Hi Christian, V po, 30. 06. 2008 v 18:31, Christian Walther p??e: > Hello List, > Hello Milan, >
I missed this e-mail yesterday because of wrong e-mail address ;-) > I just subscribed to this list after I installed OpenSolaris on my > Athlon X2 powered server at home. The issue here is powernowd. > > In a message I found in the "PowerNow AMD Athlon64 X2 (dual core)" > Milan Jurick stated: > > "If you motherboard supports Barcelona based AMD, then > change to that CPU." > URL: > http://mail.opensolaris.org/pipermail/laptop-discuss/2008-June/010647.html > > I just migrated from FreeBSD to OpenSolaris because of the features > Solaris offers. But since the server is located at home, saving power > is an issue. > What I don't understand is what one would gain by replacing the CPU > with a Barcelona based one? > > I'm just asking because changing the CPU might really be an option > here, as long as there really is some power saving so that the > additional costs are covered eventually. > The problem with pre-Barcelona and very old Intel P4 CPUs is in TSC register, counting CPU cycles. It's the quickest source of time in x86. But TSC isn't frequency invariant in these CPUs, so Opensolaris, depending on accurate time source heavily, can't change frequency of these CPUs. In Barcelona (K10) and the current Intel CPUs the register is updated "independently" on CPU frequency. Casper Dick created special powernow driver, which is able to change frequency on single core Athlons, be resyncing time counters, but to do it on dual core it would be very invasive and would require significant redesinging of system core. If you will not miss the second core and your BIOS allows to switch to single core mode, you can try to use Dick's frkit. Best regards, Milan
