Re: [Gems-users] SIMICS SEG FAULT on transaction retry [ruby]

[Jayaram Bobba <bobba@xxxxxxxxxxx>]

mgill404@xxxxxxxx wrote:
> I am currently running the STAMP 0.9.9 benchmarks on the newest  
> version of gems [2.1] and the newest version of simics [3.x].  The  
> benchmarks run fine unless there is a need for a transaction to retry,  
> in which event it halts with a "SIMICS SEG FAULT" message.  My  
> benchmarks run to completion in the event that there just happens to  
> be no collision.  I suspect it is a coincidence, but this problem has  
> so far always occurred on processor 0 [pset 1].
> The setup I am using consists of running a benchmark up to immediately  
> before it would begin transactions, and saving the configuration  
> there.  I then restart simics and load the configuration, and load  
> ruby at that point.  Because STAMP requires a x^2 number of running  
> threads, and ruby requires x^2 processors, I have attempted to run the  
> majority of these tests with 1 thread per processor, thus resulting in  
> the last thread being unbound [due to inability to assign a processor  
> set to all processors].  I have also attempted to run such benchmarks  
> on a simulated machine using only half the processors available,  
> binding every running thread, and experienced the same problems.
> Any advice to help me resolve this situation would be greatly  
> appreciated.  This is becoming quite frustrating.  Any ideas would be  
> welcome.
>   
Can you generate more debugging output by setting XACT_DEBUG to true
and XACT_DEBUG_LEVEL to 2 or higher. I would be interested in looking at
the output just before the retry.
> Also, I have already adjusted the offset in 'set transaction  
> registers' to point to [what I believe to be] the correct position to  
> handle a retry [+36].  As a side question, would having this offset  
> set incorrectly result in the error that I am seeing?
>   
Possible, but incorrect offset mostly shows up as a segmentation fault
in the program being run on the simulated machine and not as a SIMICS
SEG FAULT.

Jayaram