diff options
| author | Eric Dumazet <edumazet@google.com> | 2020-04-30 10:35:43 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-04-30 13:24:01 -0700 |
| commit | a70437cc09a11771870e9f6bfc0ba1237161daa8 (patch) | |
| tree | 2160cfb6274072fcc4350afbbd5aa7ebf1580a4c | |
| parent | ccd0628fca440268711560a1dbacc727b4f9e214 (diff) | |
tcp: add hrtimer slack to sack compression
Add a sysctl to control hrtimer slack, default of 100 usec.
This gives the opportunity to reduce system overhead,
and help very short RTT flows.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | Documentation/networking/ip-sysctl.rst | 8 | ||||
| -rw-r--r-- | include/net/netns/ipv4.h | 1 | ||||
| -rw-r--r-- | net/ipv4/sysctl_net_ipv4.c | 7 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 5 | ||||
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 1 |
5 files changed, 20 insertions, 2 deletions
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index 3266aee9e052..50b440d29a13 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -651,6 +651,14 @@ tcp_comp_sack_delay_ns - LONG INTEGER Default : 1,000,000 ns (1 ms) +tcp_comp_sack_slack_ns - LONG INTEGER + This sysctl control the slack used when arming the + timer used by SACK compression. This gives extra time + for small RTT flows, and reduces system overhead by allowing + opportunistic reduction of timer interrupts. + + Default : 100,000 ns (100 us) + tcp_comp_sack_nr - INTEGER Max number of SACK that can be compressed. Using 0 disables SACK compression. diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h index 5acdb4d414c4..9e36738c1fe1 100644 --- a/include/net/netns/ipv4.h +++ b/include/net/netns/ipv4.h @@ -173,6 +173,7 @@ struct netns_ipv4 { int sysctl_tcp_rmem[3]; int sysctl_tcp_comp_sack_nr; unsigned long sysctl_tcp_comp_sack_delay_ns; + unsigned long sysctl_tcp_comp_sack_slack_ns; struct inet_timewait_death_row tcp_death_row; int sysctl_max_syn_backlog; int sysctl_tcp_fastopen; diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 95ad71e76cc3..3a628423d27b 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -1330,6 +1330,13 @@ static struct ctl_table ipv4_net_table[] = { .proc_handler = proc_doulongvec_minmax, }, { + .procname = "tcp_comp_sack_slack_ns", + .data = &init_net.ipv4.sysctl_tcp_comp_sack_slack_ns, + .maxlen = sizeof(unsigned long), + .mode = 0644, + .proc_handler = proc_doulongvec_minmax, + }, + { .procname = "tcp_comp_sack_nr", .data = &init_net.ipv4.sysctl_tcp_comp_sack_nr, .maxlen = sizeof(int), diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index ef921ecba415..d68128a672ab 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5324,8 +5324,9 @@ send_now: delay = min_t(unsigned long, sock_net(sk)->ipv4.sysctl_tcp_comp_sack_delay_ns, rtt * (NSEC_PER_USEC >> 3)/20); sock_hold(sk); - hrtimer_start(&tp->compressed_ack_timer, ns_to_ktime(delay), - HRTIMER_MODE_REL_PINNED_SOFT); + hrtimer_start_range_ns(&tp->compressed_ack_timer, ns_to_ktime(delay), + sock_net(sk)->ipv4.sysctl_tcp_comp_sack_slack_ns, + HRTIMER_MODE_REL_PINNED_SOFT); } static inline void tcp_ack_snd_check(struct sock *sk) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 83a5d24e13b8..6c05f1ceb538 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2780,6 +2780,7 @@ static int __net_init tcp_sk_init(struct net *net) sizeof(init_net.ipv4.sysctl_tcp_wmem)); } net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC; + net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC; net->ipv4.sysctl_tcp_comp_sack_nr = 44; net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE; spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock); |