Messages in this thread | | | Subject | Re: SMP cpu deep sleep | From | Benjamin Herrenschmidt <> | Date | Sat, 21 Aug 2004 10:53:45 +1000 |
| |
On Sat, 2004-08-21 at 02:44, Wes Felter wrote:
> The CPU hotplug patch is the way to go, but the hardware is the problem. I > talked to an Intel CPU architect at MICRO last year and he confirmed that > SMP Intel systems don't support any low-power modes besides HLT. AMD's > documentation says that Opterons support voltage/frequency scaling (aka > Cool 'n' Quiet), but AFAICT the documentation is wrong. In summary, you > are doomed.
Well, with intel CPUs maybe ;) On PPC we can put some CPUs (at least the desktop ones and the 970, I don't know about POWER3/4/5) into SLEEP mode after flushing all caches & masking all IRQs to them, and get them out via an IPI, or we can mask EE as well and get them out via a soft reset if we have access to it.
Ben.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |