the avg_dq_rate ie., is a non-zero value */ if ((q->vars.qdelay < q->params.target / 2) && (q->vars.qdelay_old < q->params.target / 2) && q->vars.prob == 0 && - q->vars.avg_dq_rate > 0) + (!q->params.dq_rate_estimator || q->vars.avg_dq_rate > 0)) { pie_vars_init(&q->vars); + } + + if (!q->params.dq_rate_estimator) + q->vars.qdelay_old = qdelay; } static void pie_timer(struct timer_list *t) @@ -497,7 +568,9 @@ static int pie_dump(struct Qdisc *sch, struct sk_buff *skb) nla_put_u32(skb, TCA_PIE_ALPHA, q->params.alpha) || nla_put_u32(skb, TCA_PIE_BETA, q->params.beta) || nla_put_u32(skb, TCA_PIE_ECN, q->params.ecn) || - nla_put_u32(skb, TCA_PIE_BYTEMODE, q->params.bytemode)) + nla_put_u32(skb, TCA_PIE_BYTEMODE, q->params.bytemode) || + nla_put_u32(skb, TCA_PIE_DQ_RATE_ESTIMATOR, + q->params.dq_rate_estimator)) goto nla_put_failure; return nla_nest_end(skb, opts); @@ -514,9 +587,6 @@ static int pie_dump_stats(struct Qdisc *sch, struct gnet_dump *d) .prob = q->vars.prob, .delay = ((u32)PSCHED_TICKS2NS(q->vars.qdelay)) / NSEC_PER_USEC, - /* unscale and return dq_rate in bytes per sec */ - .avg_dq_rate = q->vars.avg_dq_rate * - (PSCHED_TICKS_PER_SEC) >> PIE_SCALE, .packets_in = q->stats.packets_in, .overlimit = q->stats.overlimit, .maxq = q->stats.maxq, @@ -524,6 +594,14 @@ static int pie_dump_stats(struct Qdisc *sch, struct gnet_dump *d) .ecn_mark = q->stats.ecn_mark, }; + /* avg_dq_rate is only valid if dq_rate_estimator is enabled */ + st.dq_rate_estimating = q->params.dq_rate_estimator; + + /* unscale and return dq_rate in bytes per sec */ + if (q->params.dq_rate_estimator) + st.avg_dq_rate = q->vars.avg_dq_rate * + (PSCHED_TICKS_PER_SEC) >> PIE_SCALE; + return gnet_stats_copy_app(d, &st, sizeof(st)); } |