On 11/14/2017 09:28 AM, Stephen Hemminger wrote:
> Since times are now expressed in 64 bit nanosecond, need to now do
> true 64 bit divide. Change the name of the function to bette express
> the new units.
>
> Fixes: 99803171ef04 ("netem: add uapi to express delay and jitter in
> nanoseconds")
> Reported-by: Randy Dunlap <rdun...@infradead.org>
> Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
Hi Stephen,
I still get it. Maybe it's this % operator:
skb->data[prandom_u32() % skb_headlen(skb)] ^=
1<<(prandom_u32() % 8);
in net_enqueue().
> ---
> net/sched/sch_netem.c | 11 ++++-------
> 1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
> index b686e755fda9..644323d6081c 100644
> --- a/net/sched/sch_netem.c
> +++ b/net/sched/sch_netem.c
> @@ -339,10 +339,8 @@ static s64 tabledist(s64 mu, s64 sigma,
> return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu;
> }
>
> -static u64 packet_len_2_sched_time(unsigned int len,
> - struct netem_sched_data *q)
> +static u64 packet_time_ns(u64 len, const struct netem_sched_data *q)
> {
> - u64 offset;
> len += q->packet_overhead;
>
> if (q->cell_size) {
> @@ -352,9 +350,8 @@ static u64 packet_len_2_sched_time(unsigned int len,
> cells++;
> len = cells * (q->cell_size + q->cell_overhead);
> }
> - offset = (u64)len * NSEC_PER_SEC;
> - do_div(offset, q->rate);
> - return offset;
> +
> + return div64_u64(len * NSEC_PER_SEC, q->rate);
> }
>
> static void tfifo_reset(struct Qdisc *sch)
> @@ -556,7 +553,7 @@ static int netem_enqueue(struct sk_buff *skb, struct
> Qdisc *sch,
> now = last->time_to_send;
> }
>
> - delay += packet_len_2_sched_time(qdisc_pkt_len(skb), q);
> + delay += packet_time_ns(qdisc_pkt_len(skb), q);
> }
>
> cb->time_to_send = now + delay;
>
--
~Randy
