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

[Greg Byrd <gbyrd@xxxxxxxx>]

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