Re: [Gems-users] Private L2 in a CMP...

[Greg Byrd <gbyrd@xxxxxxxx>]

What's the problem with using a unified L2 cache?  Unified does not mean 
"shared".  For a two-processor system, a broadcast protocol makes the 
most sense.

David Bonavila wrote:
> Ruby says "/Non-CMP protocol should set g_PROCS_PER_CHIP to 1/" when 
> using a SMP protocol and g_PROCS_PER_CHIP greater than 1, so I guess I 
> will have to set g_PROCS_PER_CHIP to 1 and g_NUM_PROCESSORS to 2 to 
> model a 2-core CMP.
> There are 3 SMP protocols, and the first two of them use a unified L2 
> cache, so can I only use MOESI_SMP_hammer??
> Which network latency parameters should I set to have a good approach 
> of a CMP using 2 chips??
> Thank you!!
>
>
> 2009/6/15 David Bonavila <david.bonavila@xxxxxxxxxxxxxxxxxx>
>
>
>     OK, thanks.
>     I need to model a 2-core CMP with private L2 for each of the cores.
>     Then, how should I configure these parameters?? I guess it should
>     be something like this:
>
>
>     ruby0.setparam g_PROCS_PER_CHIP 1
>     ruby0.setparam g_NUM_PROCESSORS 2
>
>     Is that right?? Should I set any other parameters or configuration??
>     I have read something about making a fast interconnect between
>     chips. Do I need any of that??
>
>     Thank you again!!
>
>
>     2009/6/15 David Bonavila <david.bonavila@xxxxxxxxxxxxxxxxxx>
>
>
>         Hi.
>
>         I need to configure a CMP with a private L2 cache, and I would
>         like to know which of these configs I should use:
>
>         1)
>         ruby0.setparam g_PROCS_PER_CHIP 1
>         ruby0.setparam g_NUM_PROCESSORS 2
>
>         2)
>         ruby0.setparam g_PROCS_PER_CHIP 2
>         ruby0.setparam g_NUM_PROCESSORS 2
>         ruby0.setparam_str g_CACHE_DESIGN PRIVATE_L2
>
>         3)
>         ruby0.setparam g_PROCS_PER_CHIP 1
>         ruby0.setparam g_NUM_PROCESSORS 2
>         ruby0.setparam_str g_CACHE_DESIGN PRIVATE_L2
>
>         As I want to simulate a CMP, I guess I should use config
>         number 2, but I don't know if that is the right way to do what
>         I want.
>         Does config number 1 (without the g_CACHE_DESIGN parameter)
>         provide a private L2 cache??
>         Or is any of them acceptable and the result will be the same??
>
>         Thanks!!
>
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> Gems-users mailing list
> Gems-users@xxxxxxxxxxx
> https://lists.cs.wisc.edu/mailman/listinfo/gems-users
> Use Google to search the GEMS Users mailing list by adding "site:https://lists.cs.wisc.edu/archive/gems-users/"; to your search.
>
>