I would like to experiment with these two different scenarios:

1) 4 CPUs at 2GHz sharing 1 L1 cache at 2GHz

vs 

2) 4 CPUs at 2GHz sharing 1 L1 cache at 8GHz

I am not sure if this would work with ruby but if not I could
try with Simple Memory Module.

Do you have any suggestions on which code to modify?
I am new to gem5 and I am trying to get familiar with it.

Pavlos

On Fri, 2012-11-23 at 17:06 +0000, Jack Harvard wrote:
> Why not, just put a bus in between CPUs and L1? But why would you do
> so?
> 
> Jack Harvard
> 
> 
> On Fri, Nov 23, 2012 at 4:06 PM, Pavlos Maniotis
> <[email protected]> wrote:
>         Thanks Andreas,
>         
>         I would like to ask you one more thing:
>         Do you believe it is feasible to simulate
>         a system with L1 shared cache among cpus (either with ruby or
>         with
>         Classic Memory System)? I have searched the mailing list but
>         I couldn't find some helpful info.
>         
>         On Fri, 2012-11-23 at 14:38 +0000, Andreas Hansson wrote:
>         > Hi Pavlos,
>         >
>         > There have been numerous discussions around the CPU to L1
>         > bandwidth/latency, and by default it is not limited (i.e. it
>         is just two
>         > ports connected together). IF you want (and as Steve has
>         previously
>         > pointed out) you can insert a CoherentBus between the CPU
>         and L1 if you
>         > want, but you will have to change the config scripts.
>         >
>         > Good luck.
>         >
>         > Andreas
>         >
>         > On 23/11/2012 14:34, "Pavlos Maniotis"
>         <[email protected]> wrote:
>         >
>         > >Hi Andreas,
>         > >
>         > >Thanks for the info, does it also apply for the Classic
>         Memory System?
>         > >I was thinking that there was a bus between CPU and L1 with
>         some width
>         > >and some frequency, for example 64bit and 2GHz. I wanted to
>         test two
>         > >different systems and compare the performance between them:
>         > >
>         > >1)  CPU (2GHz) <--------[bus 64 width, 2GHz]---------> L1
>         (2GHz) ->to L2
>         > >2)  CPU (2GHz) <--------[bus 32 width, 4GHz]---------> L1
>         (4GHz) ->to L2
>         > >
>         > >Do you think that I cannot use gem5 to do this experiment?
>         > >
>         > >Thanks again,
>         > >Pavlos
>         > >On Fri, 2012-11-23 at 14:14 +0000, Andreas Hansson wrote:
>         > >> Hi Pavlos,
>         > >>
>         > >> There is no bus between the CPU core and the L1, just a
>         "port"
>         > >>connection.
>         > >> The PIO bus is only used for PIO, and should not have a
>         great impact on
>         > >> your benchmark unless it is very I/O intensive.
>         > >>
>         > >> Andreas
>         > >>
>         > >> On 23/11/2012 12:29, "Pavlos Maniotis"
>         <[email protected]> wrote:
>         > >>
>         > >> >Hello everyone,
>         > >> >
>         > >> >I use ruby (MOESI_CMP_directory) and I want to simulate
>         a system
>         > >> >with one CPU (frequency=2GHz) and L1 and L2 caches
>         (frequency=4GHz).
>         > >> >I also want the bus between cpu and cache
>         > >> >to run at 4GHz with width 32 bits. So I have to set the
>         cpu
>         > >> >frequency equal to 4GHz (ruby_fs.py -> CPUClass.clock =
>         '2GHz')
>         > >> >and ruby frequency equal to 2GHz
>         > >> >(Ruby.py ->     system.ruby = RubySystem(clock = 4,
>         > >> >                             stats_filename =
>         options.ruby_stats,
>         > >> >                             no_mem_vec =
>         options.use_map)).
>         > >> >
>         > >> >I suppose these changes are right, my main concern is:
>         > >> >
>         > >> >Do I have to change system.piobus frequency
>         > >> >to 4GHz and width to 4 bytes (file FSConfig.py, function
>         > >> >makeLinuxAlphaRubySystem)?
>         > >> >Is this the bus between cpu and L1 cache? If it is not
>         > >> >how can I configure the bus between L1 and CPU?
>         > >> >
>         > >> >I am little bit confused about the interconnection
>         system.
>         > >> >
>         > >> >Thanks in advance for any help,
>         > >> >Pavlos
>         > >> >
>         > >> >
>         > >> >_______________________________________________
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