Re: about QTro packet (tracepoints)

[Jim Blandy <jimb@redhat.com>]

ankit thukral <ankit_plug@yahoo.com> writes:

>  hi all,
>         i was reading the packets' format in GDB for
>  tracepoints (like QTStart,QTinit etc.) and came
>  across
>  "QTro" packet format.i learned that this packet
>  transmits the addresses of all the LOADABLE
>  READ-ONLY
>  sections to the remote stub so that the latter can
>  always entertain a request for data belonging to
>  these
>  address ranges,even if this was not specified as a
>  tracepoint action by the user.
>        would it not be a better option to let the
>  remote stub collect this information of it's own
>  (from
>  it's own copy of the executable) rather than GDB
>  transmitting it across the network which definitely
>  is
>  more costly in terms of time delay suffered by the
>  process which becomes all the more costly while
>  debugging a real-time application?

If you're running Linux or something like that on the target, sure.
But tracepoints also need to work on systems with no operating system
at all, just a stub.  In that case, the stub has no idea which
sections are read-only and which sections may change.

The QTro packet is only sent once, when the trace experiment begins;
is it actually a major time sink?  How many sections do you have?