Date: Tue, 9 Mar 2010 07:47:00 -0500 From: John Baldwin <jhb@freebsd.org> To: Alexander Leidinger <Alexander@leidinger.net> Cc: freebsd-stable@freebsd.org, Robert Watson <rwatson@freebsd.org> Subject: Re: is dtrace usable? Message-ID: <201003090747.00192.jhb@freebsd.org> In-Reply-To: <20100309092709.16456y55vq0kaa88@webmail.leidinger.net> References: <E1Nnv0H-00020A-9M@kabab.cs.huji.ac.il> <201003081000.12656.jhb@freebsd.org> <20100309092709.16456y55vq0kaa88@webmail.leidinger.net>
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On Tuesday 09 March 2010 3:27:09 am Alexander Leidinger wrote: > Quoting John Baldwin <jhb@freebsd.org> (from Mon, 8 Mar 2010 10:00:12 -05= 00): >=20 > > 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= =2Ehtml > >> > > >> > 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=3Dyes > >> > to the kernel config instead of doing > >> > make WITH_CTF=3D1 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=3Dyes' 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? >=20 > I do not have a log around, it has been a while since I did something =20 > with dtrace (a year ago) and I can not remember that I always added =20 > WITH_CTF on a build (but it was about SDT probes, not FBT probes, in =20 > case it matters). >=20 > I had a look again, WITH_CTF=3Dyes is one of the first lines in the =20 > Makefile, and /usr/share/mk/sys.mk has "if !defined(WITH_CTF)". "make =20 > -V WITH_CTF" shows "yes", but "make -V NO_CTF" shows "1". This is =20 > strange, isn't it? I would expect that NO_CTF is undefined. Is this a =20 > bug in make, or a bug in the man page (neither in the description of =20 > the different kinds of variables, nor in the description of "defined" =20 > is something mentioned explaining this behavior). It is defined behavior. From the 2nd and 3rd paragraphs of the make(1) manual page: First of all, the initial list of specifications will be read from the system makefile, sys.mk, unless inhibited with the -r option. The sta= n- dard sys.mk as shipped with FreeBSD also handles make.conf(5), the default path to which can be altered via the make variable __MAKE_CONF. Then the first of BSDmakefile, makefile, and Makefile that can be found in the current directory, object directory (see .OBJDIR), or search pa= th (see the -I option) will be read for the main list of dependency speci= fi- cations. A different makefile or list of them can be supplied via the= -f option(s). Finally, if the file .depend can be found in any of the aforesaid locations, it will also be read (see mkdep(1)). =46rom this you can see that sys.mk is included and parsed before 'Makefile= ', so the WITH_CTF=3Dyes is not set until after sys.mk has been parsed. =2D-=20 John Baldwin
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