> Ah. :) So DR on x86 doesn't exist yet. DR allows deletion of the CPU > from the system, to the extent where the CPU can be > powered off. This obviously requires support from the hardware. On x86, > taking the CPU offline (where it is essentially parked in the C1 > state down in the idle() loop) is as low as we can go right now.
I don't think I mentioned this before, but the architecture we are currently targeting is SPARC. DR does exist on that, right? > What a coincidence. We've been thinking about this as > well. :) We think that having a power management aware > dispatcher is important for a few reasons: > - Existing performance optimizing dispatcher > policy that emphasizes preading out load across the system > (optimizing for CMT, for example) tends to > minimize availability of power manageable CPU resources. Having > a "default" policy where the dispatcher considers both throughput > nd power efficiency would be better. > - CPU PM policy will be more effective if the dispatcher cooperates. > - The system will perform better (overall) given > a PM aware dispatcher since it won't by trying to schedule things > to run on CPUs that have been clocked down. > the next week or so, i'd like to kick off a project > to go down the road of making the dispatcher power aware. Perhaps > that would be a good way for us (and interested others) to > collaborate? A collaboration would certainly be interesting and useful. However there are a few things that come to mind: - I am not sure whether this would be architecture-specific. The dispatcher code is common, but power management would probably not... If you are looking into x86 and I'm into SPARC, then this could either be a problem, or complementary. - Timeline: my work is in the context of a master thesis, which should be finished before July 2007. By then, the actual implementation should hopefully be already finished for some time so I have the time to concentrate on writing the report. I am not sure how long a complete implementation would take, or which timeline you had in mind. In case yours is much longer than, say, May, then we might need to keep separate projects (with of course the possibility to communicate). - The purpose of my thesis project is to implement a periodic shutdown of processors in OpenSolaris: each period (period length is a parameter) the idleness of all processors will be evaluated and idle processors will be taken offline). The whole idea is to save energy for battery-powered devices. Obviously, implementing this is much more specific than creating a complete well-written power-aware scheduler. Due to my time constraints, the latter could be unfeasible for me to cooperate on. I think it all depends on your plans and timeline. Please let me know your thoughts about this, Thomas > _______________________________________________ > opensolaris-code mailing list > [email protected] > http://mail.opensolaris.org/mailman/listinfo/opensolar > is-code > This message posted from opensolaris.org _______________________________________________ opensolaris-code mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/opensolaris-code
