Re: [Gems-users] The size of L2 Cache

["Mike Marty" <mikem@xxxxxxxxxxx>]

Hi May,

In the $GEMS/ruby/config/RubyConfig.C, there is this line that manipulates
the L2_CACHE_NUM_SETS_BITS:

  L2_CACHE_NUM_SETS_BITS = L2_CACHE_NUM_SETS_BITS -
log_int(g_NUM_L2_BANKS_PER_CHIP);

So if you bank the L2, it changes the variable so you specify the total L2
size and each individual cache bank uses the new parameter.  

Can you check this?

--Mike


> 
> 
> Hi,
> 
>         I have tried ruby0.set_param L2_CACHE_NUM_SETS_BITS 13 before 
> ruby0.init , but in "ruby.stats" L2_CACHE_NUM_SETS_BITS is 
> still 10. At 
> this time, g_NUM_PROCESSORS=4. However if I use ruby0.setparam 
> g_NUM_PROCESSORS 8, and then ruby0.set_param 
> L2_CACHE_NUM_SETS_BITS 13. 
> Surprisingly in "ruby.stats",
> L2_CACHE_NUM_SETS_BITS is 11, not 10, not 13.
>         Could you help me to check it in your system? I am 
> using GEMS 1.1.
>         Thanks again.
> 
> May
> 
> 
> At 09:37 AM 4/03/2006 -0600, you wrote:
> > > Hi Min and Michelle,
> > >
> > >       Thanks for your help.
> > >       I want to get 2M bytes L2 cache. Becaue 
> DATA_BLOCK_BITS=6 and 
> > > L2_CACHE_ASSOC=4, L2_CACHE_NUM_SETS_BITS should be set to 13. Is 
> > > that
> > right?
> > >
> >
> >2^13 sets * (4 blocks/set) * (64 bytes/block) = 2 MB
> >
> >Yes, it is correct.
> >
> >Note for CMP protocols, the L2 cache size is specified for 
> the entire 
> >chip (not per-bank which is what the stats will show) 
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> 
> 
> 
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