Re: [PATCH v3] sock: add tracepoint for send recv length
From: Cong Wang <hidden>
Date: 2023-01-07 20:03:05
Also in:
linux-trace-kernel, lkml
On Sat, Jan 07, 2023 at 11:59:23AM +0800, Yunhui Cui wrote:
Add 2 tracepoints to monitor the tcp/udp traffic of per process and per cgroup. Regarding monitoring the tcp/udp traffic of each process, there are two existing solutions, the first one is https://www.atoptool.nl/netatop.php. The second is via kprobe/kretprobe. Netatop solution is implemented by registering the hook function at the hook point provided by the netfilter framework. These hook functions may be in the soft interrupt context and cannot directly obtain the pid. Some data structures are added to bind packets and processes. For example, struct taskinfobucket, struct taskinfo ... Every time the process sends and receives packets it needs multiple hashmaps,resulting in low performance and it has the problem fo inaccurate tcp/udp traffic statistics(for example: multiple threads share sockets). We can obtain the information with kretprobe, but as we know, kprobe gets the result by trappig in an exception, which loses performance compared to tracepoint. We compared the performance of tracepoints with the above two methods, and the results are as follows: ab -n 1000000 -c 1000 -r http://127.0.0.1/index.html without trace: Time per request: 39.660 [ms] (mean) Time per request: 0.040 [ms] (mean, across all concurrent requests) netatop: Time per request: 50.717 [ms] (mean) Time per request: 0.051 [ms] (mean, across all concurrent requests) kr: Time per request: 43.168 [ms] (mean) Time per request: 0.043 [ms] (mean, across all concurrent requests) tracepoint: Time per request: 41.004 [ms] (mean) Time per request: 0.041 [ms] (mean, across all concurrent requests It can be seen that tracepoint has better performance. Signed-off-by: Yunhui Cui <redacted> Signed-off-by: Xiongchun Duan <redacted>
Thanks for the numbers, they help a lot. Acked-by: Cong Wang <redacted> A few minor issues below.
quoted hunk ↗ jump to hunk
--- include/trace/events/sock.h | 49 +++++++++++++++++++++++++++++++++++++ net/socket.c | 20 +++++++++++++-- 2 files changed, 67 insertions(+), 2 deletions(-)diff --git a/include/trace/events/sock.h b/include/trace/events/sock.h index 777ee6cbe933..16092c0406a2 100644 --- a/include/trace/events/sock.h +++ b/include/trace/events/sock.h@@ -263,6 +263,55 @@ TRACE_EVENT(inet_sk_error_report, __entry->error) ); +/* + * sock send/recv msg length + */ +DECLARE_EVENT_CLASS(sock_msg_length, + + TP_PROTO(struct sock *sk, __u16 family, __u16 protocol, int ret, + int flags), + + TP_ARGS(sk, family, protocol, ret, flags), + + TP_STRUCT__entry( + __field(void *, sk) + __field(__u16, family) + __field(__u16, protocol) + __field(int, length) + __field(int, error) + __field(int, flags) + ), + + TP_fast_assign( + __entry->sk = sk; + __entry->family = sk->sk_family; + __entry->protocol = sk->sk_protocol; + __entry->length = ret > 0 ? ret : 0; + __entry->error = ret < 0 ? ret : 0; + __entry->flags = flags; + ), + + TP_printk("sk address = %p, family = %s protocol = %s, length = %d, error = %d, flags = 0x%x", + __entry->sk, + show_family_name(__entry->family), + show_inet_protocol_name(__entry->protocol), + __entry->length, + __entry->error, __entry->flags)
Please align and pack those parameters properly.
+); + +DEFINE_EVENT(sock_msg_length, sock_sendmsg_length, + TP_PROTO(struct sock *sk, __u16 family, __u16 protocol, int ret, + int flags), + + TP_ARGS(sk, family, protocol, ret, flags) +); + +DEFINE_EVENT(sock_msg_length, sock_recvmsg_length, + TP_PROTO(struct sock *sk, __u16 family, __u16 protocol, int ret, + int flags), + + TP_ARGS(sk, family, protocol, ret, flags) +);
It might be a better idea to remove "msg" from the tracepoint names, in case of any confusion with "sendpage". So s/sock_sendmsg_length/sock_send_length/ ?
quoted hunk ↗ jump to hunk
#endif /* _TRACE_SOCK_H */ /* This part must be outside protection */diff --git a/net/socket.c b/net/socket.c index 888cd618a968..37578e8c685b 100644 --- a/net/socket.c +++ b/net/socket.c@@ -106,6 +106,7 @@ #include <net/busy_poll.h> #include <linux/errqueue.h> #include <linux/ptp_clock_kernel.h> +#include <trace/events/sock.h> #ifdef CONFIG_NET_RX_BUSY_POLL unsigned int sysctl_net_busy_read __read_mostly;@@ -715,6 +716,9 @@ static inline int sock_sendmsg_nosec(struct socket *sock, struct msghdr *msg) inet_sendmsg, sock, msg, msg_data_left(msg)); BUG_ON(ret == -EIOCBQUEUED); + + trace_sock_sendmsg_length(sock->sk, sock->sk->sk_family, + sock->sk->sk_protocol, ret, 0); return ret; }@@ -992,9 +996,16 @@ INDIRECT_CALLABLE_DECLARE(int inet6_recvmsg(struct socket *, struct msghdr *, static inline int sock_recvmsg_nosec(struct socket *sock, struct msghdr *msg, int flags) { - return INDIRECT_CALL_INET(sock->ops->recvmsg, inet6_recvmsg, + int ret = INDIRECT_CALL_INET(sock->ops->recvmsg, inet6_recvmsg, inet_recvmsg, sock, msg, msg_data_left(msg), flags);
Please adjust the indentations properly. Thanks.