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tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING

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This patch exports the sender chronograph stats via the socket
SO_TIMESTAMPING channel. Currently we can instrument how long a
particular application unit of data was queued in TCP by tracking
SOF_TIMESTAMPING_TX_SOFTWARE and SOF_TIMESTAMPING_TX_SCHED. Having
these sender chronograph stats exported simultaneously along with
these timestamps allow further breaking down the various sender
limitation.  For example, a video server can tell if a particular
chunk of video on a connection takes a long time to deliver because
TCP was experiencing small receive window. It is not possible to
tell before this patch without packet traces.

To prepare these stats, the user needs to set
SOF_TIMESTAMPING_OPT_STATS and SOF_TIMESTAMPING_OPT_TSONLY flags
while requesting other SOF_TIMESTAMPING TX timestamps. When the
timestamps are available in the error queue, the stats are returned
in a separate control message of type SCM_TIMESTAMPING_OPT_STATS,
in a list of TLVs (struct nlattr) of types: TCP_NLA_BUSY_TIME,
TCP_NLA_RWND_LIMITED, TCP_NLA_SNDBUF_LIMITED. Unit is microsecond.

Signed-off-by: Francis Yan <francisyyan@gmail.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Francis Yan 2016-11-27 23:07:18 -08:00 committed by David S. Miller
parent efd9017416
commit 1c885808e4
20 changed files with 90 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
Documentation/networking/timestamping.txt
View File

@ -182,6 +182,16 @@ SOF_TIMESTAMPING_OPT_TSONLY:
the timestamp even if sysctl net.core.tstamp_allow_data is 0.
This option disables SOF_TIMESTAMPING_OPT_CMSG.
SOF_TIMESTAMPING_OPT_STATS:
Optional stats that are obtained along with the transmit timestamps.
It must be used together with SOF_TIMESTAMPING_OPT_TSONLY. When the
transmit timestamp is available, the stats are available in a
separate control message of type SCM_TIMESTAMPING_OPT_STATS, as a
list of TLVs (struct nlattr) of types. These stats allow the
application to associate various transport layer stats with
the transmit timestamps, such as how long a certain block of
data was limited by peer's receiver window.
New applications are encouraged to pass SOF_TIMESTAMPING_OPT_ID to
disambiguate timestamps and SOF_TIMESTAMPING_OPT_TSONLY to operate

2
arch/alpha/include/uapi/asm/socket.h
View File

@ -97,4 +97,6 @@
#define SO_CNX_ADVICE 53
#define SCM_TIMESTAMPING_OPT_STATS 54
#endif /* _UAPI_ASM_SOCKET_H */

2
arch/frv/include/uapi/asm/socket.h
View File

@ -90,5 +90,7 @@
#define SO_CNX_ADVICE 53
#define SCM_TIMESTAMPING_OPT_STATS 54
#endif /* _ASM_SOCKET_H */

2
arch/ia64/include/uapi/asm/socket.h
View File

@ -99,4 +99,6 @@
#define SO_CNX_ADVICE 53
#define SCM_TIMESTAMPING_OPT_STATS 54
#endif /* _ASM_IA64_SOCKET_H */

2
arch/m32r/include/uapi/asm/socket.h
View File

@ -90,4 +90,6 @@
#define SO_CNX_ADVICE 53
#define SCM_TIMESTAMPING_OPT_STATS 54
#endif /* _ASM_M32R_SOCKET_H */

2
arch/mips/include/uapi/asm/socket.h
View File

@ -108,4 +108,6 @@
#define SO_CNX_ADVICE 53
#define SCM_TIMESTAMPING_OPT_STATS 54
#endif /* _UAPI_ASM_SOCKET_H */

2
arch/mn10300/include/uapi/asm/socket.h
View File

@ -90,4 +90,6 @@
#define SO_CNX_ADVICE 53
#define SCM_TIMESTAMPING_OPT_STATS 54
#endif /* _ASM_SOCKET_H */

2
arch/parisc/include/uapi/asm/socket.h
View File

@ -89,4 +89,6 @@
#define SO_CNX_ADVICE 0x402E
#define SCM_TIMESTAMPING_OPT_STATS 0x402F
#endif /* _UAPI_ASM_SOCKET_H */

2
arch/powerpc/include/uapi/asm/socket.h
View File

@ -97,4 +97,6 @@
#define SO_CNX_ADVICE 53
#define SCM_TIMESTAMPING_OPT_STATS 54
#endif /* _ASM_POWERPC_SOCKET_H */

2
arch/s390/include/uapi/asm/socket.h
View File

@ -96,4 +96,6 @@
#define SO_CNX_ADVICE 53
#define SCM_TIMESTAMPING_OPT_STATS 54
#endif /* _ASM_SOCKET_H */

