From: Pedro Alves <pedro@codesourcery.com>
To: gdb-patches@sourceware.org
Cc: Daniel Jacobowitz <dan@codesourcery.com>,
Joel Brobecker <brobecker@adacore.com>,
Maxim Grigoriev <maxim@tensilica.com>,
Marc Gauthier <marc@tensilica.com>,
Stan Shebs <stan@codesourcery.com>
Subject: Re: Faster stepping amidst breakpoints
Date: Tue, 01 Feb 2011 15:12:00 -0000 [thread overview]
Message-ID: <201102011512.24360.pedro@codesourcery.com> (raw)
In-Reply-To: <20110131151229.GA2915@caradoc.them.org>
On Tuesday 01 February 2011 15:12:35, Daniel Jacobowitz wrote:
> On Mon, Jan 31, 2011 at 08:49:51AM +0400, Joel Brobecker wrote:
> > > Consider "set breakpoint always-inserted".
> > > I've been wondering lately if we should flip the default.
> >
> > I like the idea of changing the default.
> >
> > Do you know what the risks would be? I looked at the code, and
> > there isn't something obvious/delicate, it seems. Perhaps we might
> > find ourselves forgetting to re-insert breakpoints, or inserting
> > them twice? I think you guys have more experience than we do?
>
> As far as I can remember (you know how much GDB development I do
> nowadays), the only risks were if GDB crashed and left the application
> with breakpoints inserted. Of course, I'm in favor of GDB not
> crashing.
>
> Pedro, Stan, any thoughts?
Regarding the OP's:
>Certain GDB operations involve a lot of single-stepping,
>which can be really slow on certain targets (especially
>embedded targets) because of that latency."
and the $subject:
> Faster stepping amidst breakpoints
... scenario, I'm not certain always-inserted alone helps that
much, because what always-inserted mainly affects, is whether
GDB removes breakpoints before giving the prompt to the
user, after the whole command finishes; and whether a
"break" or "delete" command inserts/removes breakpoints
in the target immediately. In all-stop mode, without
displaced stepping enabled, when stepping amidst
breakpoints, even with "breakpoint always-inserted on",
GDB _will still_ remove/insert all breakpoints to single-step
over a location that has a breakpoint.
It sounds to me that what you need to optimize that
use case, is to make GDB smarter into only
remove/inserting the breakpoint being stepped over,
instead of always remove/inserting _all_ breakpoints.
--
Pedro Alves
next prev parent reply other threads:[~2011-02-01 15:12 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-22 15:06 Maxim Grigoriev
2011-01-24 8:04 ` Daniel Jacobowitz
2011-01-24 21:08 ` Maxim Grigoriev
2011-01-31 7:47 ` Joel Brobecker
2011-01-31 15:39 ` Daniel Jacobowitz
2011-02-01 3:23 ` Joel Brobecker
2011-02-01 18:44 ` Michael Snyder
2011-02-03 4:55 ` Joel Brobecker
2011-02-02 17:10 ` Daniel Jacobowitz
2011-02-03 4:46 ` Joel Brobecker
2011-02-13 15:17 ` Mark Kettenis
2011-02-14 3:27 ` Joel Brobecker
2011-02-14 10:50 ` Joel Brobecker
2011-02-01 15:12 ` Pedro Alves [this message]
2011-02-03 22:54 ` Maxim Grigoriev
2011-02-04 16:06 ` Tom Tromey
2011-02-04 19:32 ` Maxim Grigoriev
2011-02-04 16:33 ` Daniel Jacobowitz
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