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Re: [RFC] Observer mode
- From: Stan Shebs <stan at codesourcery dot com>
- To: Michael Snyder <msnyder at vmware dot com>
- Cc: Stan Shebs <stan at codesourcery dot com>, "gdb-patches at sourceware dot org" <gdb-patches at sourceware dot org>
- Date: Thu, 29 Apr 2010 20:19:16 -0700
- Subject: Re: [RFC] Observer mode
- References: <4BD9C057.9090805@codesourcery.com> <4BD9CC1D.9040104@vmware.com>
Michael Snyder wrote:
Stan Shebs wrote:
Here is another patch that pushes the envelope a bit, and for which I
would like to get some prior agreement that it's a good idea.
The basic idea here is that GDB is to be used to look at targets
installed in the field and in use. In such a situation it may
connect to the target and examine state, but not alter that state or
interrupt anything. In our particular target, tracing is allowed,
but only using fast tracepoints, because they are done using jumps
and thus act as if they were part of the program; taking a trap, even
for a slow tracepoint, disrupts thread execution unacceptably. We
have been calling this "observer mode", and the customer's GDB is
actually configured to launch in this mode, to reduce the chance of
accidental stopping - the debugger user has to ask specifically to
change it to normal debugging mode.
[...]
How different is this from async mode?
Observer mode includes async mode. One could call it a "read-only
non-stop async mode that allows fast tracepoints", although that's
rather a mouthful. :-)
Stan