On Dec 8, 2008, at 3:49 PM, Ryan Markley wrote:

> Hello,
>
> I have a system with 4 cpu and one L2 cache shared with all of the
> cores, I am doing the simulations with the detail cpu. I am interested
> in study how the cores access to the shared cache. I have been looking
> in the code of mem/bus.cc and mem/bus.hh. In the file bus.cc there is
> a function called  recvTiming, this is the function that is used to
> access to the bus and when the bus is busy the accesses are stored in
> a retryList, but my question is: is this the function used to access
> to the shared cache?
Ultimately, yes. When it is able to it will call sendTiming() on the  
port that connects to the L2 cache. However, if you want to look at  
the L2 cache specifically, it would probably be better to look at the  
actual cache and put any instrumentation you like inside there.

> or it is used only to access to the main memory.
> I have been printing the accesses in the retryList , but I do not see
> enough access from the different cores, that's why I am thinking that
> maybe that retryList is not the retryList for the shared cache.
The retryList only is populated when the bus cannot send the request  
immediately. If you're in the cache the request object has various  
fields that identify the CPU it's coming from (contextId() and  
threadId()),

> And another question is there a way to assign a core per program in
> full system mode, I know that is a linux question and not a M5
> simulator problem, but I would like to know if anybody knows a way to
> assign a program to each core.
You can do it with the sched_setaffinity() system call. Nate just  
pushed a change to the m5 binary (which stays on the disk image) that   
allows a syntax like m5 pin <cpu id> <program to run>, however you can  
just call sched_setaffinity from your workload if you like. However, I  
believe that the disk image we supply doesn't support that system  
call, so you would need to get the gentoo alpha disk image or create  
you own with a newer  glibc on it.

Ali

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