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tcp_cubic: fix clock dependency 

The hystart code was written with assumption that HZ=1000.
Replace the use of jiffies with bictcp_clock as a millisecond
real time clock.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Reported-by: Lucas Nussbaum <lucas.nussbaum@loria.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
stephen hemminger 2011-03-14 07:52:15 +00:00 committed by David S. Miller
parent aac46324e1
commit 17a6e9f1aa
1 changed files with 19 additions and 12 deletions
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31
net/ipv4/tcp_cubic.c
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@ -88,7 +88,7 @@ struct bictcp {
u32 last_time; /* time when updated last_cwnd */
u32 bic_origin_point;/* origin point of bic function */
u32 bic_K; /* time to origin point from the beginning of the current epoch */
u32 delay_min; /* min delay */
u32 delay_min; /* min delay (msec << 3) */
u32 epoch_start; /* beginning of an epoch */
u32 ack_cnt; /* number of acks */
u32 tcp_cwnd; /* estimated tcp cwnd */
@ -98,7 +98,7 @@ struct bictcp {
u8 found; /* the exit point is found? */
u32 round_start; /* beginning of each round */
u32 end_seq; /* end_seq of the round */
u32 last_jiffies; /* last time when the ACK spacing is close */
u32 last_ack; /* last time when the ACK spacing is close */
u32 curr_rtt; /* the minimum rtt of current round */
};
@ -119,12 +119,21 @@ static inline void bictcp_reset(struct bictcp *ca)
ca->found = 0;
}
static inline u32 bictcp_clock(void)
{
#if HZ < 1000
return ktime_to_ms(ktime_get_real());
#else
return jiffies_to_msecs(jiffies);
#endif
}
static inline void bictcp_hystart_reset(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
struct bictcp *ca = inet_csk_ca(sk);
ca->round_start = ca->last_jiffies = jiffies;
ca->round_start = ca->last_ack = bictcp_clock();
ca->end_seq = tp->snd_nxt;
ca->curr_rtt = 0;
ca->sample_cnt = 0;
@ -239,8 +248,8 @@ static inline void bictcp_update(struct bictcp *ca, u32 cwnd)
*/
/* change the unit from HZ to bictcp_HZ */
t = ((tcp_time_stamp + (ca->delay_min>>3) - ca->epoch_start)
<< BICTCP_HZ) / HZ;
t = ((tcp_time_stamp + msecs_to_jiffies(ca->delay_min>>3)
- ca->epoch_start) << BICTCP_HZ) / HZ;
if (t < ca->bic_K) /* t - K */
offs = ca->bic_K - t;
@ -342,14 +351,12 @@ static void hystart_update(struct sock *sk, u32 delay)
struct bictcp *ca = inet_csk_ca(sk);
if (!(ca->found & hystart_detect)) {
u32 curr_jiffies = jiffies;
u32 now = bictcp_clock();
/* first detection parameter - ack-train detection */
if ((s32)(curr_jiffies - ca->last_jiffies) <=
msecs_to_jiffies(hystart_ack_delta)) {
ca->last_jiffies = curr_jiffies;
if ((s32) (curr_jiffies - ca->round_start) >
ca->delay_min >> 4)
if ((s32)(now - ca->last_ack) <= hystart_ack_delta) {
ca->last_ack = now;
if ((s32)(now - ca->round_start) > ca->delay_min >> 4)
ca->found |= HYSTART_ACK_TRAIN;
}
@ -396,7 +403,7 @@ static void bictcp_acked(struct sock *sk, u32 cnt, s32 rtt_us)
if ((s32)(tcp_time_stamp - ca->epoch_start) < HZ)
return;
delay = usecs_to_jiffies(rtt_us) << 3;
delay = (rtt_us << 3) / USEC_PER_MSEC;
if (delay == 0)
delay = 1;