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Re: GDB fast tracepoint query
- From: Suchakrapani Datt Sharma <suchakrapani dot sharma at polymtl dot ca>
- To: lgustavo at codesourcery dot com
- Cc: gdb at sourceware dot org
- Date: Wed, 01 May 2013 22:19:26 -0400
- Subject: Re: GDB fast tracepoint query
- References: <1367263644 dot 517ec99c4fb53 at www dot imp dot polymtl dot ca> <517ED307 dot 7000901 at codesourcery dot com>
Hi,
> AFAIU, the fast tracepoint jump pad will always be there if a trace
> experiment is running (with at least one active fast tracepoint set),
> which means GDB will take the path through the fast tracepoint's jump
> pad, save whatever needs to be saved, execute actions and then exit
> through the jump pad again. So there should be some small overhead there
> even if no actions are actually executed.
>
> As for the time when the instruction is modified, it is during the trace
> experiment startup, during "tstart". "ftrace" or "trace" will just
> register the tracepoint internally inside gdb.
>
> Luis
Thanks a lot for the info :) Sorry for the late reply
Suchakra
--
Suchakrapani Datt Sharma
Laboratorie DORSAL
École Polytechnique de Montréal