Re: [Gems-users] gems-users@xxxxxxxxxxx;gems-announce@xxxxxxxxxxx

["Liangliang Tong" <nutspea@xxxxxxxxxx>]

Thanks Greg.
Another questions, which are marked by //??, thanks in advance.

// Check to see if it is in the OTHER L1
          if (L1IcacheMemory.isTagPresent(in_msg.Address)) {
// The block is in the wrong L1, put the request on the queue to the shared L2
            trigger(Event:L1_Replacement, in_msg.Address);
          }
          if (L1DcacheMemory.isTagPresent(in_msg.Address)) { 
            // The tag matches for the L1, so the L1 ask the L2 for it
           //?? when the tag matches, why L1 need request the L2? Another typo?
what does event "mandatory_request_type_to_event(in.msg.Type)" fetch? Sorry to ask
such a simple question, 'cause I can not locate where the
"mandatory_request_type_to_event" function is.

            trigger(mandatory_request_type_to_event(in_msg.Type),
in_msg.Address);
          } else {
            if (L1DcacheMemory.cacheAvail(in_msg.Address)) {
   // L1 does't have the line, but we have space for it in the L1 let's see if the
L2 has it
//?? Another same event for different cases. When cacheAvail, the L1 need to
requese data from L2, doesn't it?
              trigger(mandatory_request_type_to_event(in_msg.Type),
in_msg.Address);

            } else { 
              // No room in the L1, so we need to make room in the L1
              trigger(Event:L1_Replacement,
L1DcacheMemory.cacheProbe(in_msg.Address));
 




In your mail:
>From: Greg Byrd <gbyrd@xxxxxxxx>
>Reply-To: Gems Users <gems-users@xxxxxxxxxxx>
>To: Gems Users <gems-users@xxxxxxxxxxx>
>Subject: Re: [Gems-users] gems-users@xxxxxxxxxxx;gems-announce@xxxxxxxxxxx
>Date:Thu, 08 May 2008 21:43:33 -0400
>
>Liangliang Tong wrote:
> > Hello everyone, when I am verifying one of my idea using gems, there are
several
> > questions I fail to figure out:
> > 
> > 1) In the MESI_CMP_directory protocol, there is a status called "idle",
whereas
> > the traditional status is "invalidate", so I wonder is there any differences
> > between these two statuses? if different, how?
> 
> No difference.  It means what you think it means.
> 
> > 
> > 2)  IS, desc="L1 idle, issued GETS, have not seen response yet";
> >     IM, desc="L1 idle, issued GETX, have not seen response yet";
> >     SM, desc="L1 idle, issued GETX, have not seen response yet";
> >     IS_I, desc="L1 idle, issued GETS, saw Inv before data because directory
> > doesn't block on GETS hit";
> > 
> >     M_I, desc="L1 replacing, waiting for ACK";
> >     E_I, desc="L1 replacing, waiting for ACK";
> > 
> > I just can not understand the explainations in the " ", they are the same for
IM
> > and SM, or M_I and E_I? could anyone explain these four transient statuses 
to
> > me?
> 
> For SM, this is a typo.  Should be "L1 shared, issued GETX, ..."
> 
> For M_I and E_I, the explanations are accurate.  In both cases, the line is 
> replaced and the ACK has not been seen.  The only difference is the starting
state.
> 
> ...Greg
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