FYI, I finally got around to reproducing this, and I think I see what the
problem is.  Unfortunately I don't see a really trivial fix, but I've got
some ideas I'll work on to see if I can take care of it.

Steve

On Fri, Feb 18, 2011 at 5:21 AM, Steve Reinhardt <[email protected]> wrote:

> BTW, thanks for the detailed example... I've been traveling, but I'll see
> if I can reproduce this when I get home.
>
> Steve
>
> On Thu, Feb 17, 2011 at 11:21 AM, Richard Strong <[email protected]>wrote:
>
>> Here is the process I went through on a fresh checkout of m5 this morning.
>>
>> (1) hg clone http://repo.m5sim.org/m5
>>
>> (2) cd m5
>>
>> (3) scons build/ALPHA_SE/m5.opt
>>
>> (4) build/ALPHA_SE/m5.opt  configs/example/se.py  --take-checkpoint=1
>> --at-instruction
>>
>> (5) build/ALPHA_SE/m5.opt  configs/example/se.py  --checkpoint-restore=1
>> --at-instruction  -d --caches --l2cache
>> M5 Simulator System
>>
>> Copyright (c) 2001-2008
>> The Regents of The University of Michigan
>> All Rights Reserved
>>
>>
>> M5 compiled Feb 17 2011 09:41:58
>> M5 revision 96bde0910197+ 8031+ default tip
>> M5 started Feb 17 2011 09:54:32
>> M5 executing on rstrong-desktop
>> command line: build/ALPHA_SE/m5.opt configs/example/se.py
>> --checkpoint-restore=1 --at-instruction -d --caches --l2cache
>>
>> Global frequency set at 1000000000000 ticks per second
>> 0: system.remote_gdb.listener: listening for remote gdb #0 on port 7000
>> Switch at curTick count:10000
>> info: Entering event queue @ 1000.  Starting simulation...
>> panic: Tried to access unmapped address 0x12008b488.
>>  @ cycle 2500
>> [invoke:build/ALPHA_SE/arch/alpha/faults.cc, line 208]
>> Memory Usage: 586300 KBytes
>> For more information see: http://www.m5sim.org/panic/5932f339
>> Program aborted at cycle 2500
>> Aborted
>>
>> The problem seen in the output of (5) above is caused by the workload
>> being adopted by switch_cpus as its parent as opposed to system.cpu. My
>> original fix was to modify simulate.py  to adopt orphans in sorted order,
>> but this appears to create orphans for fuPool as shown in the snippet of
>> config.ini below. This makes me think that something is broken in the design
>> as it depends on the order in which objects come up if certain objects
>> become orphans or if checkpoint files work. Is there any way to explicitly
>> set the parent, child relationship if you want to avoid this non
>> determinism.
>>
>> config.ini selected output:
>> [system.switch_cpus.fuPool]
>> type=FUPool
>> FUList=(orphan) (orphan) (orphan) (orphan) (orphan) (orphan) (orphan)
>> (orphan) (orphan)
>>
>>
>>
>>
>>
>>
>> On Thu, Feb 17, 2011 at 5:45 AM, Steve Reinhardt <[email protected]>wrote:
>>
>>> Hi Rick,
>>>
>>> I'm a little confused by your statement "there is no recursion to add the
>>> children of params".  Being param value and being a child are separate
>>> things, because an object A can be a param of many other objects but can
>>> only be the child of one other object.  The only relationship between the
>>> two is that if A is set as a param value for a param of B and A does not
>>> have a parent, then A will also implicitly be set as a child of B.  (See
>>> towards the end of SimObject.__setattr__().)
>>>
>>> So every SimObject param value *should* be the child of *some* SimObject,
>>> so iterating over param values shouldn't be necessary.  The whole point of
>>> adoptOrphanParams() is to make sure this is true; it's the one place we
>>> iterate over all the param values, just to make sure that they all have
>>> parents (and to set them if they don't).
>>>
>>> Also, the adoptOrphanParams() method traverses the whole tree (see
>>> simulate.py) using the descendants() call which is a pre-order traversal, so
>>> any new children that are added at a particular node should be traversed
>>> automatically.
>>>
>>> Your configuration should not be affected by whether you're restoring
>>> from a checkpoint or not... the config gets built first, then if there's a
>>> checkpoint it gets restored.
>>>
>>> I rewrote all this code last summer to clean it up, so I'm very
>>> interested in figuring out where the bugs are.
