Re: [Gems-users] cache flushing

[Mladen Nikitovic <mladen@xxxxxx>]

Mike Marty wrote:
> You need to flush the private caches of that processor.  In an actual 
> system, you would have to write back all dirty data to memory.  In 
> Simics+Ruby, you could possibly cheat because Ruby doesn't keep track of 
> data.  However even that isn't so simple because if you do have shared 
> data that is owned by the processor being shutdown, then you really do 
> need to initiate replacement operations so that the directory would not 
> generate forward messages to your shutdown processor.  
>
> So I think first you need to make sure all outstanding requests finish 
> at that processor, then you need to walk the cache and initiate 
> replacement operations for every cached line. 
>
>   
  I was afraid of that :) Is this needed replacement operation already 
implemented in GEMS? This also relates to my earlier question (in 
another thread) regarding how to detect the number of replacements 
performed on a cache on a per-processor basis...
> In other words, I don't think shutting down a processor is as easy as 
> just wiping the CacheMemory objects, TBEs (transaction buffer 
> entry...otherwise known as MSHRs), etc.
>   
> --Mike
>
> Mladen Nikitovic wrote:
>   
> > Hi,
> >
> > right, that makes sense. I didn't shutdown the processor at that time, 
> > so I can imagine the scenario that you described.
> > I have a follow up-question: If I want to simulate the side-effects of a 
> > processor shutdown by flushing the context of all buffers and memories 
> > on that particular processor, which structures do I need to consider?
> > So far, I am only flushing the i- and d-cache. I know there is a 
> > store-buffer somewhere, a directory for the cache, and I guess there is 
> > a TLB also, but I cannot find the structure name for it. By the way, 
> > what does TBE stand for?
> > Are there any other structures I have forgotten?
> >
> > Thanks for your help.
> >
> > /Mladen
> >
> >   
> >     
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