[PATCH 0 of 4] Add support for dtrace compatible sdt probes on GNU/Linux

[Mark Wielaard]

On Sun, 2012-07-22 at 08:10 +1000, David Holmes wrote:
> How portable is sys/sdt.h? Does it vary from linux to linux? What 
> happens if you build on linux A (as we do) and then run on linux B, C, D 
> ... ? What if it is not available at runtime? Will we get dynamic link 
> failures or ?

There is only one sys/sdt.h. The only code it "generates" is a NOP
instruction. For the rest it is like debug info, just an additional ELF
notes section with additional info on the binary (the only difference
being that this one is never stripped away). There is no runtime. There
are just tools like readelf, gdb, stap, that can interpret the extra
observability info in the ELF note section (and place breakpoints on the
NOP instructions if so instructed).

See also
http://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation

Cheers,

Mark