Re: HOWTO in wiki: adding custom dtrace probes in the kernel

On Sat, Nov 29, 2008 at 6:44 PM, Alexander Leidinger
<Alexander_at_leidinger.net> wrote:
> Quoting "Marius Nünnerich" <marius_at_nuenneri.ch> (Fri, 28 Nov 2008 19:47:21 +0100):
>
>> What is the intention of adding function entry and return providers
>> with SDT? Isn't that what FBT is for?
>
> To make it more easy for the dtrace script writter. If you want to
> trace all linuxulator specific stuff, you can use the wildcard
>  linuxulator:::entry { ... }
>
> Or if you want to trace everything specific to linux file related stuff
> you use the wildcard
>  linuxulator:file::entry { ... }
>
> With the fbt, this is much more difficult to do. You have to find out
> all related functions and specify them. This may not be hard for a
> kernel developer, but an user with a problem just wants to solve the
> problem, and getting an idea what is going on is more easy with the
> entry and return probes from the sdt, as they have a more narrow
> semantic meaning than the similar probe from the fbt (the fbt just
> tells you it's a kernel function, whereas the linuxulator probe
> provides you with the information that it is a function which belongs
> to the linuxulator and it's corresponding module grouping (like file
> related, ioctl related, ...)). No need to hunt down this info in the
> kernel yourself.

Many thanks for your explanation. That makes sense to me.