Alan Jenkins wrote: > > AFAIK: The headline figure would be %age time in C4.
yup > I'm thinking > the avg residency figure doesn't actually add anything to that. that's not quite the case unfortunately. > Transitioning to/from C4 takes some time, during which power is being > drawn but no productive work done. However if you spend more time in > transitions but the same time in C4, all that means is you got less > time doing productive work; there might be no difference at all in > terms of power usage. transitions are actually quite expensive (well everything is relative of course); it means analog parts of your chip need to go on or off. Think of it as with traditional light bulbs; when they turn on they briefly take a lot more current than when they're fully enabled. (this is also why they break at this point more often) Depending on the cpu type, the time you want to be in C4 ranges from 20msec to 50msec. (this assumes current cpus; future cpus might and will vary). Above 50msec you'll not see much power difference today. So the answer to the original question is something like: * try to get C4 %age above 99% * try go get average time there above 50msec _______________________________________________ Power mailing list [email protected] http://www.bughost.org/mailman/listinfo/power
