Date: Sun, 30 May 2010 13:51:54 -0700 From: Artem Belevich <fbsdlist@src.cx> To: Shrikanth Kamath <shrikanth07@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: DTrace and CTF data Message-ID: <AANLkTilgGU-v4fQmwKMjevqoX2e8IOaCLz72ZJ_ZJm2f@mail.gmail.com> In-Reply-To: <AANLkTinuvZ_8onIF1O1Z42TiItqFDDUmng8PtWCnZQmm@mail.gmail.com> References: <AANLkTinuvZ_8onIF1O1Z42TiItqFDDUmng8PtWCnZQmm@mail.gmail.com>
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You may be confusing CTF info and the probes. Those are different things. CTF info just describes data types and variable/function location. DTrace later uses it to figure out where and how to install the probes. Probes are installed dynamically, at runtime when DTrace program is run. That's why you see it with kgdb on the live kernel once probe has been installed. DTrace does not modify your original kernel binary, so you will not see any probes there. --Artem On Sun, May 30, 2010 at 12:10 PM, Shrikanth Kamath <shrikanth07@gmail.com> wrote: > I have a query about the FBT provider in DTrace, does FBT provider not ne= ed > the CTF info for the /kernel binary... > > I have this observation, when I disassemble say a 'kernel_funtion' , I se= e > the function is not instrumented... > > (kgdb) disassemble kernel_function > Dump of assembler code for function kernel_function: > 0xc04aa05d <kernel_function+0>: push =A0 %ebp > 0xc04aa05e <kernel_function+1>: mov =A0 =A0%esp,%ebp > 0xc04aa060 <kernel_function+3>: sub =A0 =A0$0x2c,%esp > > > Now after I did a 'fbt::kernel_function:entry', if I disassemble the > 'kernel_function'... > > (kgdb) disassemble kernel_function > Dump of assembler code for function kernel_function: > 0xc04aa05d <kernel_function+0>: lock mov %esp,%ebp =A0 =A0 =A0 =A0 =A0 = =A0 =A0 =A0 <=3D=3D FBT > instrumentation > 0xc04aa060 <kernel_function+3>: sub =A0 =A0$0x2c,%esp > > If I do a 'objdump' on the kernel.debug binary I do not see any CTF secti= ons > showing up? > > > -- > Shrikanth R K > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org= " >
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