Re: [Gems-users] Fatal Error: Simics get unstalled without ruby

["Mark Gebhart" <mgebhart@xxxxxxxxxxxxx>]

Kevin,

Thanks for the advice, binding each thread to its own processor seems to
have gotten rid of the problem I was having.

Thanks,
Mark

-----Original Message-----
From: gems-users-bounces@xxxxxxxxxxx [mailto:gems-users-bounces@xxxxxxxxxxx]
On Behalf Of Kevin Moore
Sent: Monday, December 11, 2006 2:49 PM
To: Gems Users
Subject: Re: [Gems-users] Fatal Error: Simics get unstalled without ruby

Mark,
	When I see this error running LogTM programs, the cause is 
usually that one thread has been swapped out in the middle 
of a transaction.  To see if this is the case in your  run, 
set PROFILE_XACT and PROFILE_EXCEPTIONS to true.  Look to 
see if one or more transactions are being nacked by a 
processor that is not making any transactional loads or 
stores, or only making transactional loads/stores in 
exceptions.  If that's the case, your transaction has likely 
been swapped out.
	The current (released) version of LogTM has a simple, fixed 
conflict resolution policy that favors older transactions 
and does not take special action when a thread is swapped 
out.  Although we're working to develop a more robust 
mechanism for resolving conflicts, this case usually is a 
sign that an error has occurred.  I recommend binding 
threads to processors to prevent the OS from shuffuling 
threads and installing signal handlers to catch segmentation 
faults and bus errors, since waiting for a core dump can 
take a very long time in simulation.  Good luck,

Kevin

Dan Gibson wrote:
> That error will arise if Ruby stalls a processor and never delivers a 
> hit callback:
> To stall a processor "indefinately," Ruby stalls it for a large number 
> of cycles (I think 2,000,000, but it could be 2,000,000,000). 
> Eventually, if Ruby fails to unstall a processor, the 2e6 cycles elapses 
> and Simics resumes execution-- ergo "Simics get(s) unstalled without 
> Ruby asking".
> 
> I have no idea how this might arise in the LogTM code...
> 
> Regards,
> Dan
> 
> Mark Gebhart wrote:
> 
>> Hi,
>>
>> Sorry for a duplicate question but I originally asked in an unrelated
thread
>> and thought it would be better to break this out into a separate thread
and
>> I added some other thoughts.
>>
>> I am seeing the following error on a program with long running
transactions:
>>
>> Fatal Error: in fn MemoryTransactionResult
>> SimicsProcessor::makeRequest(memory_transaction_t*) in
>> simics/SimicsProcessor.C:365: Error: Simics get unstalled without ruby
>> asking?
>>
>> Has anyone seen this before / have any advice to avoid it?  This error
>> message is thrown inside of SimicsProcessor::makeRequest, would it be
safe
>> to just throw a warning instead of an error?  Or is there some timeout
value
>> that I need to increase to prevent Simics from getting unstalled since I
am
>> dealing with long running transactions?
>>
>> Here are all of the messages I see:
>>
>> Warning: in fn void RegisterState::enableInterrupts(int) in
>> log_tm/RegisterStateWindowed.C:336: "WARNING: in enable interrupts" is
>> WARNING: in enable interrupts
>> Warning: in fn void RegisterState::enableInterrupts(int) in
>> log_tm/RegisterStateWindowed.C:336: "WARNING: in enable interrupts" is
>> WARNING: in enable interrupts
>> Warning: in fn void RegisterState::enableInterrupts(int) in
>> log_tm/RegisterStateWindowed.C:337: pil is 0
>> Warning: in fn void RegisterState::enableInterrupts(int) in
>> log_tm/RegisterStateWindowed.C:337: pil is 0
>> Fatal Error: in fn MemoryTransactionResult
>> SimicsProcessor::makeRequest(memory_transaction_t*) in
>> simics/SimicsProcessor.C:365: Error: Simics get unstalled without ruby
>> asking?
>> Fatal Error: in fn MemoryTransactionResult
>> SimicsProcessor::makeRequest(memory_transaction_t*) in
>> simics/SimicsProcessor.C:365: Error: Simics get unstalled without ruby
>> asking?
>>
>>
>> Thanks for any help anyone can provide,
>>
>> Mark
>>
>>
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>>  
>>
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