Re: [PATCH] net/tcp: introduce TRACE_EVENT for TCP/IPv4 state transition

[Steven Rostedt <rostedt@goodmis.org>]

On Thu, 9 Nov 2017 23:40:13 +0000
Song Liu <songliubraving@fb.com> wrote:

> > tcp_set_state uses __print_symbolic to show state in text format. I found
> > trace-cmd cannot parse that part:
> > 
> > [011] 147338.660560: tcp_set_state:        sport=16262 dport=48346 \
> >    saddr=127.0.0.6 daddr=127.0.0.6 saddrv6=2401:db00:30:317e:face:0:1f:0 \
> >    daddrv6=2401:db00:30:31e5:face:0:7f:0 oldstate= newstate=

The latest trace-cmd does show oldstate=0xa newstate=0x7, since I fixed
it so undefined symbols and flags are displayed.

> > 
> > Other parts of the output looks good to me.
> > 
> > Thanks,
> > Song  
> 
> I am not sure whether this is the best approach, but the following patch 
> fixes the output of perf:

No it's not the best approach. But the below patch is ;-)

> 
>      0.44%  sport=16262 dport=39362 saddr=127.0.0.6 daddr=127.0.0.6 \
> saddrv6=2401:db00:30:317e:face:0:1f:0 daddrv6=2401:db00:30:31e5:face:0:7f:0 \
> oldstate=TCP_CLOSE_WAIT newstate=TCP_LAST_ACK
> 

I'll send a formal patch if you all approve.

-- Steve

diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h
index 07cccca6cbf1..62e5bad7901f 100644
--- a/include/trace/events/tcp.h
+++ b/include/trace/events/tcp.h
@@ -9,21 +9,36 @@
 #include <linux/tracepoint.h>
 #include <net/ipv6.h>
 
+#define tcp_state_names				\
+	EM(TCP_ESTABLISHED)			\
+	EM(TCP_SYN_SENT)			\
+	EM(TCP_SYN_RECV)			\
+	EM(TCP_FIN_WAIT1)			\
+	EM(TCP_FIN_WAIT2)			\
+	EM(TCP_TIME_WAIT)			\
+	EM(TCP_CLOSE)				\
+	EM(TCP_CLOSE_WAIT)			\
+	EM(TCP_LAST_ACK)			\
+	EM(TCP_LISTEN)				\
+	EM(TCP_CLOSING)				\
+	EMe(TCP_NEW_SYN_RECV)
+
+/* enums need to be exported to user space */
+#undef EM
+#undef EMe
+#define EM(a)         TRACE_DEFINE_ENUM(a);
+#define EMe(a)        TRACE_DEFINE_ENUM(a);
+
+tcp_state_names
+
+#undef EM
+#undef EMe
+#define EM(a)         tcp_state_name(a),
+#define EMe(a)        tcp_state_name(a)
+
 #define tcp_state_name(state)	{ state, #state }
 #define show_tcp_state_name(val)			\
-	__print_symbolic(val,				\
-		tcp_state_name(TCP_ESTABLISHED),	\
-		tcp_state_name(TCP_SYN_SENT),		\
-		tcp_state_name(TCP_SYN_RECV),		\
-		tcp_state_name(TCP_FIN_WAIT1),		\
-		tcp_state_name(TCP_FIN_WAIT2),		\
-		tcp_state_name(TCP_TIME_WAIT),		\
-		tcp_state_name(TCP_CLOSE),		\
-		tcp_state_name(TCP_CLOSE_WAIT),		\
-		tcp_state_name(TCP_LAST_ACK),		\
-		tcp_state_name(TCP_LISTEN),		\
-		tcp_state_name(TCP_CLOSING),		\
-		tcp_state_name(TCP_NEW_SYN_RECV))
+	__print_symbolic(val, tcp_state_names)
 
 /*
  * tcp event with arguments sk and skb