Re: [RFA/testsuite] attach.exp: Add small delay in busy loop...

[Daniel Jacobowitz <drow at mvista dot com>]

On Wed, Nov 19, 2003 at 11:15:55AM -0800, Michael Snyder wrote:
> Daniel Jacobowitz wrote:
> >On Tue, Nov 18, 2003 at 04:26:07PM -0800, Michael Snyder wrote:
> >
> >>Joel Brobecker wrote:
> >>
> >>>Hello,
> >>>
> >>>The attach.exp sometimes fails on certain platforms (eg mips-irix),
> >>>and causes an attach process to be left behind. Since it is doing a busy
> >>>loop, this runaway process left behind consumes 99.9% of the CPU,
> >>>and considerably slows down the execution of the rest of the testsuite.
> >>>
> >>>I suggest the following change to add a small delay at each iteration
> >>>of the busy loop. I had to make some adjustments to attach.exp:
> >>>
> >>>a. Line number 19 became line 32.
> >>>   Just like Elena recently upgraded a test to avoid hard-coded
> >>>   line number, we should probably clean this up, someday. This can
> >>>   be a separate patch, however.
> >>>
> >>>b. The program was attached to while inside the busy loop, so the
> >>>   test was expecting the debugger to report that the inferior was
> >>>   inside function main() after the attach command was performed.
> >>>   This is no longer the case, since the inferior is most likely
> >>>   inside a system call, doing the delay. I felt that it was not
> >>>   a necessity to checke where the debugger thought the inferior
> >>>   was stopped, so removed that part of the expected output. What
> >>>   I can do is add an extra test that does a backtrace and verifies
> >>>   that it contains a frame for function main().
> >>>
> >>>2003-11-18  J. Brobecker  <brobecker@gnat.com>
> >>>
> >>>      * gdb.base/attach.c: Add small delay in busy loop.
> >>>      * gdb.base/attach.exp: Make some associated adjustments.
> >>>
> >>>OK to apply?
> >>
> >>Seems to work on Linux.  I'd sure like to see that backtrace test,
> >>though, to confirm that we are able to build a meaningful machine
> >>state after we attach.
> >
> >
> >Seems reasonable to me.  Warning: this will be yet another place we
> >backtrace from syscalls, and sometimes we just can't do that.  We
> >already have a couple of configurations where GDB can't reasonably be
> >expected to backtrace out of nanosleep.
> 
> Well, we could run to a known breakpoint and then backtrace --
> but that wouldn't test the state immediately after attach.
> Can you think of a good test for a valid state, other than
> a backtrace?

Not really.  Let's not worry about the problem for now.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer