Re: [Simulavr-devel] Connect with gdb to a core of a python simulation

[ThomasK]

Hi Marek,

the consequence of having one "mother clock" for all is also, that 
multiple instances of gdb, every connected with a core, will not work. 
Who has the control over clock? And say "run" in one gdb instance, will 
also run in others?

To extend gdb server class to handle multiple cores - but just one core 
at time - isn't that problem. But then you need a command on gdb "switch 
to core X", and maybe some depending commands "how much cores", where am 
I" and so one. I'm not so familar with gdb - because I use it seldom - 
if there is any chance for that! Something of having custom commands and 
requests for gdb target.

All is connected with the master clock and it's control, but without 
this master clock, means different time-free running instances it makes 
no sense at all.

And sure, I think too, that this is seldom used. For the most cases it's 
enough to simulate "other" hardware, including an other avr controller. 
(and this is working really good, I had running amforth completely 
without real hardware - just running simulavr with extending serial IO 
in python and with a GUI to get output and give input)

cu, Thomas

Am 19.08.2011 21:59, schrieb Marek Pietrzak:
> Hi,
> First I'm not sure if debugging multiple cores is really something
> that's needed very often. If so, I think it's possible to see the cores
> in the simulation logically as separate threads in one and only instance
> of GDB. Here stopping one thread (core) would stop all other threads.
> It's the consequence of clock concept in simulavr (and called freeze
> mode debugging sometimes). Of course GdbServer class is not designed to
> do that, but if we ever wanted to support that...
>
> Marek
>
> On Thu, 2011-08-18 at 06:41 +0200, ThomasK wrote:
> > Hi guys,
> >
> > just to give my 2 cents ... ;-)
> >
> > I think, simulavr isn't able to fit to this plan with simulating 2 or
> > more avr cores in the same time (!) with gdb. I don't know, how to do
> > that with gdb - but that's not my topic. simulavr isn't designed to do that!
> >
> > How multicore works: it's one (!) process on OS, we have a instance of a
> > "mother clock" queue and, if needed, some instances of avr cores. This
> > is to synchronize the timing the hardware instances - and a core is
> > derived of hardware class. Gdb class shrinks into this "mother clock" to
> > serve also gdb requests. If you run 2 gdb server instances, you'll get a
> > dead lock. And on the other hand: if you debug simulavr with multicore
> > then you stop the time for all cores and all hardware instances! If
> > there is a request from gdb to change the core inside one (!)
> > connection, then it's possible. But maybe not that, what you want: to
> > see with 2 gdb instances how the code is processed in the same time on,
> > for example, two cores.
> >
> > So, extending simulavr.i will not help for this case, but maybe, if you
> > want to debug with gdb and to simulate some expected hardware around the
> > core with python. (for example, connect 2 pins from a port, connect a
> > external clock or such)
> >
> > Now you could tell: let's start 2 processes (threads), every with his
> > own gdb server. Then you have to fullfill some tasks: as written below,
> > if you debug in single step or halt the core, then you have to stop also
> > other cores - time synchronisation. Next: I'm not sure, if simulavr is
> > thread save now - that's sometimes difficult to solve but strong
> > neccessary! And you should have in mind: if you stop by gdb, you stop
> > too all, what's simulated in this thread!
> >
> > So, it's not impossible, but a lot of work from now! And then it's the
> > question: will this help you really for developing code? (for so much work)
> >
> > Ok, that's from me ... :-) cu, Thomas
> >
> >
> >
> > Am 15.08.2011 21:55, schrieb Sebastian:
> > > Hi,
> > > is it possible to connect with gdb to a core of a python simulation?
> > >
> > > Something like
> > >           device = pysimulavr.AvrFactory.instance().makeDevice(mcu)
> > >           device.Load(program)
> > >           device.SetClockFreq(clock_setting)
> > >           sim.Add(device)
> > >         device.setPortForGDB(1212) # I'm looking for this function
> > > which also works for simulations with multiple devices.
> > >
> > > Sebastian
> > >
> > >
> > >
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