Thanks for the contribution... this is helpful perspective, not butting in at all.
I agree that it would be best not to give the impression that McPAT is the "official" power model for gem5. There's no intention to make it so, and I believe that some of us have other internal power models that we use with gem5, but which can't be shared publicly. This sounds like a reasonable argument for creating a separate repo rather than putting McPAT in ext. What do others think? It still seems clear that we should move ahead with hosting our own McPAT branch though (whether separate or in ext). I haven't heard anyone suggest otherwise. Let's not lose the momentum on this... Steve On Wed, Sep 25, 2013 at 8:41 AM, Erik Tomusk <[email protected]> wrote: > Having spent far too much time with McPAT's source code, I thought I'd > butt in here. The lack of a repo is a problem for myself and others using > McPAT, but for every reason to include the McPAT source with gem5, I can > think of a good reason not to. > > The biggest problem with including McPAT, IMO, is that it implies that > McPAT is fit for the purpose of modeling power for gem5. I'm not sure this > is the case, at least for the official McPAT release. Beyond quality of > code issues with McPAT (and there are many), McPAT's microarchitectural > model is only somewhat similar to gem5's. More often than not, there is no > simple one-to-one correspondence between McPAT's and gem5's parameters. > > I'd argue that it's worth hosting a McPAT repo separately from gem5 to see > if a community of users and developers emerges. If McPAT's quality reaches > gem5's, then distributing McPAT as standard is a good option. At the > moment, though, the amount of magic required to get McPAT to work with gem5 > is such that I don't think bundling McPAT is a good idea. > > It's maybe also worth considering if it's good for the broader community > that a simulator and power model are developed so closely in tandem. > Ideally we'd like our simulators and power models at least somewhat > modular, so we don't end up with a repeat of Wattch only being usable with > SimpleScalar. > > -Erik > > > > On 21/09/13 22:46, Steve Reinhardt wrote: > >> On Fri, Sep 20, 2013 at 8:46 AM, Nathan Binkert <[email protected]> wrote: >> >> On Sept. 20, 2013, 7:46 a.m., Andreas Hansson wrote: >>>> >>>>> I do not really see the point here. Could you be more clear around >>>>> >>>> what this "integration" would involve? In any case, I would vote not to >>> include the McPat source in gem5, and if it really needs to live in the >>> source tree, get the users that want to have it to clone/checkout in >>> ext/mcpat. >>> >>> I agree. Shouldn't McPAT be maintained in its own repository? Shouldn't >>> it just use EXTRAS? >>> >>> The point is that everyone has patches/fixes etc. for McPAT, and since >> HP >> doesn't seem to be actively accepting patches and updating their version, >> if we host our own version then at least we can share patches amongst >> ourselves and not duplicate effort. I'm not sure how much of this >> involves >> gem5-specific changes vs. just general power model fixes, but there are at >> least plenty of the latter. >> >> Ron, Brad, Ali, and I were at the DOE ModSim workshop last week discussing >> this problem, and hosting our own version of McPAT seemed to be the best >> solution (in the near term, anyway). >> >> Another option is just to host a separate McPAT repo on repo.gem5.org. >> That's OK with me too. When I suggested doing this instead of putting >> it >> in ext, Ali said "why not put it in ext?", and I don't have any great >> answer for that. In general, we've maintained separate repos on >> gem5.orgprimarily because of license issues (e.g., EIO and the >> >> softfloat >> discussion), and that doesn't apply here. So I see the argument for >> putting it in ext, but I don't feel strongly about it either way. >> >> Steve >> ______________________________**_________________ >> gem5-dev mailing list >> [email protected] >> http://m5sim.org/mailman/**listinfo/gem5-dev<http://m5sim.org/mailman/listinfo/gem5-dev> >> >> > > -- > The University of Edinburgh is a charitable body, registered in > Scotland, with registration number SC005336. > > > ______________________________**_________________ > gem5-dev mailing list > [email protected] > http://m5sim.org/mailman/**listinfo/gem5-dev<http://m5sim.org/mailman/listinfo/gem5-dev> > _______________________________________________ gem5-dev mailing list [email protected] http://m5sim.org/mailman/listinfo/gem5-dev
