Re: user instruction tracing patch?

["Frank Ch. Eigler" <fche@redhat.com>]

Hi, Dave -

> I am finally at a point where I can start looking at the translator 
> changes to support instruction tracing.  [...]

> >  probe process(PID).itrace { }
> >  probe process(PID).btrace { }   # block trace

This is the only variant you need to worry about, as

> >  probe process(NAME).itrace { }
> >  probe process(NAME).btrace { }

this stuff will come later, based on process-lifetime-tracking code
being currently built by dsmith.


> [...]
> These probes simply establish that instruction tracing, either itrace, 
> or btrace, is requested for specific processes, and associating a 
> generated handler corresponding to the { ... } part.
> 
> >Since utrace will provide the pt_regs structure, the probe handler
> >bodies will be able to call e.g. backtrace(), probefunc(), and really
> >should have some structured access to the registers (a new tapset
> >function like register:long ("name") ?)

The tapset extensions for context access are very similar to the needs
of symbol-only probing being worked on jkenisto.


> >  probe process(PID).itrace if (condition) { }
> >  probe process(PID).function("NAME") { condition = 1 }
> >  probe process(PID).function("NAME").return { condition = 0 }

This part will already work.


 FChE