>>>
>>> Steve
>>>
>>>
>>> On Wed, Feb 16, 2011 at 9:48 PM, Richard Strong <[email protected]>wrote:
>>>
>>>> I took a close look at this problem because the same thing happens to
>>>> me. It only occurs when I use the O3CPU model when resuming from a
>>>> checkpoint. What I find is that config.ini has orphan for the FUList
>>>> parameter of the O3CPU model. Further, none of the function units are
>>>> adopted by fuPool. I think the problem lies in 
>>>> SimObject.py::add_child(self,
>>>> name, child) and SimObject.py::
>>>> adoptOrphanParams(self). I think that there is no recursion to add the
>>>> children of params. I tried a simple change at the end of add_child, that I
>>>> adoptOrphanParams() of the child (change showed below). This allows the
>>>> setup code to get further but now I die with:
>>>>
>>>> "AttributeError: 'AnyProxy' object has no attribute 'getValue'. I was
>>>> wondering if someone knows what is going wrong? Did a recent change forget
>>>> to go down enough recursive levels when adopting children nodes?
>>>>
>>>> Best,
>>>> -Rick
>>>>
>>>> def add_child(self, name, child):
>>>>         print "\t in add_child name=%s child=%s"%(name, child)
>>>>         child = coerceSimObjectOrVector(child)
>>>>         if child.get_parent():
>>>>             raise RuntimeError, \
>>>>                   "add_child('%s'): child '%s' already has parent '%s'"
>>>> % \
>>>>                   (name, child._name, child._parent)
>>>>         if self._children.has_key(name):
>>>>             # This code path had an undiscovered bug that would make it
>>>> fail
>>>>             # at runtime. It had been here for a long time and was only
>>>>             # exposed by a buggy script. Changes here will probably not
>>>> be
>>>>             # exercised without specialized testing.
>>>>             self.clear_child(name)
>>>>         child.set_parent(self, name)
>>>>         self._children[name] = child
>>>>         if isSimObjectVector(child):
>>>>             for obj in child:
>>>>                 obj.adoptOrphanParams()
>>>>         elif isSimObjectOrVector(child):
>>>>             child.adoptOrphanParams()
>>>>
>>>>>
>>>>>
>>>>> On Fri, Feb 11, 2011 at 11:05 PM, Joel Hestness <
>>>>> [email protected]> wrote:
>>>>>
>>>>>> Hi Sheng,
>>>>>>   I've dug back through some of my simulations, and I haven't been
>>>>>> able to find a case where I used 4GB of simulated memory, so I don't 
>>>>>> know if
>>>>>> I have a baseline to show that the checkpoint restore works with that 
>>>>>> much
>>>>>> memory.  On the other hand, I have simulated with 512MB and 1GB of 
>>>>>> simulated
>>>>>> memory, and it has worked fine.  For full-system simulations, we often 
>>>>>> mount
>>>>>> a swap disk in the simulated system in order to avoid the small virtual
>>>>>> memory constraints imposed by the operating system.  I'd have to defer to
>>>>>> others on the list for knowledge about whether that would work with SE 
>>>>>> mode.
>>>>>>   I can attempt to address your other questions as well:
>>>>>>    1) The way that you described the O3 parameters is how I have set
>>>>>> them in the past, so that should work.
>>>>>>    2) I've seen this problem before... It has had to do with the way
>>>>>> that certain SimObjects are instantiated as children of other SimObjects 
>>>>>> at
>>>>>> the beginning of the simulation, and with checkpoint restore, this isn't 
>>>>>> the
>>>>>> cleanest process.  When I ran into this problem, I was working on getting
>>>>>> x86 timing mode working with Ruby, and Brad Beckmann was able to help me
>>>>>> debug.  He might be able to suggest first steps for figuring out what's
>>>>>> wrong here.
>>>>>>   Hope this helps,
>>>>>>   Joel
>>>>>>
>>>>>>
>>>>>> On Wed, Feb 9, 2011 at 3:14 PM, Sheng Li <[email protected]> wrote:
>>>>>>
>>>>>>> An two other questions:
>>>>>>>
>>>>>>> 1. What should I do to change the O3 parameters such as issueWidth,
>>>>>>> commitWidth, etc? I added a few lines in se.py as below. It runs fine 
>>>>>>> if I
>>>>>>> just run the benchmarks, but if I resume a checkpoint (created without 
>>>>>>> -d
>>>>>>> option), then it will complain the CPU class has no such parameters. I 
>>>>>>> think
>>>>>>> these parameters can only be set after M5 performs CPU mode switch, 
>>>>>>> then how
>>>>>>> can I set these parameters so that M5 will use them after switching CPU
>>>>>>> mode?