2
arch/sparc/include/uapi/asm/socket.h
View File

@ -86,6 +86,8 @@
#define SO_CNX_ADVICE 0x0037
#define SCM_TIMESTAMPING_OPT_STATS 0x0038
/* Security levels - as per NRL IPv6 - don't actually do anything */
#define SO_SECURITY_AUTHENTICATION 0x5001
#define SO_SECURITY_ENCRYPTION_TRANSPORT 0x5002

2
arch/xtensa/include/uapi/asm/socket.h
View File

@ -101,4 +101,6 @@
#define SO_CNX_ADVICE 53
#define SCM_TIMESTAMPING_OPT_STATS 54
#endif /* _XTENSA_SOCKET_H */

2
include/linux/tcp.h
View File

@ -428,4 +428,6 @@ static inline void tcp_saved_syn_free(struct tcp_sock *tp)
tp->saved_syn = NULL;
}
struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk);
#endif /* _LINUX_TCP_H */

2
include/uapi/asm-generic/socket.h
View File

@ -92,4 +92,6 @@
#define SO_CNX_ADVICE 53
#define SCM_TIMESTAMPING_OPT_STATS 54
#endif /* __ASM_GENERIC_SOCKET_H */

3
include/uapi/linux/net_tstamp.h
View File

@ -25,8 +25,9 @@ enum {
SOF_TIMESTAMPING_TX_ACK = (1<<9),
SOF_TIMESTAMPING_OPT_CMSG = (1<<10),
SOF_TIMESTAMPING_OPT_TSONLY = (1<<11),
SOF_TIMESTAMPING_OPT_STATS = (1<<12),
SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_TSONLY,
SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_STATS,
SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) |
SOF_TIMESTAMPING_LAST
};

8
include/uapi/linux/tcp.h
View File

@ -220,6 +220,14 @@ struct tcp_info {
__u64 tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */
};
/* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
enum {
TCP_NLA_PAD,
TCP_NLA_BUSY, /* Time (usec) busy sending data */
TCP_NLA_RWND_LIMITED, /* Time (usec) limited by receive window */
TCP_NLA_SNDBUF_LIMITED, /* Time (usec) limited by send buffer */
};
/* for TCP_MD5SIG socket option */
#define TCP_MD5SIG_MAXKEYLEN 80

14
net/core/skbuff.c
View File

@ -3839,10 +3839,18 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb,
if (!skb_may_tx_timestamp(sk, tsonly))
return;
if (tsonly)
skb = alloc_skb(0, GFP_ATOMIC);
else
if (tsonly) {
#ifdef CONFIG_INET
if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS) &&
sk->sk_protocol == IPPROTO_TCP &&
sk->sk_type == SOCK_STREAM)
skb = tcp_get_timestamping_opt_stats(sk);
else
#endif
skb = alloc_skb(0, GFP_ATOMIC);
} else {
skb = skb_clone(orig_skb, GFP_ATOMIC);
}
if (!skb)
return;

7
net/core/sock.c
View File

@ -854,6 +854,13 @@ set_rcvbuf:
sk->sk_tskey = 0;
}
}
if (val & SOF_TIMESTAMPING_OPT_STATS &&
!(val & SOF_TIMESTAMPING_OPT_TSONLY)) {
ret = -EINVAL;
break;
}
sk->sk_tsflags = val;
if (val & SOF_TIMESTAMPING_RX_SOFTWARE)
sock_enable_timestamp(sk,

20
net/ipv4/tcp.c
View File

@ -2841,6 +2841,26 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
}
EXPORT_SYMBOL_GPL(tcp_get_info);
struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *stats;
struct tcp_info info;
stats = alloc_skb(3 * nla_total_size_64bit(sizeof(u64)), GFP_ATOMIC);
if (!stats)
return NULL;
tcp_get_info_chrono_stats(tp, &info);
nla_put_u64_64bit(stats, TCP_NLA_BUSY,
info.tcpi_busy_time, TCP_NLA_PAD);
nla_put_u64_64bit(stats, TCP_NLA_RWND_LIMITED,
info.tcpi_rwnd_limited, TCP_NLA_PAD);
nla_put_u64_64bit(stats, TCP_NLA_SNDBUF_LIMITED,
info.tcpi_sndbuf_limited, TCP_NLA_PAD);
return stats;
}
static int do_tcp_getsockopt(struct sock *sk, int level,
int optname, char __user *optval, int __user *optlen)
{

7
net/socket.c
View File

@ -693,9 +693,14 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
(sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) &&
ktime_to_timespec_cond(shhwtstamps->hwtstamp, tss.ts + 2))
empty = 0;
if (!empty)
if (!empty) {
put_cmsg(msg, SOL_SOCKET,
SCM_TIMESTAMPING, sizeof(tss), &tss);
if (skb->len && (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS))
put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING_OPT_STATS,
skb->len, skb->data);
}
}
EXPORT_SYMBOL_GPL(__sock_recv_timestamp);