Re: [Gems-users] Process ID

[Philip Garcia <pcgarcia@xxxxxxxx>]

I don't know how to get the PID, but you can get a context identifier  
for the process that is running on a given CPU.  This is a bit tricky  
though.   The actual PID is an OS construct that I don't think is  
available from simics.   The context identifier is another OS specific  
variable, but they seem to be unique per thread.   I think this is  
stored because the PID would be the same on all threads of a  
multithreaded application, and the OS scheduler needs to be concerned  
with thread scheduling more so than process scheduling.
That said, if you can get the processor number of the cache miss, it  
is possible to get the context with the following code:
conf_object_t *cpu, mmu_obj;
cpu=SIM_get_processor (ProcessorNumber);
mmu_obj=SIM_get_attribute(cpu, "mmu").u.object;
CPU_CTX=SIM_get_attribute(mmu_obj,"ctxt-primary").u.integer & 0x1fff;

One thing to be careful with though is that the processor number is  
likely not just the node id within ruby.   I am only familiar with the  
sunfire (bagle) machine, but the processors are numbered oddly there,  
and have the following numbers in simics:  cpu0,cpu1,cpu4,cpu5 .. .   
and I don't know after that offhand.   The serengeti machines likely  
do something different, so you'd have to check in simics what the  
processor ordering is.   Also, if you enable SMT inside opal, things  
might get more difficult, as the ruby node id doesn't directly  
translate to a CPU number.  I am not positive if the requests sent  
into ruby have actual cpu ids embedded in them, if not, you might have  
to add that.
Phil
On Dec 16, 2009, at 1:17 PM, blacuesa wrote:

> Hello,
>
> Does anyone know if it is possible to get the PID of the process  
> that has
> caused a specific cache miss? I've tried to it by using the  
> parameters of the
> "ruby_operate" function, but I didn't achieved it.
>
> Thanks in advance!
>
> Regards.
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