2022-04-06 14:23:12

by Ping Gan

[permalink] [raw]
Subject: [PATCH net-next] tcp: Add tracepoint for tcp_set_ca_state

From: Ping Gan <[email protected]>

The congestion status of a tcp flow may be updated since there
is congestion between tcp sender and receiver. It makes sense to
add tracepoint for congestion status set function to summate cc
status duration and evaluate the performance of network
and congestion algorithm. the backgound of this patch is below.

Link: https://github.com/iovisor/bcc/pull/3899

Signed-off-by: Ping Gan <[email protected]>
---
include/net/tcp.h | 12 +++---------
include/trace/events/tcp.h | 45 +++++++++++++++++++++++++++++++++++++++++++++
net/ipv4/tcp_cong.c | 12 ++++++++++++
3 files changed, 60 insertions(+), 9 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 70ca4a5e330a..9a3786f33798 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1139,15 +1139,6 @@ static inline bool tcp_ca_needs_ecn(const struct sock *sk)
return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN;
}

-static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
-{
- struct inet_connection_sock *icsk = inet_csk(sk);
-
- if (icsk->icsk_ca_ops->set_state)
- icsk->icsk_ca_ops->set_state(sk, ca_state);
- icsk->icsk_ca_state = ca_state;
-}
-
static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
@@ -1156,6 +1147,9 @@ static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
icsk->icsk_ca_ops->cwnd_event(sk, event);
}

+/* From tcp_cong.c */
+void tcp_set_ca_state(struct sock *sk, const u8 ca_state);
+
/* From tcp_rate.c */
void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb);
void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb,
diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h
index 521059d8dc0a..69a68b01c1de 100644
--- a/include/trace/events/tcp.h
+++ b/include/trace/events/tcp.h
@@ -371,6 +371,51 @@ DEFINE_EVENT(tcp_event_skb, tcp_bad_csum,
TP_ARGS(skb)
);

+TRACE_EVENT(tcp_cong_state_set,
+
+ TP_PROTO(struct sock *sk, const u8 ca_state),
+
+ TP_ARGS(sk, ca_state),
+
+ TP_STRUCT__entry(
+ __field(const void *, skaddr)
+ __field(__u16, sport)
+ __field(__u16, dport)
+ __array(__u8, saddr, 4)
+ __array(__u8, daddr, 4)
+ __array(__u8, saddr_v6, 16)
+ __array(__u8, daddr_v6, 16)
+ __field(__u8, cong_state)
+ ),
+
+ TP_fast_assign(
+ struct inet_sock *inet = inet_sk(sk);
+ __be32 *p32;
+
+ __entry->skaddr = sk;
+
+ __entry->sport = ntohs(inet->inet_sport);
+ __entry->dport = ntohs(inet->inet_dport);
+
+ p32 = (__be32 *) __entry->saddr;
+ *p32 = inet->inet_saddr;
+
+ p32 = (__be32 *) __entry->daddr;
+ *p32 = inet->inet_daddr;
+
+ TP_STORE_ADDRS(__entry, inet->inet_saddr, inet->inet_daddr,
+ sk->sk_v6_rcv_saddr, sk->sk_v6_daddr);
+
+ __entry->cong_state = ca_state;
+ ),
+
+ TP_printk("sport=%hu dport=%hu saddr=%pI4 daddr=%pI4 saddrv6=%pI6c daddrv6=%pI6c cong_state=%u",
+ __entry->sport, __entry->dport,
+ __entry->saddr, __entry->daddr,
+ __entry->saddr_v6, __entry->daddr_v6,
+ __entry->cong_state)
+);
+
#endif /* _TRACE_TCP_H */

/* This part must be outside protection */
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index dc95572163df..98b48bdb8be7 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -16,6 +16,7 @@
#include <linux/gfp.h>
#include <linux/jhash.h>
#include <net/tcp.h>
+#include <trace/events/tcp.h>

static DEFINE_SPINLOCK(tcp_cong_list_lock);
static LIST_HEAD(tcp_cong_list);
@@ -33,6 +34,17 @@ struct tcp_congestion_ops *tcp_ca_find(const char *name)
return NULL;
}

+void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ trace_tcp_cong_state_set(sk, ca_state);
+
+ if (icsk->icsk_ca_ops->set_state)
+ icsk->icsk_ca_ops->set_state(sk, ca_state);
+ icsk->icsk_ca_state = ca_state;
+}
+
/* Must be called with rcu lock held */
static struct tcp_congestion_ops *tcp_ca_find_autoload(struct net *net,
const char *name)
--
2.15.0


2022-04-07 13:18:22

by Eric Dumazet

[permalink] [raw]
Subject: Re: [PATCH net-next] tcp: Add tracepoint for tcp_set_ca_state

On Tue, Apr 5, 2022 at 6:12 PM jackygam2001 <[email protected]> wrote:
>
> From: Ping Gan <[email protected]>
>
> The congestion status of a tcp flow may be updated since there
> is congestion between tcp sender and receiver. It makes sense to
> add tracepoint for congestion status set function to summate cc
> status duration and evaluate the performance of network
> and congestion algorithm. the backgound of this patch is below.
>
> Link: https://github.com/iovisor/bcc/pull/3899
>
> Signed-off-by: Ping Gan <[email protected]>
> ---

This seems good to me, thanks.

Reviewed-by: Eric Dumazet <[email protected]>

2022-04-08 01:27:45

by Ping Gan

[permalink] [raw]
Subject: Re: [PATCH net-next] tcp: Add tracepoint for tcp_set_ca_state

At 2022-04-07 14:05:42, "Eric Dumazet" <[email protected]> wrote:
> On Tue, Apr 5, 2022 at 6:12 PM jackygam2001 <[email protected]> wrote:
> >
> > From: Ping Gan <[email protected]>
> >
> > The congestion status of a tcp flow may be updated since there
> > is congestion between tcp sender and receiver. It makes sense to
> > add tracepoint for congestion status set function to summate cc
> > status duration and evaluate the performance of network
> > and congestion algorithm. the backgound of this patch is below.
> >
> > Link: https://github.com/iovisor/bcc/pull/3899
> >
> > Signed-off-by: Ping Gan <[email protected]>
> > ---
>
> This seems good to me, thanks.
>
> Reviewed-by: Eric Dumazet <[email protected]>
Thanks for you comment and review!


2022-04-08 04:35:33

by patchwork-bot+netdevbpf

[permalink] [raw]
Subject: Re: [PATCH net-next] tcp: Add tracepoint for tcp_set_ca_state

Hello:

This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <[email protected]>:

On Wed, 6 Apr 2022 09:09:56 +0800 you wrote:
> From: Ping Gan <[email protected]>
>
> The congestion status of a tcp flow may be updated since there
> is congestion between tcp sender and receiver. It makes sense to
> add tracepoint for congestion status set function to summate cc
> status duration and evaluate the performance of network
> and congestion algorithm. the backgound of this patch is below.
>
> [...]

Here is the summary with links:
- [net-next] tcp: Add tracepoint for tcp_set_ca_state
https://git.kernel.org/netdev/net-next/c/15fcdf6ae116

You are awesome, thank you!
--
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