UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

Merge branch 'tcp-tso-defer-improvements' 

Eric Dumazet says:

====================
tcp: tso defer improvements

This series makes tcp_tso_should_defer() a bit smarter :

1) MSG_EOR gives a hint to TCP to not defer some skbs

2) Second patch takes into account that head tstamp
   can be in the future.

3) Third patch uses existing high resolution state variables
   to have a more precise heuristic.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2018-11-11 13:54:54 -08:00
parent 5e13a0d3f5 a682850a11
commit 83afb36a70
1 changed files with 13 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
net/ipv4/tcp_output.c
View File

@ -1907,10 +1907,11 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
bool *is_cwnd_limited, u32 max_segs)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
u32 age, send_win, cong_win, limit, in_flight;
u32 send_win, cong_win, limit, in_flight;
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *head;
int win_divisor;
s64 delta;
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
goto send_now;
@ -1919,9 +1920,12 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
goto send_now;
/* Avoid bursty behavior by allowing defer
* only if the last write was recent.
* only if the last write was recent (1 ms).
* Note that tp->tcp_wstamp_ns can be in the future if we have
* packets waiting in a qdisc or device for EDT delivery.
*/
if ((s32)(tcp_jiffies32 - tp->lsndtime) > 0)
delta = tp->tcp_clock_cache - tp->tcp_wstamp_ns - NSEC_PER_MSEC;
if (delta > 0)
goto send_now;
in_flight = tcp_packets_in_flight(tp);
@ -1944,6 +1948,10 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
if ((skb != tcp_write_queue_tail(sk)) && (limit >= skb->len))
goto send_now;
/* If this packet won't get more data, do not wait. */
if (TCP_SKB_CB(skb)->eor)
goto send_now;
win_divisor = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tso_win_divisor);
if (win_divisor) {
u32 chunk = min(tp->snd_wnd, tp->snd_cwnd * tp->mss_cache);
@ -1968,9 +1976,9 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
head = tcp_rtx_queue_head(sk);
if (!head)
goto send_now;
age = tcp_stamp_us_delta(tp->tcp_mstamp, tcp_skb_timestamp_us(head));
delta = tp->tcp_clock_cache - head->tstamp;
/* If next ACK is likely to come too late (half srtt), do not defer */
if (age < (tp->srtt_us >> 4))
if ((s64)(delta - (u64)NSEC_PER_USEC * (tp->srtt_us >> 4)) < 0)
goto send_now;
/* Ok, it looks like it is advisable to defer. */