is dtrace usable?

[Alexander Leidinger]

Quoting John Baldwin <jhb at freebsd.org> (from Mon, 8 Mar 2010 10:00:12 -0500):

> On Saturday 06 March 2010 11:00:12 am Robert Watson wrote:
>> On Sat, 6 Mar 2010, Alexander Leidinger wrote:
>>
>> >> Take a look at the DTrace configuration information here:
>> >>
>> >>    http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/dtrace.html
>> >
>> > I've just reread it (despite the fact that I already used it). Some
>> > comments:
>> >
>> > Last time I tried, I didn't see any problems by adding
>> >  makeoptions     WITH_CTF=yes
>> > to the kernel config instead of doing
>> >  make WITH_CTF=1 kernel
>> >
>> > Did I miss something, and if not, shouldn't we tell about the
>> > makeoptions part instead (a kernel rebuild later will not cause
>> > trouble when someone forgets to do the WITH_CTF part as it is already
>> > in the kernel makefile)?
>>
>> I'll leave John to answer this one, CC line broadended.
>
> I would be very surprised if 'makeoptions WITH_CTF=yes' worked.  The many
> times I and others have tried it it did not work.  Do you have a log of your
> build showing the ctfconvert and ctfmerge command lines?

I do not have a log around, it has been a while since I did something  
with dtrace (a year ago) and I can not remember that I always added  
WITH_CTF on a build (but it was about SDT probes, not FBT probes, in  
case it matters).

I had a look again, WITH_CTF=yes is one of the first lines in the  
Makefile, and /usr/share/mk/sys.mk has "if !defined(WITH_CTF)". "make  
-V WITH_CTF" shows "yes", but "make -V NO_CTF" shows "1". This is  
strange, isn't it? I would expect that NO_CTF is undefined. Is this a  
bug in make, or a bug in the man page (neither in the description of  
the different kinds of variables, nor in the description of "defined"  
is something mentioned explaining this behavior).

The current kernel on my test machine is compiled with "makeoptions  
...", and a "dtrace -l" causes the watchdog to trigger a panic. Ugh...  
that's not a nice behavior. :(

Bye,
Alexander.

-- 
Adding sound to movies would be like
putting lipstick on the Venus de Milo.
		-- actress Mary Pickford, 1925

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