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>
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index 66d3b00..f4fb2d4 100644
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -88,7 +88,7 @@
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 @@
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 @@
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 @@
*/
/* 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 @@
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 @@
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;