I see. I will look at that because it's weird that when I boot the disk it
complains about unhandled MMU.

On Sun, Mar 22, 2009 at 7:21 PM, Ali Saidi <[email protected]> wrote:

>
>
> It is changed when fault->invoke() is called. It then vectors to the
> OS which handles the fault and then calls retry(?) which rexecutes the
> instruction and away it goes.
>
> Ali
>
> On Mar 22, 2009, at 6:11 PM, Polina Dudnik wrote:
>
> > Ali,
> >
> > I traced the FastDataAccessMMUMiss and it seems that the fault
> > triggers advancePC function, which calls predecode.reset() and
> > that's about it. predecode.reset() doesn't seem to be doing anything
> > either. Shouldn't the PC be changed to the start of the handling
> > routine? Or am I missing something? Where is the
> > FastDataAccessMMUMiss actually handled?
> >
> > Polina
> >
> > On Sun, Mar 22, 2009 at 5:39 PM, Ali Saidi <[email protected]> wrote:
> > number of CPUs as I've defined them. If you wanted 8 contexts you
> > would pass -n 8
> >
> > Ali
> >
> > On Mar 22, 2009, at 5:09 PM, Polina Dudnik wrote:
> >
> > > So, when I pass -n 2, shouldn't there be 8 thread contexts: 4 for
> > > each processor? Or is -n 2 is the number of CPUs as you define them?
> > >
> > > On Sun, Mar 22, 2009 at 5:02 PM, Ali Saidi <[email protected]> wrote:
> > > The latter. The OS/hypervisor may believe that there are multiple
> > > threads on a CPU, but in reality there are actually multiple CPUs.
> > All
> > > the code I wrote for threads/cpus as far as the OS/hypervisor
> > layer is
> > > concerned assumed this (e.g. take the thread context ID % 4 to get
> > the
> > > CPU/thread id.
> > >
> > > Ali
> > >
> > > On Mar 22, 2009, at 2:47 PM, Polina Dudnik wrote:
> > >
> > > > So, you just don't allow multiple threads on a cpu or you
> > attempt to
> > > > flatten out multiple threads into multiple cpus?
> > > >
> > > > On Fri, Mar 20, 2009 at 5:31 PM, Steve Reinhardt
> > <[email protected]>
> > > > wrote:
> > > > By default, we do not simulate multithreading.  The SimpleCPU
> > models
> > > > are single-threaded.  The O3 model does have SMT capability, but
> > > it's
> > > > not enabled by default, and I'm not sure it's ever been used in FS
> > > > mode so there may well be bugs there.
> > > >
> > > > Steve
> > > >
> > > > 2009/3/20 Polina Dudnik <[email protected]>:
> > > > > Ali,
> > > > >
> > > > > Just to be clear: do or you do not simulate multithreading?
> > > > >
> > > > > There are two options that I can imagine:
> > > > >
> > > > > 1. When I pass -n 2 there are two multithreaded processors, each
> > > > of which
> > > > > has four thread contexts. In that case, seeing the ipi for
> > > > "cpu_id" 4 is
> > > > > completely right, because the ipi's come in for the threads, and
> > > > not cpu's.
> > > > > So, the simulator should not be getting confused about the ipi
> > for
> > > > 4.
> > > > >
> > > > >
> > > > > OR
> > > > >
> > > > > 2. You simulate each thread context as a processor. In that
> > case,
> > > > when I
> > > > > pass -n 2, there really should be 8 processors. In that case,
> > > > again ipi for
> > > > > 4 is entirely right.
> > > > >
> > > > > Which one is it?
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Polina
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > On Fri, Mar 20, 2009 at 2:54 PM, Polina Dudnik <[email protected]
> > >
> > > > wrote:
> > > > >>
> > > > >> Regarding running one processor with two threads, now that I
> > > > think about
> > > > >> it, OpenSparc definitely assigns thread numbers and not
> > processor
> > > > numbers in
> > > > >> hardware description file. Niagara does not have 32 processors,
> > > > but can have
> > > > >> 32 threads. So, by assigning thread numbers to be 0 and 4, it
> > > > ensures that
> > > > >> the threads are run on different processors. This is why the
> > > > number is 4. It
> > > > >> is the thread number.
> > > > >>
> > > > >> So I think those really are the cpu numbers as seen by the OS,
> > > > and they
> > > > >> have to be swizzled.
> > > > >>
> > > > >> Can you please tell me where you got the format for the ipi
> > > > message. So,
> > > > >> to be more clear in iob.cc:
> > > > >>
> > > > >>
> > > > >>             data = pkt->get<uint64_t>();
> > > > >>             type = (Type)bits(data,17,16);
> > > > >>             cpu_id = bits(data, 12,8);
> > > > >>             vector = bits(data,5,0);
> > > > >>             generateIpi(type,cpu_id, vector);
> > > > >>
> > > > >>
> > > > >> How do you know that cpu_id is at bits 5 through 0? I keep
> > > > looking through
> > > > >> OpenSparc documentation but can't find it.
> > > > >>
> > > > >>
> > > > >> Thanks.
