Sorry, I should have been more clear. It fundamentally comes down to how does the Ruby interface help support memory consistency, especially considering more realistic buffering between the CPU and memory system (both speculative and non-speculative). I'm pretty certain that Ruby and the RubyPort interface will need be changed. I just want us to fully understand the issues before making any changes or removing certain options. So are you advocating that the RubyPort interface be the line between speculative memory state and non-speculative memory state?
As far as the current Ruby store buffer goes, how does it work with the L1 cache controller? For instance, if the L1 cache receives a probe/forwarded request to a block that exists in the non-speculative store buffer, what is the mechanism to retrieve the up-to-date data from the buffer entry? Is the mechanism protocol agnostic? Brad > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Arkaprava Basu > Sent: Wednesday, February 23, 2011 6:10 PM > To: M5 Developer List > Subject: Re: [m5-dev] Store Buffer > > Hi Brad, > > I have very little knowledge about the store buffer > implementation in libruby and o3 CPU model. But I have following high > level question: > > Is this Store buffer in libruby only for keeping retired > (non-speculative) stores ? If yes, then why a particular CPU models > matters here? In-order cores (CPU models) can also use (retired) store > buffer. I believe its is an issue of memory consistency model being > simulated rather than tied to a particular CPU model > (in-oder/out-of-order). Please correct me if I am totally missing > something here. > > Thanks > Arka > > On 02/23/2011 07:07 PM, Beckmann, Brad wrote: > > That's a good question. Before we get rid of it, we should decide > what is the interface between Ruby and the o3 LSQ. I don't know how > the current o3 LSQ works, but I image that we need to pass probe > requests through the RubyPort to make it work correctly. > > > > Does anyone with knowledge of the o3 LSQ have a suggestion? > > > > Brad > > > > > >> -----Original Message----- > >> From: [email protected] [mailto:[email protected]] > >> On Behalf Of Nilay Vaish > >> Sent: Wednesday, February 23, 2011 4:51 PM > >> To: [email protected] > >> Subject: [m5-dev] Store Buffer > >> > >> Brad, > >> > >> In case we remove libruby, what becomes of the store buffer? In > fact, is > >> store buffer in use? > >> > >> Thanks > >> Nilay > >> _______________________________________________ > >> m5-dev mailing list > >> [email protected] > >> http://m5sim.org/mailman/listinfo/m5-dev > > > > _______________________________________________ > > m5-dev mailing list > > [email protected] > > http://m5sim.org/mailman/listinfo/m5-dev > _______________________________________________ > m5-dev mailing list > [email protected] > http://m5sim.org/mailman/listinfo/m5-dev _______________________________________________ m5-dev mailing list [email protected] http://m5sim.org/mailman/listinfo/m5-dev
