Messages in this thread Patch in this message | | | From | Francois Michel <> | Subject | [PATCH net-next 3/3] [PATCH 3/3] netem: allow using seeded PRNG for correlated loss events | Date | Mon, 14 Aug 2023 04:31:40 +0200 |
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From: François Michel <francois.michel@uclouvain.be>
Use the netem_get_random_u32() function to generate correlated loss events of netem.
Signed-off-by: François Michel <francois.michel@uclouvain.be> --- net/sched/sch_netem.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index 1190782ef79d..da333c3d24ac 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -198,15 +198,15 @@ static void init_crandom(struct crndstate *state, unsigned long rho) * Next number depends on last value. * rho is scaled to avoid floating point. */ -static u32 get_crandom(struct crndstate *state) +static u32 get_crandom(struct crndstate *state, struct prng *p) { u64 value, rho; unsigned long answer; if (!state || state->rho == 0) /* no correlation */ - return get_random_u32(); + return netem_get_random_u32(p); - value = get_random_u32(); + value = netem_get_random_u32(p); rho = (u64)state->rho + 1; answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32; state->last = answer; @@ -309,7 +309,7 @@ static bool loss_event(struct netem_sched_data *q) switch (q->loss_model) { case CLG_RANDOM: /* Random packet drop 0 => none, ~0 => all */ - return q->loss && q->loss >= get_crandom(&q->loss_cor); + return q->loss && q->loss >= get_crandom(&q->loss_cor, &q->prng); case CLG_4_STATES: /* 4state loss model algorithm (used also for GI model) @@ -338,6 +338,7 @@ static bool loss_event(struct netem_sched_data *q) */ static s64 tabledist(s64 mu, s32 sigma, struct crndstate *state, + struct prng *prng, const struct disttable *dist) { s64 x; @@ -347,7 +348,7 @@ static s64 tabledist(s64 mu, s32 sigma, if (sigma == 0) return mu; - rnd = get_crandom(state); + rnd = get_crandom(state, prng); /* default uniform distribution */ if (dist == NULL) @@ -469,7 +470,7 @@ 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)) + if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor, &q->prng)) ++count; /* Drop packet? */ @@ -512,7 +513,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch, * If packet is going to be hardware checksummed, then * do it now in software before we mangle it. */ - if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) { + 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) @@ -550,12 +551,12 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch, cb = netem_skb_cb(skb); if (q->gap == 0 || /* not doing reordering */ q->counter < q->gap - 1 || /* inside last reordering gap */ - q->reorder < get_crandom(&q->reorder_cor)) { + q->reorder < get_crandom(&q->reorder_cor, &q->prng)) { u64 now; s64 delay; delay = tabledist(q->latency, q->jitter, - &q->delay_cor, q->delay_dist); + &q->delay_cor, &q->prng, q->delay_dist); now = ktime_get_ns(); @@ -659,7 +660,7 @@ static void get_slot_next(struct netem_sched_data *q, u64 now) else next_delay = tabledist(q->slot_config.dist_delay, (s32)(q->slot_config.dist_jitter), - NULL, q->slot_dist); + NULL, &q->prng, q->slot_dist); q->slot.slot_next = now + next_delay; q->slot.packets_left = q->slot_config.max_packets; -- 2.41.0
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