Jose Rodriguez wrote: >>> >>> I installed 2.6.24 and everything seems OK except that my CPU >>> spends about 75% of its time in C2: >>> <...> > > Hi and thanks for the reply. > > I had reduced the beacon frequency before and after upgrading to > 2.6.24 and although it makes a bit of a difference it doesn't > account for the time my processor is in C2-now I'm back to the > default 100 ms for it seems that a Vista laptop has problems > connecting to the router in these conditions. So to recap, 2.6.24 > compiled from source as well as from Debian repos (hpet=force) do > show a behavior not seen before with 2.6.22 with the mentioned patches. > > I'll try to chase down this a bit further if I can. >
>From http://www.lesswatts.org/projects/powertop/faq.php ------------------------------------------------ Why did my power usage increase with dynticks? Why do I never reach sleep states deeper than C2? The current ACPI sleep function requires wakeups to reach deeper sleep states. Certain drivers, such as ipw2200, limit the initial sleep state to C2 due to DMA activity. With dynticks, which tries to sleep as long as possible, this means that your processor will, most of the time, only reach C2 and thus waste power compared to a non-dynticks kernel if it is mostly idle. This will be solved by an upcoming cpuidle patch. Until this hits mainline, you should compare your power usage with and without dynticks (and maybe with different HZ values) to figure out which is currently the best for your workload. ------------------------------------------------ Though it looks like exactly the opposite has happened - 2.6.22 (without cpuidle) had no problems and 2.6.24 (with cpuidle) has trouble going to the sleep states deeper than C2. _______________________________________________ Power mailing list [email protected] http://www.bughost.org/mailman/listinfo/power
