Re: [Gems-users] Gems-users Digest, Vol 136, Issue 5

[Guoqiang Yang <nkyangguoqiang@xxxxxxxxx>]

Hi Niket,

Thanks for your reply.
> ------------------------------
>
> Message: 3
> Date: Thu, 01 May 2008 22:39:13 -0400
> From: Niket <niketa@xxxxxxxxxxxxx>
> Subject: Re: [Gems-users] About the bandwidth model inside GEMS and
> 	length unit	of links
> To: Gems Users <gems-users@xxxxxxxxxxx>
> Message-ID: <481A7ED1.8070907@xxxxxxxxxxxxx>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
>   
> > I'm quite sure that GEMS 2.0 with a bandwidth model for the links which 
> > I can find in Throttle.h[.C]. But for GEMS 2.1 with Garnet integrated, 
> > do you guys also model the bandwidth? Could anyone know about this model 
> > give me a pointer to that?
> >   
> >     
> Limited bandwidth is modeled in Garnet. The FLIT_SIZE parameter defines 
> the number of bytes/cycle that can cross a link.
>   
g_FLIT_SIZE is defined in rubyconfig.default, but I guess that paramter 
is used to determine the size of each flit, it means that 1 flit = 16B. 
Is that right? If it can also be interpreted as bandwidth parameter, 
does that mean that the bandwidth is really 16B/cycle, or 1 flit/cycle 
for the links? That turns into 32GB/s for 2Ghz frequency system?
> > I also have question about how you calculate the per-access power 
> > consumption for the links in the Interconnection Network. Currently you 
> > use fixed length for the wires, my question is really what is the unit 
> > of the length then?
> >     
> You can find this information in Orion files. I just use the default 
> length.
I found that information in the parm_technology.h, and the link length 
is really defined as 1000 um long.
 

> Niket
> -----------------------------
Many thanks,

Guoqiang Yang