740b0f1841
Upcoming congestion controls for TCP require usec resolution for RTT
estimations. Millisecond resolution is simply not enough these days.
FQ/pacing in DC environments also require this change for finer control
and removal of bimodal behavior due to the current hack in
tcp_update_pacing_rate() for 'small rtt'
TCP_CONG_RTT_STAMP is no longer needed.
As Julian Anastasov pointed out, we need to keep user compatibility :
tcp_metrics used to export RTT and RTTVAR in msec resolution,
so we added RTT_US and RTTVAR_US. An iproute2 patch is needed
to use the new attributes if provided by the kernel.
In this example ss command displays a srtt of 32 usecs (10Gbit link)
lpk51:~# ./ss -i dst lpk52
Netid State Recv-Q Send-Q Local Address:Port Peer
Address:Port
tcp ESTAB 0 1 10.246.11.51:42959
10.246.11.52:64614
cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448
cwnd:10 send
3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559
Updated iproute2 ip command displays :
lpk51:~# ./ip tcp_metrics | grep 10.246.11.52
10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source
10.246.11.51
Old binary displays :
lpk51:~# ip tcp_metrics | grep 10.246.11.52
10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source
10.246.11.51
With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Larry Brakmo <brakmo@google.com>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>
60 lines
1.4 KiB
C
60 lines
1.4 KiB
C
/* tcp_metrics.h - TCP Metrics Interface */
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#ifndef _LINUX_TCP_METRICS_H
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#define _LINUX_TCP_METRICS_H
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#include <linux/types.h>
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/* NETLINK_GENERIC related info
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*/
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#define TCP_METRICS_GENL_NAME "tcp_metrics"
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#define TCP_METRICS_GENL_VERSION 0x1
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enum tcp_metric_index {
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TCP_METRIC_RTT, /* in ms units */
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TCP_METRIC_RTTVAR, /* in ms units */
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TCP_METRIC_SSTHRESH,
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TCP_METRIC_CWND,
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TCP_METRIC_REORDERING,
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TCP_METRIC_RTT_US, /* in usec units */
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TCP_METRIC_RTTVAR_US, /* in usec units */
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/* Always last. */
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__TCP_METRIC_MAX,
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};
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#define TCP_METRIC_MAX (__TCP_METRIC_MAX - 1)
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enum {
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TCP_METRICS_ATTR_UNSPEC,
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TCP_METRICS_ATTR_ADDR_IPV4, /* u32 */
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TCP_METRICS_ATTR_ADDR_IPV6, /* binary */
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TCP_METRICS_ATTR_AGE, /* msecs */
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TCP_METRICS_ATTR_TW_TSVAL, /* u32, raw, rcv tsval */
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TCP_METRICS_ATTR_TW_TS_STAMP, /* s32, sec age */
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TCP_METRICS_ATTR_VALS, /* nested +1, u32 */
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TCP_METRICS_ATTR_FOPEN_MSS, /* u16 */
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TCP_METRICS_ATTR_FOPEN_SYN_DROPS, /* u16, count of drops */
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TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS, /* msecs age */
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TCP_METRICS_ATTR_FOPEN_COOKIE, /* binary */
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TCP_METRICS_ATTR_SADDR_IPV4, /* u32 */
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TCP_METRICS_ATTR_SADDR_IPV6, /* binary */
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__TCP_METRICS_ATTR_MAX,
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};
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#define TCP_METRICS_ATTR_MAX (__TCP_METRICS_ATTR_MAX - 1)
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enum {
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TCP_METRICS_CMD_UNSPEC,
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TCP_METRICS_CMD_GET,
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TCP_METRICS_CMD_DEL,
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__TCP_METRICS_CMD_MAX,
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};
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#define TCP_METRICS_CMD_MAX (__TCP_METRICS_CMD_MAX - 1)
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#endif /* _LINUX_TCP_METRICS_H */
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