>>>>>>>
>>>>>>>  if options.detailed:
>>>>>>>     CPUClass.commitWidth    = 4
>>>>>>>     CPUClass.decodeWidth    = 4
>>>>>>>     CPUClass.dispatchWidth  = 4
>>>>>>>     CPUClass.fetchWidth     = 4
>>>>>>>     CPUClass.issueWidth     = 4
>>>>>>>     CPUClass.commitWidth    = 4
>>>>>>>     CPUClass.renameWidth    = 4
>>>>>>>     CPUClass.squashWidth    = 4
>>>>>>>     CPUClass.wbWidth        = 4
>>>>>>>     CPUClass.numROBEntries  = 128
>>>>>>>     CPUClass.numIQEntries   = 36
>>>>>>>     CPUClass.LQEntries      = 48
>>>>>>>
>>>>>>> 2. When I resume a checkpoint with -d --caches options, I got
>>>>>>> RuntimeError: Attempt to instantiate orphan node. I am trying to figure 
>>>>>>> out
>>>>>>> what the orphan node is. What should I do to find the orphan node? I 
>>>>>>> tried
>>>>>>> "print self.name" in File "/afs/
>>>>>>> crc.nd.edu/user/s/sli2/m5-stable/src/python/m5/SimObject.py", line
>>>>>>> 822, in getCCObject, but got nothing.
>>>>>>>
>>>>>>>
>>>>>>> command line: ./build/ALPHA_SE/m5.opt configs/example/se.py --bench
>>>>>>> bzip2 --checkpoint-restore=0 --simpoint -d --caches --l2cache
>>>>>>> 2200
>>>>>>> m5out/cpt.bzip2.2200
>>>>>>>
>>>>>>> Global frequency set at 1000000000000 ticks per second
>>>>>>>  Traceback (most recent call last):
>>>>>>>   File "<string>", line 1, in ?
>>>>>>>   File "/afs/crc.nd.edu/user/s/sli2/m5-stable/src/python/m5/main.py",
>>>>>>> line 359, in main
>>>>>>>     exec filecode in scope
>>>>>>>   File "configs/example/se.py", line 179, in ?
>>>>>>>     Simulation.run(options, root, system, FutureClass)
>>>>>>>   File "/afs/
>>>>>>> crc.nd.edu/user/s/sli2/m5-work-stable/configs/common/Simulation.py",
>>>>>>> line 236, in run
>>>>>>>     m5.instantiate(checkpoint_dir)
>>>>>>>   File "/afs/
>>>>>>> crc.nd.edu/user/s/sli2/m5-work-stable/src/python/m5/simulate.py",
>>>>>>> line 77, in instantiate
>>>>>>>     for obj in root.descendants(): obj.createCCObject()
>>>>>>>   File "/afs/
>>>>>>> crc.nd.edu/user/s/sli2/m5-stable/src/python/m5/SimObject.py", line
>>>>>>> 841, in createCCObject
>>>>>>>     def createCCObject(self):
>>>>>>>   File "/afs/
>>>>>>> crc.nd.edu/user/s/sli2/m5-stable/src/python/m5/SimObject.py", line
>>>>>>> 796, in getCCParams
>>>>>>>     value = value.getValue()
>>>>>>>   File "/afs/
>>>>>>> crc.nd.edu/user/s/sli2/m5-stable/src/python/m5/SimObject.py", line
>>>>>>> 845, in getValue
>>>>>>>     def getValue(self):
>>>>>>>   File "/afs/
>>>>>>> crc.nd.edu/user/s/sli2/m5-stable/src/python/m5/SimObject.py", line
>>>>>>> 826, in getCCObject
>>>>>>>     self._ccObject = -1
>>>>>>>   File "/afs/
>>>>>>> crc.nd.edu/user/s/sli2/m5-stable/src/python/m5/SimObject.py", line
>>>>>>> 796, in getCCParams
>>>>>>>     value = value.getValue()
>>>>>>>   File "/afs/
>>>>>>> crc.nd.edu/user/s/sli2/m5-stable/src/python/m5/params.py", line 183,
>>>>>>> in getValue
>>>>>>>     return [ v.getValue() for v in self ]
>>>>>>>   File "/afs/
>>>>>>> crc.nd.edu/user/s/sli2/m5-stable/src/python/m5/SimObject.py", line
>>>>>>> 845, in getValue
>>>>>>>     def getValue(self):
>>>>>>>   File "/afs/
>>>>>>> crc.nd.edu/user/s/sli2/m5-stable/src/python/m5/SimObject.py", line
>>>>>>> 822, in getCCObject
>>>>>>>     #print self.name
>>>>>>> RuntimeError: Attempt to instantiate orphan node
>>>>>>>
>>>>>>> Thanks a lot!
>>>>>>> -Sheng
>>>>>>>
>>>>>>
>>>
>>
>
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