Current status of dtrace?

[Maledictus]

Hi all,

does anyone know where to get information about the current status of dtrace on FreeBSD? I'm especially interested in sdt/userland fbt. Maybe we could create a wiki page about it.

Kind regards
Maledictus

[RudiK]

There is a wiki entry already (http://wiki.freebsd.org/LiqunLi/DTrace_ToolKit), not very informative, perhaps we can get the author to add some updates.

[Maledictus]

Hmm, ok. That would be the way to go. Anyone has more info?

[trasz@]

As far as I know, right now DTrace supports kernel providers, but not userland ones.

[Maledictus]

Ok, thanks. Is jb@ working on adding more providers?

[rdivacky@]

Ok, thanks. Is jb@ working on adding more providers?

I guess jb@ might have some stuff in the queue but he's busy so he has not commited it yet. also, with the 7.1R fiasco (dtrace MFC 2 days before code freeze) I guess he's a bit hesitant to commit some more things :)

I wonder why dtrace is not on default in -current though

[nox@]

...
I wonder why dtrace is not on default in -current though

Maybe because (k)gdb doesnt understand it yet? I.e. with a dtrace-enabled kernel backtraces always look like there are no debug symbols even when there are...

[Maledictus]

Ah, that's a good explanation.

[rwatson@]

Some of these issues are being actively worked on in HEAD; in particular, there is a problem in which CTF generation appears not to be compatible with statically compiled binaries. I think there's room for other people who have time and interest to get involved here -- I've recently been looking at the set of kernel data providers and adding new SDT() probes is really quite straight forward. There's a FreeBSD.org wiki page on adding SDT() probes here:

http://wiki.freebsd.org/HOWTO-dtrace-sdt

It's worth checking Solaris or Mac OS X first to see if they have a set of probes similar to the ones you're adding so that we can make them as well-aligned as possible. That way tools, such as the DTrace toolkit, are as likely as possible to work across platforms as well. One issue I ran into yesterday is that our SYSINIT()-based SDT probe declaration doesn't permit '-' characters to be used in probe names, which was an issue for the callout probes I added:

http://lists.freebsd.org/pipermail/svn-src-head/2009-January/003096.html

[Graaf_van_Vlaanderen]

Any idea in which release it will be officially released as stable?

I tried it today, while running a heavy loading octave script and I received a kernel panic, while using 'hotkernel'.

[Maledictus]

Afaik there are no plans currently when to declare it stable.

[foo_daemon]

George V. Neville-Neil (I think) stated in a recent interview that userland Dtrace will happen in the '8.0 timeframe'. What that means, exactly, is left to the reader as an exercise.. ;)
citation @ 9:52 of
http://soekris.wtvl.k12.me.us/bsdtalk173.mp3