diff options
| author | David S. Miller <davem@davemloft.net> | 2023-10-23 09:35:02 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-10-23 09:35:02 +0100 |
| commit | bdf24b4bdfa59b124f9d0ff837f8d35a908da3b8 (patch) | |
| tree | be82eb8c966ea4a7efa7cd6ed0df9d8968ed9f5d /include/linux/tcp.h | |
| parent | 35c1b273206346c4178928b1121675dc143e61d2 (diff) | |
| parent | a77a0f5c7f23a8a4981a2a3ff47baa91ceaf1f53 (diff) | |
Merge branch 'tcp-ts-usec-resolution'
Eric Dumazet says:
====================
tcp: add optional usec resolution to TCP TS
As discussed in various public places in 2016, Google adopted
usec resolution in RFC 7323 TS values, at Van Jacobson suggestion.
Goals were :
1) better observability of delays in networking stacks/fabrics.
2) better disambiguation of events based on TSval/ecr values.
3) building block for congestion control modules needing usec resolution.
Back then we implemented a schem based on private SYN options
to safely negotiate the feature.
For upstream submission, we chose to use a much simpler route
attribute because this feature is probably going to be used
in private networks.
ip route add 10/8 ... features tcp_usec_ts
References:
https://www.ietf.org/proceedings/97/slides/slides-97-tcpm-tcp-options-for-low-latency-00.pdf
https://datatracker.ietf.org/doc/draft-wang-tcpm-low-latency-opt/
First two patches are fixing old minor bugs and might be taken
by stable teams (thanks to appropriate Fixes: tags)
====================
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/tcp.h')
| -rw-r--r-- | include/linux/tcp.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h index e15452df9804..6df715b6e51d 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -152,6 +152,7 @@ struct tcp_request_sock { u64 snt_synack; /* first SYNACK sent time */ bool tfo_listener; bool is_mptcp; + s8 req_usec_ts; #if IS_ENABLED(CONFIG_MPTCP) bool drop_req; #endif @@ -257,7 +258,8 @@ struct tcp_sock { u8 compressed_ack; u8 dup_ack_counter:2, tlp_retrans:1, /* TLP is a retransmission */ - unused:5; + tcp_usec_ts:1, /* TSval values in usec */ + unused:4; u32 chrono_start; /* Start time in jiffies of a TCP chrono */ u32 chrono_stat[3]; /* Time in jiffies for chrono_stat stats */ u8 chrono_type:2, /* current chronograph type */ @@ -576,4 +578,9 @@ void tcp_sock_set_quickack(struct sock *sk, int val); int tcp_sock_set_syncnt(struct sock *sk, int val); int tcp_sock_set_user_timeout(struct sock *sk, int val); +static inline bool dst_tcp_usec_ts(const struct dst_entry *dst) +{ + return dst_feature(dst, RTAX_FEATURE_TCP_USEC_TS); +} + #endif /* _LINUX_TCP_H */ |