e600 core power management

e600 core power management

[Matt Sealey]

Hi guys,

Quick question, am I right (and looking at idle_6xx.S, I think I am) in thinking that
during the idle process, by default, an e600 core such as the 7448 or MPC8610 will
automatically transition to a NAP state, thus being as low power as possible?

Has anyone done any benchmarking of the power consumption of the processor when
this transition is disabled (remove CPU_FTR_MAYBE_CAN_NAP) or have a rough idea
what the benefits might be?

Is there a performance reason for removing the feature or disabling naps altogether?
The powersave-nap sysctl controls whether DOZE or NAP is entered on processors that
support a seperate HID0[DOZE], however is it possible to extend it such that nap
is never entered?

-- 
Matt Sealey <matt@genesi-usa.com>
Genesi, Manager, Developer Relations

Re: e600 core power management

[Matt Sealey]

I think I'll reiterate here as it got lost in my rambling, that I am wondering
if NAP is enabled *by default* and if not, why not on processors that don't
doze? (powersave-nap is 0 here)

-- 
Matt Sealey <matt@genesi-usa.com>
Genesi, Manager, Developer Relations

Matt Sealey wrote:
> Hi guys,
> 
> Quick question, am I right (and looking at idle_6xx.S, I think I am) in 
> thinking that
> during the idle process, by default, an e600 core such as the 7448 or 
> MPC8610 will
> automatically transition to a NAP state, thus being as low power as 
> possible?