[dtrace-discuss] fbt:ip:tcp_xchg:entry does not exists

[Brendan Gregg - Sun Microsystems]

G'Day Przemol,

On Thu, Jan 11, 2007 at 12:09:55PM +0100, przemolicc at poczta.fm wrote:
> Hello,
> 
> I am trying to use one of scripts from Dtrace toolkit and get:
> bash-3.00# dtrace -l|wc -l
>    47351
> bash-3.00# cat /etc/release 
>                         Solaris 10 6/06 s10x_u2wos_09a X86
>            Copyright 2006 Sun Microsystems, Inc.  All Rights Reserved.
>                         Use is subject to license terms.
>                              Assembled 09 June 2006
> bash-3.00# uname -a
> SunOS e2 5.10 Generic_118855-19 i86pc i386 i86pc
> bash-3.00# ./tcpsnoop.d
> dtrace: failed to compile script ./tcpsnoop.d: line 233: probe description fbt:ip:tcp_xchg:entry does not match any probes
> 
> Indeed, there is no such probe:
> bash-3.00# dtrace -l|wc -l
>    47351
> bash-3.00# dtrace -l|grep tcp_xchg

Sorry about this; While I hope that the tcpsnoop/tcptop scripts don't
break for Solaris updates, they are indeed the most fragile as they are
based on private unstable kernel implementation (fbt), as Jim said.
Ideally they would be based on a stable network provider, as Adam said,
but in the meantime it is either fbt or nothing.

This is also the reason I only wrote tcpsnoop/tcptop; I wanted (and still
want) to write numerous networking based scripts - but after writing
tcpsnoop.d it was obvious how fragile TCP tracing was. There is going
to be some real fun when we have a stable TCP provider.

I still don't know why tcp_xchg is missing - I can fix it, but first
I need to find out why it broke...

Brendan

-- 
Brendan
[CA, USA]