Gabe, Can you step-by-step explain what's inaccurate about the current TLB process?
On Wed, Jan 14, 2009 at 6:31 PM, <[email protected]> wrote: > Has anyone had a chance to give this some thought? Could Kevin/Korey > comment on > how hard they think it would be and/or how much overhead there would be to > make > translation be deferrable in O3? > > Gabe > > Quoting [email protected]: > > > I've been putting off starting a discussion about this since I know some > > people > > are otherwise occupied, but it would be useful for it to at least be in > the > > back of someones mind. I haven't spent a huge amount of time thinking > about > > this recently, but I see two possible ways to handle it. > > > > 1. Translation is reworked so that it can be delayed like memory > transations. > > In > > atomic mode it could be blocking and immediate, and in timing mode the > CPU > > would > > get a call back. This isn't ideal because it would require changes to the > CPU > > models which would potentially cause performance overhead for the other > ISAs, > > potentially break ARM (more?), and would be painful to add to O3 in the > long > > term. It's the most realistic, though, in terms of mimicking actual CPUs. > > > > 2. Make the TLB miss fault invoke whichever other faults may come up > inside > > it's > > own invoke method. This would be comparatively easy, but would be > inaccurate > > as > > far as performance. It also goes behind the CPU's back as far as who is > in > > control of faults/exceptions, etc., and could cause problems with generic > > statistics for instance. I don't know if such statistics exist. > > > > Gabe > > > > _______________________________________________ > > 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 > -- ---------- Korey L Sewell Graduate Student - PhD Candidate Computer Science & Engineering University of Michigan
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