diff options
| author | Aananth V <aananthv@google.com> | 2023-09-14 14:36:21 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-09-16 13:42:34 +0100 |
| commit | 3868ab0f192581eff978501a05f3dc2e01541d77 (patch) | |
| tree | 5cd1330b779f689ecfc3e24b6fb8a5baa8600799 /include | |
| parent | e326578a21414738de45f77badd332fb00bd0f58 (diff) | |
tcp: new TCP_INFO stats for RTO events
The 2023 SIGCOMM paper "Improving Network Availability with Protective
ReRoute" has indicated Linux TCP's RTO-triggered txhash rehashing can
effectively reduce application disruption during outages. To better
measure the efficacy of this feature, this patch adds three more
detailed stats during RTO recovery and exports via TCP_INFO.
Applications and monitoring systems can leverage this data to measure
the network path diversity and end-to-end repair latency during network
outages to improve their network infrastructure.
The following counters are added to tcp_sock in order to track RTO
events over the lifetime of a TCP socket.
1. u16 total_rto - Counts the total number of RTO timeouts.
2. u16 total_rto_recoveries - Counts the total number of RTO recoveries.
3. u32 total_rto_time - Counts the total time spent (ms) in RTO
recoveries. (time spent in CA_Loss and
CA_Recovery states)
To compute total_rto_time, we add a new u32 rto_stamp field to
tcp_sock. rto_stamp records the start timestamp (ms) of the last RTO
recovery (CA_Loss).
Corresponding fields are also added to the tcp_info struct.
Signed-off-by: Aananth V <aananthv@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/tcp.h | 8 | ||||
| -rw-r--r-- | include/uapi/linux/tcp.h | 12 |
2 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 44d946161d4a..e15452df9804 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -377,6 +377,14 @@ struct tcp_sock { * Total data bytes retransmitted */ u32 total_retrans; /* Total retransmits for entire connection */ + u32 rto_stamp; /* Start time (ms) of last CA_Loss recovery */ + u16 total_rto; /* Total number of RTO timeouts, including + * SYN/SYN-ACK and recurring timeouts. + */ + u16 total_rto_recoveries; /* Total number of RTO recoveries, + * including any unfinished recovery. + */ + u32 total_rto_time; /* ms spent in (completed) RTO recoveries. */ u32 urg_seq; /* Seq of received urgent pointer */ unsigned int keepalive_time; /* time before keep alive takes place */ diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 879eeb0a084b..d1d08da6331a 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -289,6 +289,18 @@ struct tcp_info { */ __u32 tcpi_rehash; /* PLB or timeout triggered rehash attempts */ + + __u16 tcpi_total_rto; /* Total number of RTO timeouts, including + * SYN/SYN-ACK and recurring timeouts. + */ + __u16 tcpi_total_rto_recoveries; /* Total number of RTO + * recoveries, including any + * unfinished recovery. + */ + __u32 tcpi_total_rto_time; /* Total time spent in RTO recoveries + * in milliseconds, including any + * unfinished recovery. + */ }; /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */ |