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

Steven Rostedt
2017-11-10T00:42:36Z

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