> > > > >>
> > > > >> Polina
> > > > >>
> > > > >>
> > > > >> On Fri, Mar 20, 2009 at 1:26 PM, Polina Dudnik
> > > > <[email protected]> wrote:
> > > > >>>
> > > > >>>
> > > > >>> On Fri, Mar 20, 2009 at 1:11 PM, Ali Saidi <[email protected]>
> > > > wrote:
> > > > >>>>
> > > > >>>> Yea, that makes sense. You should probably look at the TLBs
> > > > (that is
> > > > >>>> where a lot of the miscellaneous system registers live). The
> > > > confusion
> > > > >>>> probably comes from reading one of those and the ids not
> > being
> > > > >>>> swizzeled, or perhaps there is an interrupt message with a
> > CPU
> > > > id or
> > > > >>>> something as well.
> > > > >>>
> > > > >>>
> > > > >>> Right, that's what I was thinking. I will look at the TLB's
> > and
> > > > the
> > > > >>> interrupt. Perhaps you can help me with a more specific
> > > > question: when I
> > > > >>> post an interrupt, I basically write a bit in the interrupt
> > > > array. How does
> > > > >>> the hypervisor find out about it? Who reads the interrupt
> > array?
> > > > >>>
> > > > >>>>
> > > > >>>>
> > > > >>>> I guess your attempts at convincing the hypervisor that the
> > > > next cpu
> > > > >>>> was #1 failed?
> > > > >>>
> > > > >>> It is not even that. According to David Wood, it might not be
> > > > the best
> > > > >>> idea to change cpu numbers because there are a lot of things
> > > > that determine
> > > > >>> the cpu numbers. So, I think the reason that changing the
> > > hardware
> > > > >>> description files did not have any effect is because the
> > > > description files
> > > > >>> are fitted to the hypervisor and not the other way around. I
> > am
> > > > right now
> > > > >>> trying to find where the hardware description binary is used
> > if
> > > > ever.
> > > > >>>
> > > > >>>
> > > > >>>>
> > > > >>>> What about calling the next CPU thread 1 (e.g. make a
> > > > >>>> system with 2 threads and 1 core)?
> > > > >>>
> > > > >>> Yes, I remember I was supposed to do that. Sorry for the
> > delay,
> > > > I will
> > > > >>> certainly try that. Currently I am trying to run 32 processors
> > > > because at
> > > > >>> least they are ordered and shouldn't require swizzling, so
> > we'll
> > > > see what
> > > > >>> happens.
> > > > >>>
> > > > >>>
> > > > >>>>
> > > > >>>> Ali
> > > > >>>>
> > > > >>>>
> > > > >>>>
> > > > >>>> On Mar 20, 2009, at 12:52 PM, Polina Dudnik wrote:
> > > > >>>>
> > > > >>>> > Right, I wasn't going to modify the hypervisor. But
> > swizzling
> > > > the
> > > > >>>> > numbers clearly affects the hypervisor because when
> > > > hypervisor sends
> > > > >>>> > messages, the processor number is swizzled from 4 to 1. So,
> > > > >>>> > initially the hypervisor thinks that there are cpu #0 and
> > #4,
> > > > but
> > > > >>>> > then it probably receives some messages or whatever, which
> > > > have cpu
> > > > >>>> > #1. So, I think the reason that the hypervisor reports that
> > > > cpu1
> > > > >>>> > failed to start is due to the confusion over the cpu
> > numbers.
> > > > Does
> > > > >>>> > this make sense?
> > > > >>>> >
> > > > >>>> > So, if m5 shall use cou #0 and #1 internally, it should
> > make
> > > > sure
> > > > >>>> > that all the external messages are suited for the binaries
> > > form
> > > > >>>> > OpenSparc.
> > > > >>>> >
> > > > >>>> > Polin
> > > > >>>> >
> > > > >>>> > On Fri, Mar 20, 2009 at 12:02 PM, Ali Saidi <[email protected]
> > >
> > > > wrote:
> > > > >>>> > The changes should only affect the portions of the system
> > > > that the
> > > > >>>> > hypervisor is calling. There shouldn't be any changes
> > > > required within
> > > > >>>> > the hypervisor code.
> > > > >>>> >
> > > > >>>> > Ali
> > > > >>>> >
> > > > >>>> > On Mar 19, 2009, at 1:22 PM, Polina Dudnik wrote:
> > > > >>>> >
> > > > >>>> > > Hi,
> > > > >>>> > >
> > > > >>>> > > So, to make sparc_fs work Ali and later I swizzled the
> > > > processor
> > > > >>>> > > numbers from 4 to 1 because m5 expects 1 and gets 4. In
> > > > order to
> > > > >>>> > > make this hack work, we also need to swizzle the numbers
> > > > back before
> > > > >>>> > > calling the hypervisor. So, the processor numbers going
> > > > into the
> > > > >>>> > > hypervisor should be swizzled back. So, in effect there
> > > > should be a
> > > > >>>> > > map which enables translation both ways. Does anyone know
> > > > where I
> > > > >>>> > > can start looking for calls to the hypervisor? Thank you.
> > > > >>>> > >
> > > > >>>> > > Polina
> > > > >>>> > >
> > > > >>>> > >
> > > > >>>> > > _______________________________________________
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